Introduction

Possession is not nine-tenths of the law - it's nine-tenths of the problem.

John Lennon

1.1 DRUG ABUSE

Drugs, whose possession or supply is restricted by law, are known as controlled or scheduled substances. They comprise both licit materials (i.e. those manufactured under licence for therapeutic use) and the illicit products of clandestine factories. Although many plant-based drugs have been self-administered for thousands of years (e.g. coca leaf, cannabis, opium, peyote cactus), the imposition of criminal sanctions is mostly a product of the 20th century. Many of the drugs currently abused were once not only on open sale, but often promoted as beneficial substances by the food and pharmaceutical industries. A pattern developed whereby initial misuse of pharmaceutical products such as morphine, cocaine and amphetamine led to increasing legal restrictions and the consequent rise of an illicit industry. Nowadays, nearly all serious drug abuse involves illicitly-produced substances. Most fall into just a few pharmacological groups, e.g. central nervous system stimulants, narcotic analgesics, hallucinogens (psychotomimetics) and hypnotics. It is still true that the most prevalent drugs are the plant-derived or semi-synthetic substances (e.g. cannabis, cocaine and heroin), but the view of the United Nations Drug Control Programme is that wholly synthetic drugs (e.g. amphetamine, MDMA and related designer drugs) are likely to pose a more significant social problem in the future. According to the World Health Organisation (WHO), scheduled drugs are 'abused' rather than 'misused', but in the following text the two terms are used synonymously. Drugs of abuse may or may not lead to physical or psychological 'dependence': a term used by WHO in preference to 'addiction'.

On the basis of a recent Home Office survey (Drug Misuse Declared in 2000 - see Bibliography), a third of the adult population in the United Kingdom (UK) admits to having used a controlled drug at least once in their lives; fewer than 10% use drugs on a regular basis and for the great majority of these the drug involved is cannabis. The next most common drugs are amphetamine, cocaine and 3,4-methylenedioxymethylamphe-tamine (MDMA). Seizure data from police and customs show a broadly similar pattern. There are currently over 100 000 arrests each year in the UK for drug offences, again the majority involving cannabis. In Europe, it is estimated that 0.2-0.3% of the population are regular heroin users. With few exceptions, the scale of drug abuse has steadily increased in most countries, but it is still predominantly associated with younger members of the population. Mortality from drug abuse has risen rapidly and is largely associated with opiates.

1.2 UK DRUG CONTROL LEGISLATION BEFORE 1971

Apart from the Pharmacy Act of 1868, which restricted the sale of opium, the modern period of drug control started in the early 20th century. Following the Poisons and Pharmacy Act 1908 and the Shanghai Opium Commission in 1909, further restrictions were introduced on cocaine, morphine and opium. More controls on a wider range of substances were introduced by the successive Dangerous Drugs Acts of 1920, 1925, 1951 and 1964. Synthetic amphetamine-like drugs entered the legislation in the Drugs (Prevention of Misuse) Act (DPMA) 1964, and a Modification Order in 1966 added lysergide (LSD) to the DPMA. The Dangerous Drugs Act 1965 consolidated previous legislation.

The first attempts to introduce structure-related generic control into UK drugs law were made with the DPMA of 1964. This contained a statement intended to cover a range of synthetic stimulants. The key feature was a definition of certain side-chain substitution patterns in α-methylphenethylamine (amphetamine) and β-methylphenethylamine. While this did indeed encompass compounds such as phentermine, methylphenidate and diethylpropion, it soon became clear that a refined interpretation of the generic statement unwittingly included dozens of drugs that were not stimulants. In fact, it could be argued that some barbiturates were also covered. This generic control was repealed by a Modification Order in 1970. Following this early failure, it would be some years before generic control of phenethylamines again entered the legislation. But this time (1977), the focus would be on ring-substituted phenethylamines, it would be much more robust and would be followed by generic controls for several other groups.

1.3 THE UNITED NATIONS CONVENTIONS

In international law, controls on drugs of abuse are set out in three United Nations (UN) treaties: The Single Convention on Narcotic Drugs 1961 (UN1961), the Convention on Psychotropic Substances 1971 (UN1971) and The Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances 1988 (UNI988). These treaties are implemented in domestic laws by signatory states, and have been considerably extended in some. In the UK, the corresponding legislation is the Misuse of Drugs Act 1971. Since the inception of the UN conventions, numerous substances have been added to the Schedules, particularly those of the 1971 treaty.

In the 1961 convention, there is a strong emphasis on plant-based drugs (i.e. cannabis, opium and cocaine), with rules for their cultivation, manufacture and trade. In addition, over 100 other substances, mostly synthetic narcotic analgesics, are included, but only a few of these are now used clinically or ever abused. More than 100 psychotropic substances are listed in the 1971 convention, but again only a small fraction is regularly abused. Unlike the treaty of 1961, there is no overarching control of the stereoisomers of psychotropic drugs. Thus in Schedule I, amphetamine, meaning both the (-) and the (+) enantiomers, is listed together with dexamphetamine [the (+) enantiomer of amphetamine] and levamphetamine [the (-) enantiomer] while methamphetamine, meaning the (+) enantiomer, is listed alongside methamphetamine racemate [a mixture of the (-) and (+) enantiomers]. These examples, and the situation whereby the stereochemical configuration of many other substances was left unspecified, has lead to some confusion, but the UN has recently moved to rationalise this matter. These problems have been avoided in the Misuse of Drugs Act by the inclusion of the stereo-isomers of almost all controlled drugs (see Chapter 3).

1.4 PRINCIPLES OF CURRENT UK LEGISLATION

The Misuse of Drugs Act 1971 replaced The Dangerous Drugs Act 1965 and the DPMA 1964 and introduced the concept of 'controlled drugs'. These are defined as those substances or products set out in Schedule 2. The Misuse of Drugs Act, which came into effect in 1973, set up an 'Advisory Council on the Misuse of Drugs' whose terms of reference include a statement of what might constitute a controlled drug. This is set out in Section 1(2) of the Act as: It shall be the duty of the Advisory Council to keep under review the situation in the United Kingdom with respect to drugs which are being or appear to them likely to be misused and of which the misuse is having or appears to them capable of having harmful effects sufficient to constitute a social problem. ...'.

The Misuse of Drugs Act prohibits certain activities with respect to controlled drugs (e.g. possession, possession with intent to supply, production) without a licence. With the exception of opium, there is no illegality in using or consuming a controlled drug. The great majority of arrests for offences under the Misuse of Drugs Act involve possession of relatively small amounts of a controlled drug. The drugs are listed in Schedule 2 of the Act and are divided into three Classes: Class A (Part I of Schedule 2), Class B (Part II) and Class C (Part III). These classes represent, in decreasing order A to C, the propensity of the substances to cause social harm. Associated with each class are the maximum penalties for offences involving controlled drugs, again decreasing in severity in the order A to C. For Class A drugs, the maximum penalty for some offences is life imprisonment, for Class B it is 14 years and for Class C, five years. A tariff of penalties has been established by the courts for a range of situations and some of these are described in Appendix 8. The list of substances in Schedule 2 may be varied by a Statutory Instrument known as a Modification Order. There have been 14 such Orders since 1971 (see Appendix 1), most of which have served to incorporate changes agreed by member states of the UN.

The details of control are legislated by 'regulations'. In the Misuse of Drugs Regulations 2001, which came into force on 1st February 2002 and replaced the previous Regulations of 1985, controlled drugs are divided into five schedules. The organisational principles of the Schedules in the Regulations are shown in Appendix 3. In simple terms, the Regulations set out what should be done with controlled drugs (i.e. their licit use) whereas the Act sets out what should not be done (i.e. their illicit use).

Many of the substances listed in the Misuse of Drugs Act and the Misuse of Drugs Regulations, numerous definitions and some parts of the generic controls derive directly from the UN conventions. However, the Misuse of Drugs Act goes beyond the minimum in several important areas. Not only are there more substances, but an important feature of the Act is the extensive use of structure-related generic terms. Because the Misuse of Drugs Act relies on the concept of actual or potential social harm, rather than the specific pharmacological or toxicological properties of a controlled drug, no great difficulty arises from the introduction of generic control. It is quite certain that amongst the essentially infinite number of generically-defined substances there will be compounds that have no abuse potential and some may have no physiological effect of any sort. Without these effects, a substance will not be marketed by the pharmaceutical industry and neither will it be produced as a misusable drug. The structure-related definitions discussed in Chapter 5 are found only in the Misuse of Drugs Act (and the Regulations) and closely-related legislation such as the Misuse of Drugs Act of the Republic of Ireland 1976, although similar concepts, differing only in detail, occur in the drugs legislation of New Zealand and parts of Australia.

Nearly all substances in the Act are chemically-defined entities. Although a number of controlled drugs are found in a variety of plants, the only 'vegetable' materials specifically controlled are coca leaf, opium, poppy-straw and its concentrate (all Class A) and cannabis and cannabis resin (both Class B, but see Chapter 9). A separate offence of cultivation also exists for these materials, although it is now common for cultivation to be subsumed under the broader offence of production of a controlled drug. There is a general reluctance to control too many botanical entities, partly because of taxonomic difficulties and partly because they may be seen as ubiquitous and naturally occurring.

Appendix 9 provides brief details of other legislation concerned with drug control. Apart from the Misuse of Drugs Act, the forensic scientist will have occasional need to consult the Medicines Act, 1968, perhaps to determine if a submitted drug is a prescription only medicine. However, the definition of a medicinal product in that Act has now been superseded (see Chapter 8). There are legal restrictions on the trade in certain substances used in the manufacture of drugs (so-called precursor chemicals), brief details of which are shown in Appendix 6.

1.5 EUROPEAN INITIATIVES

In June 1997, the Council of the European Union (EU) adopted a so-called 'Joint Action' on new synthetic drugs (NSD). This was concerned with information exchange on new substances as well as procedures for risk assessment and legal control. 'New synthetic drugs' were defined as those substances that had little or no therapeutic value and were not already under international control, but had a potential for abuse similar to those substances listed in Schedules I and II of the United Nations Convention on Psychotropic Substances 1971. The basis for this agreement was Article K.3 of the Treaty on European Union, signed at Maastricht, concerning the approximation of the laws and practices of the Member States of the European Union to combat drug addiction and to prevent and combat illegal drug trafficking. The Joint Action was promoted by the Dutch Government and it took place against a political background whereby Europe had become a leading producer of these drugs. Difficulties were emerging in the EU because of the way in which certain drugs were treated differently in different Member States.

The Joint Action was intended to focus attention on the plethora of 'designer drugs' (nearly all phenethylamines), which had appeared during the 1990s. A typical feature of NSD is that they are often presented in the form of white tablets bearing 'illicit' logos, which provide no clue to the chemical contents. Well-established drugs such as amphetamine, MDMA and its ethyl analogue (MDEA) were excluded since they were already controlled in international law.

Since 1997, of the several NSD reported in the EU, three (TV-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine [MBDB], 4-methylthioamphetamine [4-MTA] and para methoxymethylamphetamine [PMMA]) were selected for risk assessment by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA). The main elements of the risk assessment criteria were a chemical and pharmacological description of the NSD, acute and chronic psychological risks, sociological and criminological evidence, and public health risks. A recommendation was subsequently made that 4-MTA (4-methylthioamphetamine) should become a scheduled drug in all Member States. Although neither gamma-hydroxybutyrate (GHB) nor ketamine fall within the definition of an NSD, they were subjected to risk assessment by EMCDDA in 2000 because both are widely abused and neither is controlled under UNI971. No clear evidence emerged that either GHB or ketamine should be recommended for control in the EU, but the decision on GHB was overtaken by a meeting of the United Nations Commission on Narcotic Drugs (UN CND) in early 2001 where it was agreed that GHB should be brought under Schedule IV of UN1971 (see Chapter 9).

1.6 ABBREVIATIONS

In some publications, the abbreviation MDA is used for the Misuse of Drugs Act 1971, but this is not ideal because MDA is also the common acronym for 3,4-methylenedioxyamphetamine: one of the 'Ecstasy' drugs. In this book, the Misuse of Drugs Act 1971 is referred to as the 'Act'. The Misuse of Drugs Regulations, 2001 are shown as the 'Regulations'. Substances listed in Schedule 2 to the Act are correctly known as 'controlled drugs', but, for the sake of clarity and when the context is clear, are often described herein simply as 'drugs' or 'substances'. By normal convention, the abbreviation 'mg' is used in the following text for milligram(s). It may be noted that, until the 2001 revision, the Regulations used the obsolete term milligrammes.

Schedule 2 to the Act

The following tables and subordinate text are set out with paragraph headings as they appear in Schedule 2 to the Act. Class A controlled drugs are included in Part I of Schedule 2, Class B in Part II and Class C drugs in Part III. Substances or products, which are listed in UN1961 or UNI 971, are indicated along with the corresponding Schedule of the Regulations (see also Appendices 3 to 5). Where a substance or generic definition was introduced into the Act by a subsequent Modification Order (see Appendix 1), the corresponding Statutory Instrument Number (S.I.) and date are shown.

Generic Controls: Miscellaneous

3.1 SALTS

The salts of all controlled drugs are also controlled to the same degree as the parent. A salt is the product of reacting a base with an acid. Like many physiologically active chemicals, controlled drugs are mostly bases, often described as nitrogenous bases or, for plant-derived bases, sometimes termed alkaloids. For various reasons, including stability and ease of handling, the salts (especially hydrochlorides, sulfates and phosphates, less commonly organic anions such as tartrates) are more often seen in both commercial and illicit products than the parent substances. Structures 3.1 and 3.2 show two examples of the formation of salts.

Acidic drugs are uncommon; the best examples amongst controlled drugs are the barbiturates. Reaction of a 5,5-disubstituted barbituric acid with sodium hydroxide (a base) produces the sodium salt (see Structure 3.3).

It is not usually necessary for the forensic chemist to identify whether a questioned substance is in its free form (base or acid) or as a particular salt but the need could arise if a case concerned salt-base conversion such as the production of cocaine base (crack) from cocaine hydrochloride (see Appendix 7).

3.2 ESTERS AND/OR ETHERS

3.2.1 Introduction

The esters and ethers of Class A substances and of the anabolic/andro-genic steroids in Class C are subject to the same controls as their unmodified parents, unless that ester or ether is already specified elsewhere in Schedule II. Only structures with a hydroxyl (-OH), sulfhydryl (-SH) or a suitable acid (e.g. carboxylic -COOH) group commonly form esters, and only hydroxyl and sulfhydryl groups commonly form ethers. Amongst those basic drugs listed in the Act, which are able to form an ester or an ether, only the hydroxyl function is found.

3.2.2 Esters

An example of ester formation is the conversion of morphine to diamorphine (the diacetyl ester of morphine) as shown in Structure 3.4. This process is used, for example, in the illicit production of heroin (crude diamorphine). Diamorphine slowly hydrolyses in damp conditions or rapidly in aqueous alkaline solutions to produce 6-monoacetyl morphine (Structure 3.5). Monoacetylmorphine is still an ester of morphine and therefore remains a Class A controlled drug.

Another example of an ester is psilocybin, the naturally-occurring phosphate of psilocin (Structure 3.6). Both psilocin and psilocybin are found in certain fungi of the Psilocybe genus (so-called magic mushrooms; see Chapter 8).