Non-Invasive Methods for Detecting Drug and Alcohol Impaired Drivers : - a Study of Alcohol and Drug Biomarkers and Optical Detection Techniques

(1)

Institutionen för Fysik och Mätteknik

Examensarbete

Non-Invasive Methods for Detecting Drug and

Alcohol Impaired Drivers

– a Study of Alcohol and Drug Biomarkers and Optical Detection Techniques

Sarah Broberg and Elin Diczfalusy

LITH-IFM-EX--09/2048--SE

Institutionen för fysik och mätteknik Linköpings universitet

(2)

(3)

Examensarbete LITH-IFM-EX--09/2048--SE

Non-Invasive Methods for Detecting Drug and

Alcohol Impaired Drivers

– a Study of Alcohol and Drug Biomarkers and Optical Detection Techniques

Sarah Broberg and Elin Diczfalusy

Handledare: Fredrik Winquist

ifm, Linköpings Universitet

Lena Kanstrup

Volvo Technology Corporation

Martti Soininen

Volvo Car Corporation

Examinator: Fredrik Winquist

ifm, Linköpings Universitet

(4)

(5)

Avdelning, Institution

Division, Department Division of Applied Physics

Department of Physics and Measurement Technology Linköpings universitet

SE-581 83 Linköping, Sweden

Datum Date 2009-01-30 Språk Language Svenska/Swedish Engelska/English Rapporttyp Report category Licentiatavhandling Examensarbete C-uppsats D-uppsats Övrig rapport

URL för elektronisk version

ISBN

—

ISRN

LITH-IFM-EX--09/2048--SE

Serietitel och serienummer

Title of series, numbering

ISSN

—

Titel

Title

Non-Invasive Methods for Detecting Drug and Alcohol Impaired Drivers

– a Study of Alcohol and Drug Biomarkers and Optical Detection Techniques

Författare

Author

Sarah Broberg and Elin Diczfalusy

Sammanfattning

Abstract

In recent years, the use of alcohol and psychoactive drugs in combination with driving has recieved increased attention. The lack of in-vehicle devices capable of detecting recent drug consumption and the difficulties associated with the breath-based alcolocks in use today makes it interesting to investigate methods that are able to non-invasivelly measure analytes directly in the blood.

The assignment of this project, commissioned by Volvo Technology Corpo-ration and Volvo Car CorpoCorpo-ration, is to map substances that constitute a possible threat to traffic safety, identify suitable detection markers as a proof of administration of these substances, and study possible non-invasive techniques to detect these markers. The objective is to present for Volvo if and how to continue evaluating and developing a non-invasive detection device.

The project has been carried out by performing an extensive literature study and a verification experiment. From the literature review, a number of substances affecting driving performance could be identified, and a metabolic study was performed for each drug to map suitable biomarkers. Furthermore, two potential techniques for non-invasive detection, near-infrared Raman spectroscopy and near-infrared spectroscopy, were found and evaluated. The experiment was conducted using near-infrared Raman spectroscopy, with the aim of investigating the sensitivity and linearity of the method for ethanol detection.

Based on the theoretical evaluation, both near-infrared Raman spectroscopy and near-infrared spectroscopy are expected to have potential for non-invasive detection of ethanol. The experiment further proved the theoretical conclusions made for near-infrared Raman spectroscopy. However, neither of the techniques is thought to have potential for drug detection.

Altogether, we believe that non-invasive ethanol detection is possible, but suggest further experiments in order to determine which technique to be preferred.

Nyckelord

(6)

(7)

Abstract

In recent years, the use of alcohol and psychoactive drugs in combination with driving has recieved increased attention. The lack of in-vehicle devices capable of detecting recent drug consumption and the difficulties associated with the breath-based alcolocks in use today makes it interesting to investigate methods that are able to non-invasivelly measure analytes directly in the blood.

The assignment of this project, commissioned by Volvo Technology Corporation and Volvo Car Corporation, is to map substances that constitute a possible threat to traffic safety, identify suitable detection markers as a proof of administration of these substances, and study possible non-invasive techniques to detect these markers. The objective is to present for Volvo if and how to continue evaluating and developing a non-invasive detection device.

The project has been carried out by performing an extensive literature study and a verification experiment. From the literature review, a number of substances affect-ing drivaffect-ing performance could be identified, and a metabolic study was performed for each drug to map suitable biomarkers. Furthermore, two potential techniques for non-invasive detection, near-infrared Raman spectroscopy and near-infrared spectroscopy, were found and evaluated. The experiment was conducted using near-infrared Raman spectroscopy, with the aim of investigating the sensitivity and linearity of the method for ethanol detection.

Based on the theoretical evaluation, both near-infrared Raman spectroscopy and near-infrared spectroscopy are expected to have potential for non-invasive de-tection of ethanol. The experiment further proved the theoretical conclusions made for near-infrared Raman spectroscopy. However, neither of the techniques is thought to have potential for drug detection.

Altogether, we believe that non-invasive ethanol detection is possible, but suggest further experiments in order to determine which technique to be preferred.

(8)

Sammanfattning

På senare år har användningen av alkohol och narkotikaklassade preparat i kom-bination med körning fått ökad uppmärksamhet. Bristen på fordonsintegrerad utrustning som kan detektera nyligen intagna droger och svårigheterna som förknip-pas med de utandningsluftsbaserade alkolås som används i dag gör det intressant att finna metoder som transkutant kan detektera analyter direkt i blodet. Syftet med detta projekt, som utförs på uppdrag av Volvo Technology Corpora-tion och Volvo Car CorporaCorpora-tion, är att kartlägga substanser som utgör ett möjligt hot mot trafiksäkerheten, identifiera lämpliga biologiska markörer som utgör bevis för intag av dessa substanser, och att undersöka potentiella metoder för detektion av dessa markörer genom huden. Målet är att presentera för Volvo huruvida man bör fortsätta att utvärdera och utveckla en transkutan mätmetod, och hur man i sådana fall skall gå tillväga.

Projektet har genomförts genom att utföra en omfattande litteraturstudie och ett kontrollexperiment. Utifrån litteraturstudien kunde ett antal substanser som påverkar körförmågan identifieras, och en metabolisk studie utfördes för respek-tive substans för att kartlägga lämpliga biomarkörer. Vidare identifierades och utvärderades två potentiella detektionsmetoder för mätning genom hud: near-infrared Ramanspektroskopi och near-near-infrared spektroskopi. Med syftet att un-dersöka teknikens känslighet och linjäritet vid etanoldetektion, utfördes ett exper-iment med near-infrared Ramanspektroskopi.

Baserat på den teoretiska utvärderingen, bör både near-infrared Ramanspektroskopi och near-infrared spektroskopi ha potential för etanoldetektion genom hud. Det utförda experimentet bekräftar de teoretiska slutsatserna vad gäller near-infrared Ramanspektroskopi. Dock tros ingen av de studerade teknikerna ha potential för detektion av narkotika.

Sammantaget tror vi att icke-invasiv etanoldetektion vara möjlig, men föreslår ytterligare experiment för att avgöra vilken teknik som är att föredra.

(9)

Acknowledgments

This master thesis has been performed as a cooperation project between Volvo Technology Corporation, Volvo Car Corporation and the University of Linköping, from August 2008 to January 2009.

Many have helped us to enable the realization of this project. Initially, we would like to thank our supervisors at Volvo, Lena Kanstrup at Volvo Technology and Martti Soininen at Volvo Cars, for all the support and help they have given us. We would also like to thank our supervisor and examiner, Fredrik Winquist, professor at the Division of Applied Physics at Linköping Institute of Technology (LiTH), for feedback and support during our work.

Furthermore, we would like to thank the following persons, who have contributed with help to this project in different ways:

Wayne Jones, Adjunct Professor, University of Health Sciences, Linköping Annika Enejder, Associate Professor, Chalmers University of Technology Fredrik Svedberg, Doctor, Chalmers University of Technology

Stig Boman, Volvo 3P

Göteborg Science Centre for Molecular Skin Research

Birgitta Odén, Research Laboratory Assistant, Sahlgrenska University Hospital Finally we would thank all of the employees at Volvo Technology and Volvo Cars who have helped us and made our work a great time.

Sarah Broberg and Elin Diczfalusy Göteborg, January 2009

(10)

(11)

Acronyms and Abbreviations

ATP Adenosine Triphosphate

BAC Blood Alcohol Concentration

BZD Benzodiazepine

CNS Central Nervous System

DUI Driving Under the Influence

DUID Driving Under the Influence of Drugs

GI tract Gastrointestinal tract

IR Infrared

MEOS Microsomal Ethanol Oxidizing System

NA Numerical Aperture

NAD+ Nicotinamide Adenine Dinucleotide

NADH Nicotinamide Adenine Dinucleotide, reduced form

NIR Near-Infrared

(12)

(13)

Glossary

Acetylation reaction A reaction where an acetyl group is introduced into an organic compound.

Acetyl group A chemical functional group with the chemical

for-mula -COCH3.

Adenosine triphosphate A small molecule that serves as the main carrier of energy in the cellular metabolism. It is formed by phosphorylation of adenosine diphosphate during respiration.

Alkylation reaction Transfer of an alkyl group from one molecule to an-other.

Alkyl group A chemical compound consisting of a chain of

hydrogen-bound carbon atoms, with the general for-mula CnH2n+1.

Amide A functional group containing a carbonyl group

linked to a nitrogen atom.

Antitussive A drug used to suppress coughing.

Anxiolytic A drug used for treatment of anxiety.

Aromatic compound A cyclic organic compound characterized by its sta-bility resulting from delocalized electrons, i. e. the ring structure contains multiple conjugated double bonds.

Artery A blood vessel that carries oxygenated blood from

the heart and lungs to the rest of the body.

Back-scattered light The reflection of photons to the same direction they came from.

Biomarker Biochemical substances in the body that can indicate

the presence or progress of a condition, or any genetic predisposition toward it.

Blood-brain barrier A permeable barrier that controls the passage of large molecules, such as drugs and other substances, from the blood to the brain tissue.

Capillary The smallest of the body´s blood vessels, that

con-nect arteries and veins. Interchange of oxygen, wa-ter, carbon dioxide, nutrients and waste material between the blood and the surrounding tissue take place across the capillary walls.

(14)

xii

Binge use Excessive consumption of substances such as alcohol

and drugs.

Circulatory system A system that consists mainly of the heart, the blood and the blood vessels, which functions as a trans-portation system for nutrients, gases and waste ma-terial in the body.

Conjugated compound Formed by the union of two compounds.

Cytochrome P450 A superfamily of enzymes that are involved in drug

system metabolism. These enzymes are primarily found in

the liver, where they transform many drugs into less toxic forms to facilitate excretion from the body.

Dipole moment A measure of the polarity of a bond or molecule, i. e. the product of either charge in an electric dipole with a distance separating them.

Electric dipole A separation of negative and positive charge.

Elimination half-life The time it takes for a drug to lose half of its activity.

Endogenous Produced by naturally occurring processes in the

body.

Fermi resonance When two vibrational states in a molecule possess the same energy and therefore interact with each other, resulting in a splitting of spectral lines.

First passage Metabolism that can occur in the stomach and the

metabolism liver after oral administration, taking place before the substance reaches the circulatory system.

Fluorescence An optical phenomena where molecular absorption

of a photon results in emission of a photon with less energy.

Gastrointestinal tract The entire length of the digestive system, running from the mouth to the anus. The major functions of this system is ingestion of food product, digestion to extract energy and nutrients, absorption, and defe-cation of waste products.

Glucuronidation A reaction where glucuronic acid is linked to a

reaction compound.

Hydroxylation reaction A chemical reaction that links one or more hydroxyl groups to a compound resulting in an oxidation.

In vivo Taking place inside an organism.

Intermediate Compounds formed from a reactant of a chemical re-action, which is further transformed to give the prod-uct of the reaction. Most intermediates are short-lived and unstable.

Kinetics The study of rates of chemical reactions and the

fac-tors they depend on.

Lipophilic The ability of a chemical compound to dissolve in

fats.

(15)

xiii

Methylation reaction A chemical reaction that attach or substitute a methyl group to a molecule.

Microcentrifuge tube Small, cylindrical container made of plastic, with rounded bottom. Also known as Eppendorf tube.

Microsomal Ethanol An enzyme system, part of the P450-system, that

Oxidizing System oxidizes ethanol.

Nicotinamide Adenine The coenzyme NAD+ binds to hydrogen atoms

Dinucleotide during ethanol metabolism, resulting in its reduced form NADH. Together, these molecules move hydro-gen atoms and thereby electrons back and forth be-tween chemical reactions within the cell.

Normal vibrational A pattern of movements where all parts of a system,

mode such as a molecule, move with the same frequency.

Non-invasive Through unbroken skin.

Numerical aperture A number that indicates the angular resolution of a microscope objective, characterizing the angles over which a system can emit or accept light.

Oxidation reaction A reaction resulting in a loss of electrons. This re-action type often involves adding an oxygen atom or removal of a hydrogen atom, or both.

Oxidative metabolism A chemical process in which energy is obtained from a chemical bond by adding of oxygen or removal of hydrogen.

Petri dish A small, shallow circular dish of thin glass or plastic, often used to culture bacteria or other microorgan-isms.

Phase I-metabolism Part of the metabolism where drugs and other foreign chemical compounds are oxidized, reduced or hy-drolyzed making the substances less toxic and more water-soluble.

Phase II-metabolism Part of the metabolism where specific enzymes trans-form drugs and other foreign chemical compounds into more water-soluble substances, facilitating ex-cretion of the substance through the urine.

Plasma The liquid in the blood in which the red blood cells

and erythrocytes are suspended.

Polarizability A measurement of the tendency of an electron cloud to be distorted after the atom has been exposed to an external electric field.

Polymorphism The existence of a gene in more than one form in a population.

Potency The relationship between the effect of a drug and the

dose required to produce the effect.

Psychoactive substance A substance that acts on the central nervous system, and thereby affects brain functions.

Sedation The use of a drug that reduces excitement and

(16)

xiv

Spectroscopy The study of the interaction of radiation with matter, as a function of wavelength.

Tranquilizer A drug used for reduction of stress or tension without reducing mental clarity.

Transcutaneous Through unbroken skin.

Vein A blood vessel that carry oxygen-poor blood back

from tissue and organs to the heart.

Whole blood Blood with all its components (plasma, proteins,

platelets, red blood cells and white blood cells) in-tact.

Withdrawal symptoms Characteristic symptoms that appear when drug use is discontinued after regular use.

(17)

Introduction

The fact that alcohol, and more specifically ethanol, affects driving skills is long-time known. Alcohol was recognized as a threat to traffic safety already in the 1920s [6].

A major breakthrough came as early as in the end of the 19th century, when researchers found a quantitative way to detect alcohol in body fluids. The ability to perform quantitative measurements, in combination with the increased risk of traffic accidents, following alcohol administration have led to legislation regarding drunk driving [6].

In recent years the use of psychoactive drugs in combination with driving has recieved much attention [67]. Most countries around the world have introduced legislations regarding driving under the influence of drugs (DUID). If any measur-able amounts of illicit drugs can be found in the blood of the driver legal action will be taken [67, 66, 68].

In this project, which is commissioned by Volvo Car Corporation and Volvo Tech-nology Corporation, new methods for alcohol and drug detection will be investi-gated.

1.1 Volvo Car Corporation

Volvo Car Corporation, VCC, is owned by Ford Motor Company since 1999. The company was founded in 1927, and it is a global car manufacturer with markets and sales networks covering about 100 countries. The name ’Volvo’ is owned jointly by Volvo Cars and Volvo Group, and is considered one of the strongest brands within the industry.

(22)

2 Introduction

1.2 Volvo Technology Corporation

Volvo Technology Corporation, VTEC, is a business unit within Volvo Group. It is an innovative company which develop new technologies and concepts for products and processes within the transportation and automotive industry. Volvo Technol-ogy works not only with internal customers, but also with external customers such as Volvo Cars.

1.3 Alcohol Detection at Volvo

Already in 1927, when Volvo was founded, the founders, Assar Gabrielsson and Gustaf Larsson, declared:

Cars are driven by people. The basic principle behind everything we make at Volvo is - and must always remain - safety [32].

Ever since then, Volvo has put much effort into preventing and limiting accidents and introduce and develop new safety systems [151, 32]. Part of this work has been the development of alcolocks, an area in which Volvo are in the forefront. Since the early 21st century, both Volvo Cars and Volvo Group have offered alcolocks as an option in their vehicles, and since 2005 they offer fully integrated alcolocks [1, 32].

Both Volvo Cars and Volvo Group are members of the KAIA project group, a project aiming to demonstrate and validate the alcolock technology where exhaled air is studied by IR spectroscopy. Through this project, the companies together with a number of cooperation partners work on the further development of alcolock solutions to improve factors such as application handiness and reliability and at the same time making the device harder to manipulate [150].

1.4 Techniques Available Today

Alcolocks in use today are all based on analysis of breath, taking advantage of the fact that a fraction of the consumed ethanol is emitted through the lungs. Most devices contain fuel-cell ethanol sensors, a technique that uses the fact that free electrons are generated when ethanol is oxidized. These electrons give rise to a current, whose strength is proportional to the amount of ethanol molecules that reach the fuel cell [6]. Other techniques, such as semiconductor-based breath ethanol analyzers, are under development. Most alcolocks have additional sensors for breath temperature, pressure and/or air flow, to prevent manipulation of the device and thereby minimize the risk of false negative results [116].

Within forensic science, blood tests and breath analyzers are used to detect ethanol consumption. Forensic breath analyzers are mainly based on infrared absorption, using three different wavelengths to ensure the accuracy of the measurements.

(23)

1.5 Background of this project 3

Blood samples are mainly analyzed using three different methods: chemical oxida-tion (Widmarks test), enzymatic oxidaoxida-tion (ADH method) or gas chromatography [6].

No in-vehicle drug detection devices are available today. Within forensic sci-ence, immunochemical screening methods are used to analyze blood and urine, and following a positive screening these results are verified by using more sensi-tive and reliable methods such as gas chromatography, liquid chromatography and spectrophotometry [6].

1.5 Background of this project

Ethanol and drugs affect the cells in the body, resulting in transformation and chemical breakdown of the substance [13, 12]. The idea of this project is to take advantage of this fact, and evaluate the possibility to detect these cellular and chemical changes transcutaneously.

Despite the extensive development, the breath analyzing technique used in al-colocks today still has the disadvantage that the relation between blood alcohol and breath alcohol concentration differs between individuals [6]. In addition, most drugs are non-volatile and can therefore not be detected using a breath analyzer. These are just some of the factors that make it interesting to investigate and eval-uate possible methods that are able to non-invasivelly measure suitable analytes directly in the blood.

The starting point of this project was when Volvo got in contact with a company that had developed a sensor capable of detecting body analytes non-invasivelly. The reasons for not further developing this cooperation are described in Chapter 6.

(24)

(25)

Chapter 2

Purpose and Research

Questions

In this chapter the assignment, purpose, objective, research questions and limita-tions will be presented.

2.1 Assignment

The assignment of this project, which is commissioned by Volvo Car Corporation and Volvo Technology Corporation, hereinafter jointly referred to as Volvo, is to investigate the potential of a non-invasive alcohol and drug detection technique. More specifically, the assignment includes:

• A mapping of substances, alcohol and drugs, that affect driving skills. • Identification of biological markers as a proof of administration of these

substances.

• A study of possible detection techniques for identification of these mark-ers, the reliability of these techniques and potential disturbing factors which might affect measurements.

The assignment implies evaluating an already existing method, based on fluores-cence spectroscopy using UV-light, and examine whether Volvo should continue developing this technique to fit their needs. Elsewise, investigate other possi-ble non-invasive techniques and make conclusions on which method is the most promising. The chosen method will then be further evaluated.

A basic experiment using a non-invasive technique will be conducted in order to practically confirm the result of the theoretical conclusions and receive the data needed for further analysis.

(26)

6 Purpose and Research Questions

2.2 Purpose and Objective

The purpose of this project is to investigate the potential of a non-invasive method for alcohol and drug measurements. The objective is to propose suitable biomark-ers for detection of alcohol and drugs, and determine, based on their sensitivity and physical principles, whether there is a non-invasive technique capable of de-tecting these biomarkers. The objective is also to provide Volvo with extensive information regarding the metabolism of alcohol and drugs, and present if and how they should continue evaluating and developing a non-invasive alcohol and drug detection device.

2.3 Research Questions

The focus of this report will be on the following research questions:

• Which substances in use today can be considered a threat to traffic safety? -Which drugs are commonly used by car drivers?

-Which drugs are commonly used by truck drivers?

-Alcohol and drugs: how many accidents are caused by these substances? -Which effects produced by these drugs can adversely affect driving ability? • Which potential biomarkers can be used to detect administration of the

following substances? -Alcohol

-Drugs

• Which non-invasive technique has the potential to detect the chosen biomark-ers?

2.4 Limitations

The limitations of this report will be as follows:

• This study considers only substances most common and dangerous in com-bination with driving.

• In this report, non-invasive techniques refer strictly to optical methods. • In this project, only statistics regarding cars and trucks will be considered. • In this report, the statistics will only include the top ten countries in regard

to the amount of sold vehicles by both Volvo Cars and Volvo Trucks. These are listed in Table 2.1.

(27)

2.5 Method 7

Table 2.1. Top ten selling countries for Volvo Cars (3rd quarter of 2008) [141] and

Volvo Trucks (first half of 2008) [20], downward order.

Volvo Cars Volvo Trucks

United States of America United States of America

Sweden Brazil

The Netherlands Germany

Belgium United Kingdom

France France

United Kingdom Russian Federation

Spain Spain

Italy Italy

Germany The Netherlands

China Belgium

• The assignment is not to implement and/or develop a new non-invasive al-cohol and drug detection device, but to investigate the potential of these methods.

• The experimental part will only take ethanol into consideration.

2.5 Method

The main activities of the project are summarized in Figure 2.1.

Figure 2.1. Overview of the main activities in this project.

In order to determine whether there is a technique capable of detecting alcohol and drugs non-invasivelly, the conditions have to be investigated. This will be done by performing a comprehensive literature review, covering drug statistics, drug metabolism and optical detection methods. The literature data will then be compiled and evaluated.

A cooperation with the Department of Molecular Imaging and Biotechnology at Chalmers University of Technology will be established, to be able to set up and per-form an experiment using their expertise and equipment. The experiment should

(28)

8 Purpose and Research Questions

not be considered one of the main activities of this project, but will be performed to get an idea of the possibilities with a non-invasive technique.

The comparison of biomarkers will be performed by setting up a number of crite-ria, from which each biomarker will be evaluated.

As a starting point regarding detection techniques, one specific technique will be studied. If this technique is considered unsuitable for non-invasive detection of alcohol and drugs, other techniques will be identified and evaluated based on a number of requirements.

2.6 Project Outline

In the following chapters we will investigate the possibility of detecting alcohol and drug biomarkers non-invasivelly and present the most promising techniques for this purpose.

Chapter 3 introduces the substances that will be included in this project, and

presents statistical evidence to confirm the choice.

Chapter 4 describes the effects of the chosen substances, focusing on the

ef-fects that can affect driving skills.

Chapter 5 introduces the concepts metabolism and biomarkers. In addition,

the properties of the chosen drugs and their metabolites are studied in detail.

Chapter 6 presents the technique that inspired Volvo to initiate this project,

and the factors that tell against continue developing this technique.

Chapter 7 presents the technical requirements on the detection techniques. Two

potential techniques for non-invasive detection are introduced, followed by a de-tailed description.

Chapter 8 describes the ethanol detection experiment performed.

Chapter 9 presents the results from the literature study and the ethanol

de-tection experiment.

Chapter 10 illuminates and discusses important results and choices.

Chapter 11 provides the answers to the research questions in Section 2.3. Also,

(29)

Chapter 3

Substance Selection

In this chapter, the substances chosen to be included in this project are presented. Drugs are divided into classes according to Appendix A. In this project, five drug classes were selected based on a risk assessment performed by the project CER-TIFIED [16]. One or two substances from each selected drug class were chosen for review, including the alcohol ethanol and six illicit and/or abused drugs. The chosen drug classes and substances are summarized in Table 3.1.

Table 3.1. Estimated risk of the chosen drug classes in combination with driving. Drivers are assumed to include both car drivers and truck drivers.

Drug class Substance Estimated risk* [16]

Alcohols Ethanol High

Cannabinoids Marĳuana Moderate

CNS stimulants Methamphetamine/ Moderate

Amphetamine

Opioids Heroin/ Low-moderate**

Morphine

Benzodiazepines Diazepam High

*Risk estimation based on impairment effects, prevalence in population and association with traffic accidents.

**The drug class was chosen based on its strong sedative effects, although it´s classified as a low-risk drug due to its low prevalence in the general driving population.

(30)

10 Substance Selection

Each individual substance was selected after studying statistical material regard-ing prevalence and relative risks of drugs in combination with drivregard-ing. Substances that were believed to have a high prevalence among drivers suspected of being under the influence of drugs (DUID) and among injured drivers were selected. Figure 3.2 (page 14) illustrates the prevalence of the chosen drug classes among injured drivers, while the prevalence among drivers suspected of being under the influence of drugs can be seen in Figure 3.3 (page 15). For exact numbers and ref-erences, see Appendix B. The numbers are based on data obtained from different studies, conducted in different parts of the world, focusing on the top ten selling countries for Volvo Cars and Volvo Trucks (Table 2.1). As far as possible, recent statistical material has been used, but there are still differences regarding sam-ple sizes and drug identification methods. Therefore these data should be viewed with extreme caution. The purpose of the summarization is not to provide exact numbers, but rather to indicate the prevalence and potential harmfulness of the chosen drug classes.

3.1 Ethanol

Ethanol is long time known and accepted as a threat to road safety and has been identified as the most important contributing factor to road traffic accidents [148]. Also, it is by far the most common substance found among drivers involved in traffic law offenses [54]. The prevalence of ethanol among fatally injured drivers and drivers suspected of being under the influence of ethanol is summarized in Table B.1 and Table B.2.

Although the data regarding ethanol among fatally injured truck drivers is lim-ited, the numbers found are included in the summarization. In the general truck driving population, the prevalence is around 5% [90].

As early as in the 1960´s, the increased risk of being responsible for a crash during drunk driving was highlighted. Based on a major study, the relative crash risk related to the blood alcohol concentration was estimated, see Figure 3.1. The significant increase in crash risk has been confirmed by several case-control studies [49].

(31)

3.2 Marĳuana 11

Figure 3.1. Relative crash risks for different BAC values [49]. Notice that a logarithmic

scale is used.

3.2 Marĳuana

Marĳuana is one of the most frequently used drugs among drivers worldwide [50, 71]. The presence of cannabinoids in car drivers involved in severe accidents has been reported to vary from 2.2–19.1 %, but typically lies around 10 % [11, 18]. There is limited data available regarding the prevalence of illicit drugs among truck drivers in general, but in two studies performed the prevalence ranges from 0.3–8.5 % [90].

As can be seen in Table B.1 and Table B.2, cannabinoids are common among DUID suspects as well as fatally injured drivers.

Although the exact role of marĳuana as an accident factor is unclear, several recent studies have identified marĳuana as a possible threat to traffic safety. A responsibility study performed in 2004 has shown that drivers under the influence of marĳuana are more likely to be responsible for accidents. In this study, drivers who had consumed marĳuana were 2.7–6.6 times more likely to be responsible for an accident, depending on the consumed dose, compared to non-consumers [44]. A case-control study performed in 2000-2001 showed evidence that drivers under the influence of marĳuana are 2.5 times more often involved in accidents compared to non-users [111, 91].

Marĳuana is often used together with alcohol and other drugs, a fact that should be considered when evaluating marĳuana as a potential accident factor [152]. Case-control studies have proved that driving under the influence of marĳuana in

(32)

com-12 Substance Selection

bination with alcohol increases the accident risk more than either substance alone [17, 50].

3.3 Methamphetamine/Amphetamine

Amphetamine and methamphetamine, referred to as amphetamines, are two of the most common substances belonging to the drug class known as central ner-vous system (CNS) stimulants. These substances are frequently listed as drugs commonly used by drivers [16], especially in the Scandinavian countries.

The prevalence of CNS stimulants among fatally injured drivers worldwide varies from 3.7–15.0 %, while 5.8–62.9 % is true for drivers suspected of being under the influence of drugs, as shown in Table B.1 and Table B.2 [77, 54].

With its stimulating effects, amphetamines are common among long-distance truck drivers [38], with a prevalence of 4.8 % found in a study of general truck drivers [137].

3.4 Heroin/Morphine

Research and studies done around the world have shown, not only, what illicit drugs are most commonly found in DUID but also the most frequently found drugs in fatally injured drivers. One of the drug classes highlighted as a result of this research is opioids, including the drugs heroin and morphine [69, 38]. Study-ing the population of drivers suspected of drivStudy-ing under the influence of drugs, the presence of opioid impaired drivers ranges between 1.0–23.6%. Opioid impaired drivers are, as seen in Table B.1 and Table B.2, also involved in traffic accidents to a great extent [40].

The data regarding the prevalence of opioids among truck drivers is very lim-ited. In 2003-2004 one thousand truck drivers were studied in France to see what drugs where commonly used by these workers. The tests showed that 41 out of 1000 (4.1%) drivers tested positive for opioids. It is worth noting, though, that the majority of the substances found are used as main ingredients in antitussives and do not prove illegal drug use [90].

Although the prevalence varies a lot between different studies, opioids affect the driver with strong sedation which in fact makes them high risk drugs when study-ing the danger for road traffic [16]. A case-control study has shown that drivstudy-ing under the influence of heroin and/or morphine is associated with significantly in-creased accident risk [106]. A study done in 2005 showed an inin-creased risk of being involved in a car accident after using natural opium alkaloids such as morphine. Although there are no major difference in the risk of being involved in a car ac-cident between the sexes while using opium alkaloids it showed an increased risk for users in the age of 18–54 years compared to older users [47].

(33)

3.5 Diazepam 13

3.5 Diazepam

Diazepam, also known as Valium, belongs to the drug class benzodiazepines. This substance is not only one of the most common licit drug found in in the general population but also in the population suspected of DUID [40, 69]. Worldwide studies have shown that the frequency of finding benzodiazepines in fatally in-jured driver lies within the range of 3.4–14.0% (Table B.1 and Table B.2), with diazepam being one of the most common BZD´s found [50].

Less is known about truck drivers use of benzodiazepines. About 0.4% of the truck drivers use the drug regarding to a French study done in 2002–2003. This number is lower than expected due to the low sensitivity of the test used [90].

Not only are Benzodiazepines a danger when used illicitly. Many studies show that even therapeutic doses of the drug constitute a risk for traffic safety. This is especially true for the first days of use [67]. Benzodiazepines are most commonly detected in the therapeutic range and together with illicit drugs and/or ethanol [69, 43, 96].

Countless studies have been done regarding the driving and psychomotor per-formance effects of benzodiazepines. As one of the most extensively evaluated benzodiazepines, diazepam has been shown to significantly impair driving skills and increase the accident risk [43, 47, 155]. The injury risk after using benzodi-azepines can rise up to 5 times [47, 159], and more specifically threefold in the case of diazepam [39]. Patients recieving benzodiazepine anxiolytics over an 8–week pe-riod have been shown to have a 2.5 times increased risk of fatal injury due to traffic accidents, showing that long-term use of the drug also affects performance [155]. The risk for users are higher for people in the age of 18-54 years, but no differences has been seen between the sexes [47]. Taking those things into account, benzodi-azepines has been ranked a high risk drug because of its danger for road traffic [16].

(34)

14 Substance Selection

Figure 3.2. Prevalence [%] of the studied drug classes among injured drivers, country-specific data. For exact numbers and references, see Appendix B. Drivers are

assumed to include both car drivers and truck drivers. USA = United States, S =

Sweden, NL = The Netherlands, B = Belgium, F = France, GB = United Kingdom, E = Spain, I = Italy, D = Germany, RC = China, RUS = Russian Federation, BR = Brazil.

(35)

3.5 Diazepam 15

Figure 3.3. Prevalence [%] of the studied drug classes among drivers suspected of being

under the influence of drugs, country-specific data. For exact numbers and references, see Appendix B. Drivers are assumed to include both car drivers and truck drivers. USA = United States, S = Sweden, NL = The Netherlands, B = Belgium, F = France, GB = United Kingdom, E = Spain, I = Italy, D = Germany, RC = China, RUS = Russian Federation, BR = Brazil.

(36)

(37)

Chapter 4

Effects of the Chosen

Substances

All of the chosen substances give rise to a number of psychological effects in the human body. In this chapter, the general behavioral effects as well as the effects on driving performance are reviewed for each substance.

4.1 Ethanol

Ethanol belongs to the chemical compounds known as alcohols, most of which are highly toxic to the human body [6]. Although less toxic than other alcoholic compounds, ethanol affects human behavior and performance strongly [49]. The behavioral changes are summarized in Table 4.1.

The clinical effects of ethanol on body functions are well mapped [93]. Ethanol affects the body in a dose-dependent manner which has been extensively evalu-ated, and the relationship between ethanol consumption, driving impairment and increase in traffic accident risk is well documented [100]. Appendix C describes the performance and behavioral effects associated with different blood alcohol concen-tration (BAC) levels. Based on this relationship, most countries have established legal limits for blood alcohol concentration during driving [111], see Appendix D. This relationship is not precisely clear, however; factors such as ethanol tolerance and previous driving experience contribute to the total driving impairment, and the effect of low doses of ethanol on driving performance is still not fully estab-lished [122].

(38)

18 Effects of the Chosen Substances

Table 4.1. Effects of ethanol consumption.

General Psychological Effects Effects on Driving Performance

Low doses (<0.05 %): relaxation, mild euphoria, altered judgement, lowered alertness [49]. Moderate doses (0.05–0.10 %): impulsive be-havior, impaired motor function, less caution, likely to take risks and ac-tions not taken when sober [49]. High doses (0.1–0.3 %): large increases in reaction time, balance impairment, major memory impairment, possible blackout and consciousness [49].

Increased brake reaction time, in-creased collision frequency, dein-creased

speed control, lowered steering

responsiveness and lane control, changes in risk-taking behavior, decision making and planning [83].

4.2 Marĳuana

Marĳuana belongs to the drug class cannabinoids [117]. This drug class involves all drug substances containing any of the substances chemically known as cannabi-noids. Cannabinoids have a broad and unique spectrum of behavioral effects, which prevent them to be classified as stimulants, sedatives, tranquilizers or hal-lucinogens [33, 11]. The effects of marĳuana use are summarized in Table 4.2.

Table 4.2. Effects of marĳuana use.

Low doses: euphoria, relaxation, sense of well-being, altered time and space perception, lack of concentra-tion, drowsiness and mood changes such as paranoia [33]. High doses: image distortion, dulling of attention, panic attacks, psychosis [71, 33].

Impaired car handling, impaired time and distance estimation, increased re-action time [33, 11], increased deci-sion times to evaluate situations and determine appropriate responses [33].

Experimental studies have shown that marĳuana consumption leads to impaired performance in driving simulators, in a dose-related manner [11]. A Norwegian study has proposed a linear relationship between the blood concentration of THC, the main active component in marĳuana, and the driving performance, where the first impairing effects can be seen at blood plasma concentrations as low as 0.003 µmol/L and where concentrations of 0.02 µmol/L corresponds to a blood ethanol

(39)

4.3 Methamphetamine/Amphetamine 19

level of 1 per mille [85]. However, most studies indicate that there is no clear relationship between the blood plasma concentration of THC and the impairing effects [71, 33].

4.3 Methamphetamine/Amphetamine

Methamphetamine and amphetamine belong to the drug class CNS stimulants, a drug class generally characterized by behavioral effects such as increased energy and mental alertness [117]. The more specific effects characterizing amphetamine and methamphetamine use are summarized in Table 4.3.

Table 4.3. Effects of amphetamine and methamphetamine use.

Early effects: euphoria, exhilaration, rapid flight of ideas, motor restless-ness, hallucinations, increased alert-ness, feelings of increased physical strength, poor impulse control [109, 33]. Late effects: dysphoria, restless-ness, nervousrestless-ness, paranoia, aggres-sion, lack of coordination, psychosis and drug craving [33].

Inattentive driving, high speed, im-patience, high risk driving [33], poor compliance with road rules, increased risk of falling asleep at the wheel [160].

Several trials in driving simulators have shown that mild to moderate doses of amphetamines do not significantly impair driving skills; in fact, the use of low doses of amphetamines can sometimes benefit driving performance by improving attention and relieve symptoms of sleepiness [25]. On the other hand, high doses of amphetamines as well as withdrawal symptoms are associated with impaired driving performance [160].

4.4 Heroin/Morphine

Heroin and morphine belongs to the group of drugs known as analgesics, sub-stances that provide relief from pain. Analgesics are further divided into classes depending on how strong the effect of the substance is, placing heroin and mor-phine in the class of narcotic analgesics, also referred to as opioids [33, 11]. Heroin is a semisynthetic derivate synthesized from the natural occurring substance mor-phine by acetylation [33, 84]. This change in the chemical structure makes heroin 2-3 times more potent than morphine [84], resulting in a rapid and strong feeling of euphoria [33].

(40)

20 Effects of the Chosen Substances

Not only are opioids used as painkillers but they are also used clinically for their antitussive properties [84, 33].

The general effects after heroin or morphine administration depends on factors such as the dose taken and the route of administration. Previous exposure to the drug will also influence the effects [33, 11]. The effects of heroin/morphine use are summarized in Table 4.4.

Table 4.4. Effects of heroin/morphine use.

Euphoria, sense of well-being, relax-ation, drowsiness, sedrelax-ation, delirium [33].

Slow driving, poor vehicle control, poor coordination, slow response to stimuli, delayed reactions, diffi-culty in following instructions, falling asleep at the wheel [33].

4.5 Diazepam

As one of the most commonly prescribed drug classes in the world, benzodiazepines have become the major class of central nervous system depressant drugs [79]. Diazepam belongs to the group of long-acting benzodiazepine tranquilizers and is used as a licit drug [80, 47]. It is commonly prescribed as a muscle relaxant, sedative and for the management of anxiety and epilepsy. Even when used as a prescribed drug in recommended doses, diazepam can have significant effects on psychomotor function [79]. Table 4.5 summarizes the effects caused by the use of diazepam.

Table 4.5. Effects of diazepam use.

Sleepiness, drowsiness, confusion, se-vere sedation, disorientation [33], am-nesia [43].

Increased reaction time, impaired cognition, impaired capacity to per-form simultaneous operations [43], decreased attention, decreased eye-hand coordination [33].

(41)

Chapter 5

Drug Metabolism and

Potential Biomarkers

In this chapter, the properties of each drug will be studied in more detail, to find suitable biomarkers. To start with, metabolism as a concept will be described, followed by a specification of biomarker requirements. Finally, the properties of the biomarkers for each drug are presented.

5.1 Cell Metabolism

Definition 5.1 (Metabolism) All of the chemical reactions within an organism

that transform molecules and consume and generate energy [2].

Metabolism is all about how to obtain energy from food products or correspon-dent complex compounds, and how this energy is used by the cell to maintain life. Two principles regulate the metabolism: the need for energy and the energy ac-cess. Several chemical reactions are required to follow these two principles. These reactions can all be controlled by the cell through specialized proteins known as enzymes. The role of each enzyme is to accelerate, or catalyze, a specific reaction involved in cell metabolism. By regulating the amount of the specific enzymes, each reaction can be controlled by the cell [5, 48].

According to the metabolism-regulating principles, the chemical reactions that oc-cur in a cell can follow two different pathways known as anabolism and catabolism. In the catabolic pathways, molecules are broken down into smaller molecules re-sulting in energy generation. The opposite is true for the anabolic pathways, where energy is consumed in order to synthesize molecules needed by the cell. Each reac-tion catalyzed by an enzyme triggers a new reacreac-tion, resulting in that the product of each reaction forms the substrate for the next. The individual reaction pathways are linked to one another, forming a network of reactions (Figure 5.1) enabling the cell to grow and maintain life [5].

(42)

22 Drug Metabolism and Potential Biomarkers

Figure 5.1. A selection of the metabolic pathways and their interconnections in a representative cell [5].

While ethanol can be metabolized and used for energy generation by the body, drugs are regarded as foreign substances and can not be used for this purpose. Instead, drug metabolism is the process by which the structure of the drug is modified to facilitate removal from the body. Even though the liver is the major metabolic organ, some other sites such as the lungs, kidneys, gastrointestinal (GI) tract and the blood are involved. Drug metabolism is divided into two phases, phase I and phase II metabolism [142]. A metabolic transformation of a drug can result in either an active or an inactive metabolite, see Definition 5.2.

Definition 5.2 (Active metabolite) When a metabolite of a drug produces a

therapeutic effect, it is considered an active metabolite [36, 2].

Psychoactive substances and their active metabolites produce their behavioral ef-fects mainly by acting on brain receptors; a process not coupled to the metabolism of the drug [125].

There are several possible administration routes for drugs, all affecting the distri-bution route and time profile. The most common routes, studied in this chapter, are listed below.

(43)

5.2 Biomarker Requirements 23

• Oral: The drug is absorbed through the gastrointestinal tract. This results in a first-passage metabolism, meaning that the drug is partly metabolized in the GI tract and the liver before it reaches the general circulation [142]. • Smoking/Inhalation: The drug is absorbed through the lungs, which

re-sults in a rapid absorption because of the high perfusion degree of this organ. First-passage metabolism is avoided in this administration route [130]. • Intravenous: The drug is injected directly into the bloodstream, making

this route the most efficient one. First-passage metabolism is avoided in this administration route [142].

• Intranasal: The drug is absorbed through the nose, which results in a rapid absorption because of the high perfusion degree of this organ. First-passage metabolism is avoided in this administration route [130].

• Intramuscular: Injection directly into muscles, resulting in variable ab-sorption [142].

5.2 Biomarker Requirements

Definition 5.3 (Biomarker) A phenomenon or quantity that, when detected

or excessing a certain value, constitutes an indicator that a certain biological condition is forthcoming, or can be expected, in an organism or biological system [3].

Definition 5.4 (Biomarker) Biochemical substances in the body that can

indi-cate the presence or progress of a condition, or any genetic predisposition towards it, are called biomarkers [86].

Definition 5.3 constitutes the formal definition of a biomarker. In this project, the word biomarker will refer to a biochemical substance in the body that can indicate the presence or progress of a condition, i.e. Definition 5.4. More specifically, a biomarker can be either the substance itself or one of its metabolites. Biomarkers can be used as a screening tool to discover whether a person is under the influence of alcohol or drugs.

An ideal biomarker needs to have the following features:

• Specificity, the ability to identify persons that have not consumed the specific drug with a high accuracy [86].

• Detection window, the ability of the biomarker to reflect the effect of the drug, time-associated.

• Amount, sufficient amount of the biomarker to be detected by the adequate technique.

• Resemblance, the ability of the biomarker to give the same result independent of factors such as age, gender and ethnical background.

(44)

5.3 Biomarker Properties

To determine if a substance or metabolite is a suitable biomarker, some basic data about the drug has to be taken into consideration. In the following subsections, these data are presented for each drug. Only the main metabolites of each drug have been considered.

5.3.1 Ethanol

Ethanol blood concentration is usually defined as BAC, Blood Alcohol Concentra-tion.

Definition 5.5 (Blood Alcohol Concentration, BAC) The mass percent of

ethanol in the blood [49].

The blood is assumed to have a weight of 1.00 g/mL, resulting in that the grams of alcohol per gram blood equals the measure grams of alcohol per milliliter of blood [49].

Administration Route

The most common way of ethanol consumption is through the oral route [33].

Pharmacokinetics

Elimination of ethanol from the body occurs at a rate of approximately 0.015% BAC units per hour [49, 6]. Ethanol is water soluble, and distributes into tissues and fluids according to their water content [6] without binding to plasma proteins [78].

Dose

The amount of alcohol intake is hard to estimate, and can vary a lot. The blood alcohol limits for legal driving varies between the countries included in this project, ranging between 0.02–0.08 % BAC units. For country-specific limits see Appendix D.

Interpretation of Blood Concentration

Figure 5.2 shows the blood alcohol concentration in terms of time after consump-tion. The peak concentration of ethanol in the body depends on several factors, but can be approximated by the following formula:

Peak BAC [%] = Cf·_WN - 0.015T (females)

(45)

5.3 Biomarker Properties 25

where

N = the number of drinks (15 mL ethanol per drink) T = the time (hours) over which consumption took place W = the weight of the person (kg)

Cm= 1.7

Cf = 2.06

Figure 5.2. The three phases of the blood alcohol curve: absorption, distribution and

elimination [6].

The time when the peak ethanol blood concentration is reached depends on the amount of food present in the stomach and the alcoholic strength of the beverage. If ethanol is consumed on an empty stomach, the peak concentration is reached within 10–30 minutes, while 90–120 minutes is true for ethanol consumption in combination with food intake [93, 6].

When a measurable time passes by between consumption of drinks, metabolism of the first drink will be in progress before the absorption phase of the second drink is complete. Because of this, the second drink reaches its peak level by the time the effects of the first drink have begun to diminish, resulting in a total peak concentration lower than twice the peak concentration of one drink [49].

Duration of Effects

As illustrated in Figure 5.2, ethanol is rapidly absorbed into the bloodstream. The performance effects of ethanol are related to the blood alcohol concentration (Appendix C), and can be observed shortly after consumption. Elimination from the body occurs at a constant rate, that is to say, the duration of the elimination phase depends on the peak blood alcohol concentration [6].

(46)

Metabolism and Main Metabolites

The main metabolic pathways of ethanol are illustrated in Figure 5.3. Ethanol is metabolized along two different oxidative pathways, that mainly take place in the liver [93]. The first pathway is split into two steps, where the enzyme

alco-hol dehydrogenase converts ethanol into acetaldehyde. This reaction is followed

by the conversion of acetaldehyde to acetate, a reaction catalyzed by the enzyme

aldehyde dehydrogenase. In the second pathway, the ethanol metabolism follows

the microsomal ethanol oxidizing system, known as MEOS. This is a cytochrome P450-mediated pathway, a minor ethanol metabolizing pathway that transforms ethanol into acetaldehyde and further into acetate. Acetate is then further con-verted to acetyl-CoA [13].

A small fraction of ethanol follows two non-oxidative pathways, resulting in ethyl glucuronide and ethyl sulfate [63, 115].

Ethanol −→ Acetaldehyde

The active metabolite acetaldehyde is highly toxic and is therefore rapidly con-verted to acetate by the enzyme alcohol dehydrogenase. A large part of the free acetaldehyde molecules tends to react with cellular constituents like proteins, to form harmful acetaldehyde adducts [124, 76]. Altogether, this results in a low blood concentration of free acetaldehyde, less than 1% of the concentration of ethanol [63]. The protein-bound acetaldehyde might stay in the body for weeks [97, 10].

Some ethnic groups, for example up to 50% of all orientals, have a genetic poly-morphism resulting in low levels of aldehyde dehydrogenase. This leads to high levels of acetaldehyde in the body following ethanol consumption [124].

Acetaldehyde −→ Acetate

Acetate is not only a product of ethanol metabolism, it is also a part of the human diet [94]. Acetate is an active metabolite, and its blood concentration appears to be independent of blood ethanol concentration. The acetate levels in the body are only elevated as long as ethanol is metabolized, and the levels seem to be increased in persons who have developed metabolic tolerance to ethanol [63].

Acetate −→ Acetyl-CoA

Acetate is converted to acetyl-CoA by muscle and liver cells as well as other tis-sues [13, 6, 94]. Acetyl-CoA is also a metabolite of other substances in the body, such as glucose, and is therefore not specific for ethanol consumption [95]. This molecule is an important fuel molecule for the citric acid cycle, the final step in the generation of energy from food products in the cell. Besides energy, water and carbon dioxide are produced as end products of the ethanol metabolism [13]. Ethanol −→ Ethyl glucuronide (EtG)

The conversion of ethanol to EtG follows a non-oxidative pathway in the phase II metabolism [115]. EtG is a minor metabolite, with only 0.02% of the ethanol dose consumed excreted as EtG in the urine. EtG has been shown to reach higher

(47)

(48)

levels in urine than in blood, indicating that the blood levels are very low [65]. It is a non-volatile, water-soluble substance which can be detected for more than 70 hours after ethanol has been eliminated from the body [164].

The appearance of EtG is very specific for ethanol consumption, but not much is known about EtG kinetics in blood following ethanol administration. Only one study has evaluated the kinetics of EtG in blood, showing that EtG reaches de-tectable amounts in serum with a lag time of up to 45 minutes when compared to ethanol. Significant interindividual variations were found, and the peak concen-tration was reached as long as 3.5–5.5 hours after ethanol consumption. [65]. EtG has a half-life of 2–3 hours [164], and is thought to remain in the blood for up to 17 hours [65].

Factors such as the use of ethanol containing mouth wash and hand soap can in-crease the EtG levels in the body [121].

Ethanol −→ Ethyl sulfate (EtS)

The conversion of ethanol to EtS follows a non-oxidative pathway in the phase II metabolism [63, 115]. The formation of this metabolite has shown great interindi-vidual variations, which is thought to be explained by polymorphism in the genes, coding for the enzymes, responsible for EtS synthesis [59]. Less than 1% of the consumed ethanol is thought to be converted into EtS. This metabolite is specific for ethanol consumption, and has a detection window longer than that of ethanol [62].

Distribution Route

An overview of the distribution of ethanol in the body after oral administration is illustrated in Figure 5.4.

When ethanol is administrated orally, absorption takes place in the gastrointestinal tract, mainly the small intestine. This phase is referred to as the absorption phase, see Figure 5.2. The absorption rate is affected by numerous factors, such as the amount of ethanol consumed, the ethanol concentration of the beverage, and other contents of the GI tract. [49].

Once absorbed from the small intestine, ethanol enters the blood through the portal vein and is carried to the liver and then on to the heart and the lungs. Before the absorption phase is complete, the arterial blood ethanol concentration exceeds that of the venous. Because of its volatility, a fraction of the ethanol is emitted through the lungs, the principle used in alcolocks in use today [93]. After absorption, ethanol moves throughout the body and distributes in tissues and body fluids, a phase known as the distribution phase (Figure 5.2). Ethanol diffuses from the blood into tissues across capillary walls [124]. Since ethanol is water-soluble, the concentration depends on the amount of water. In general, regions with a high water content such as the saliva and the spinal fluid have a higher ethanol concentration than regions with a lower water content, such as the brain and the liver [93]. Men have a higher body water content than women (60% versus 50%), and as a consequence the ethanol blood concentration will be

(49)

Figure 5.4. The distribution of ethanol throughout the body after oral administration

[133]. The cross marks the gastrointestinal tract, through which ethanol enters the

circulatory system. The capillaries of the lower body perfuse the kidneys, while the capillaries of the upper body perfuse the brain.

(50)

higher (10–20%) in women [6]. The ethanol concentration equilibrates between blood water and total tissue water, although it might take a few hours before equilibrium is reached [124].

More than 90% of ethanol is eliminated through metabolism in the liver [93], while 5-10% is excreted, through the kidneys, as unchanged drug in the urine. A fraction of the ethanol is metabolized through first-passage metabolism in the stomach and the liver before absorption takes place. To a smaller extent, ethanol may be eliminated unchanged through saliva, expired air and sweat [93]. Altogether, this is referred to as the elimination phase (Figure 5.2).

The three phases described above take place at the same time, but the rate of each phase varies with time after ethanol consumption [6].

5.3.2 Marĳuana

Marĳuana constitutes of more than 400 different chemical compounds, making the metabolism of the drug difficult and hard to interpret. The main psychoactive component is ∆9-tetrahydrocannabinol, referred to as THC. THC is not specific for marĳuana, but is the active component of all psychoactive substances obtained from the Cannabis sativa plant [71]. THC is thought to have about 100 metabolites [75].

Administration Route

Marĳuana is usually smoked, even though oral administration is not uncommon [71].

Pharmacokinetics

A rapid absorption takes place after smoking marĳuana. THC can be measured in plasma within seconds, and peak THC plasma concentrations are reached within minutes. Oral administration leads to slower absorption, resulting in lower and delayed peak THC levels [33, 71]. Peak plasma concentrations are reached within 2–3 hours [71].

THC is highly lipophilic, and as much as 97–99% of THC is protein bound in blood, primarly to lipoproteins [71].

Dose

THC doses of up to 5 mg/day are typical therapeutic doses, while doses when used as a recreational drug are very variable. A single smoke intake from a marĳuana pipe or cigarette contains approximately 50 mg of THC [33].

Interpretation of Blood Concentration

The THC concentration in the body depends on the administrated dose as well as the pattern of use. Following smoking, peak plasma THC concentrations of 100–200 ng/mL are normally reached, and fall below 5 ng/mL within 3 hours [33].

(51)

In frequent users, both THC and its metabolites tend to accumulate, which com-plicates the determination of the the time of drug administration [71]. Plasma levels as low as 2 ng/mL might indicate recent use of marĳuana [87].

Intravenous administration of marĳuana results in higher peak plasma concentra-tions of THC compared to oral or inhaled marĳuana. The concentration of THC can not be directly related to the degree of impairment [71]. Even when the blood concentration has fallen below detectable limits, the user might still be affected by the drug [33].

A number of studies have proposed that either the THC concentration or the ratio between the concentrations of THC and the metabolite THC-COOH can be used to determine the time of marĳuana administration [72].

Duration of Effects

When marĳuana is smoked, the effects appear within minutes and the peak is reached within 10–30 minutes. A "high" is experienced by most marĳuana smok-ers, lasting for approximately 2 hours [33]. Intravenous or oral administration of marĳuana results in a slower onset of effects [71]. In the case of oral administra-tion, the effects are delayed with 0.5–2 hours, because of first-passage metabolism in the liver [7]. Within 3–6 hours after marĳuana administration, most behavioral effects return to normal [33, 71].

Metabolism and Main Metabolites

An overview of the main THC metabolic reactions can be seen in Figure 5.5.

Figure 5.5. The major metabolic route for THC [71].

∆9-THC −→ 11-hydroxy-∆9-tetrahydrocannabinol (11-OH-THC) Hydroxylation converts THC into the active metabolite 11-OH-THC. 11-OH-THC has a spectrum of action and a kinetic profile similar to that of THC [58]. When marĳuana is smoked, the concentration of 11-OH-THC reaches no more than 10% of the THC concentration. Following oral administration, on the other hand, the

Non-Invasive Methods for Detecting Drug and Alcohol Impaired Drivers : - a Study of Alcohol and Drug Biomarkers and Optical Detection Techniques

Institutionen för Fysik och Mätteknik

Examensarbete

Non-Invasive Methods for Detecting Drug and

Alcohol Impaired Drivers

Sarah Broberg and Elin Diczfalusy

Non-Invasive Methods for Detecting Drug and

Alcohol Impaired Drivers

Sarah Broberg and Elin Diczfalusy

Abstract

Sammanfattning

Acknowledgments

Acronyms and Abbreviations

Glossary

Contents

Chapter 1

Introduction

1.1

Volvo Car Corporation

1.2

Volvo Technology Corporation

1.3

Alcohol Detection at Volvo

1.4

Techniques Available Today

1.5

Background of this project

Chapter 2

Purpose and Research

Questions

2.1

Assignment

2.2

Purpose and Objective

2.3

Research Questions

2.4

Limitations

2.5

Method

2.6

Project Outline

Chapter 3

Substance Selection

3.1

Ethanol

3.2

Marĳuana

3.3

Methamphetamine/Amphetamine

3.4

Heroin/Morphine

3.5

Diazepam

Chapter 4

Effects of the Chosen

Substances

4.1

Ethanol

4.2

Marĳuana

4.3

Methamphetamine/Amphetamine

4.4

Heroin/Morphine

4.5

Diazepam

Chapter 5

Drug Metabolism and

Potential Biomarkers

5.1

Cell Metabolism

5.2

Biomarker Requirements

5.3

Biomarker Properties

5.3.1

Ethanol

5.3.2

Marĳuana