Glossary

Terms in bold italics are themselves defined.

Active pharmaceutical ingredient (API)

The substance in a medicinal product that is biologically active.

Addiction

For most purposes, addiction is synonymous with dependence.

Adulterant

Often synonymous with cutting agent. A substance added as a diluent to a drug. It may be inert or pharmacologically active. Such diluents can be found in illicit powders as well as tablets, in which case the term might also include tablet binders.

Affinity constant

The equilibrium dissociation constant, expressed as a K_i value, used in drug-receptor binding to describe how tightly a ligand (drug) binds to a particular receptor. Ligand-receptor affinities are measured in molar units (M), which correspond to the concentration of ligand at which the binding site of a particular receptor is half occupied. The smaller the constant, the more tightly bound the ligand is, and the higher the affinity between ligand and receptor.

Agonist

A drug that mimics the effect of neurotransmitters or other endogenous molecules. It has the opposite effect to an antagonist.

Alkali

Usually, an inorganic base such as sodium hydroxide or sodium carbonate. By combining with the chemically-bound acid residue, an alkali is used, for example, to convert a salt into the free base.

Alkaloid

A naturally-occurring nitrogenous base.

Aluminium foil method

A type of reductive amination that requires little equipment. A precursor ketone (e.g., P2P, PMK) is reacted in ethanol with aluminium metal pieces, an amine and a mercuric chloride catalyst. When the amine is methylamine and the ketone is PMK then the product is MDMA.

Amine

A chemical group comprising a nitrogen atom attached to one or more carbon atoms and one or more hydrogen atoms. Amines are typically bases.

Analgesic

A substance that reduces the sensation of pain. Also known as an analgetic. See also narcotic analgesic.

Analogue

A substance whose structure is related to that of another, but whose chemical and biological properties may be quite different. Sometimes used to mean derivative.

Analogue control

The inclusion in legislation of a definition that covers a family of substances. It is less specific than generic control and may be based on the concept of ‘similarity in chemical structure’ as well as ‘similarity in pharmacological activity’ to the parent substance.

Antagonist

An agent that opposes the action of another (the opposite of agonist).

Base

A nitrogenous substance, sometimes known as an alkaloid when derived from plant material, which reacts with acids to form a salt. Many bases are insoluble in water but soluble in organic solvents.

Bioisostere

A compound resulting from the exchange of an atom or of a group of atoms with another, broadly similar, atom or group of atoms. The objective of a bioisosteric replacement is to create a new compound with similar biological properties to the parent compound.

Cannabimimetic

A synthetic substance that has similar properties to THC, i.e., it interacts with the CB₁ receptor usually as an agonist. Also known as cannabinomimetic. The preferred term now is synthetic cannabinoid receptor agonist.

CB₁ receptor

A cannabinoid receptor primarily located in the CNS. THC behaves as an agonist at the CB₁ receptor, which is then responsible for the psychoactive effects. Other cannabinoid receptors, such as CB₂, are found mainly in the immune system, and are partly involved in the perception of pain.

CBD

Cannabidiol (CBD) is one of several phytocannabinoids in Cannabis sativa. It has anti-psychotic and anti-convulsant effects and occurs at a higher concentration in cannabis resin than in herbal cannabis. In some strains of intensively produced cannabis, with a high THC content, the CBD level may be extremely low.

CBN

Cannabinol (CBN) is a phytocannabinoid and an oxidation product of THC. It is normally only found in aged samples of cannabis and cannabis resin.

CNS

Central nervous system.

Cutting agent

A substance added as a diluent to a drug. It may be inert or pharmacologically active. Such diluents can be found in illicit powders as well as tablets where the term might also include tablet binders. Often synonymous with adulterant.

Dependence

Drug dependence is a psychiatric disorder and a complex neurobiological phenomenon, whereby repeated use leads to increasing difficulty in stopping. The term has been used by the World Health Organization (WHO) in preference to addiction.

Diastereoisomers

In the simplest case, when a molecule contains two centres of asymmetry, it can form four diastereoisomers (i.e., two pairs of enantiomers). Thus ephedrine, for example, exists as four diastereoisomers, two of which are known as pseudoephedrine.

Dopamine

An example of a neurotransmitter, it is a naturally-occurring substituted phenethylamine. Substances that interact with the dopamine receptor are said to be dopaminergic.

Drug

A substance presented for treating, curing or preventing disease in human beings or in animals. It may also be used for making a medical diagnosis or for restoring, correcting, or modifying physiological functions.

Drug Abuse

The use of a pharmacologically-active substance for non-medicinal purposes.

Drug Misuse

For most purposes, drug misuse is synonymous with drug abuse, but it can also imply abuse of a substance which has a legitimate medicinal use, whereas drug abuse could be used more generally.

Ecstasy

Originally used to describe MDMA, but since generalised to describe a wide range of substituted phenethylamines and, less precisely, certain unrelated substances.

Empathogen

A substance that produces empathy with others, most often applied to MDMA and related drugs. See also entactogen.

Enantiomer

One of a pair of stereoisomers arising from the presence in a molecule of an asymmetric carbon atom. The two enantiomers are mirror images of each other, with left- and right-handed forms denoted S (sinister) and R (rectus) respectively. Enantiomeric pairs may be denoted by the symbols (+) and (−) or previously by the terms d and l.

Entactogen

A substance that produces a socialising effect and desire for contact, most often applied to MDMA and related drugs. See also empathogen.

Ergoline

A tetracyclic molecule ultimately derived from the ergot fungus. It contains a molecular sub-unit that is effectively a rigidified tryptamine. The most common ergoline is lysergide (LSD).

Euphoriant

A substance that induces an emotional condition in which a person experiences intense feelings of well-being, elation and happiness.

Generic control

The inclusion in legislation of a definition that covers a family of substances. At one level this includes esters or ethers of a parent molecule – an example that derives from the 1961 UN Single Convention on Narcotic Drugs. More elaborate generic definitions are based on substitution patterns in a parent molecule where the type, number and position of substituents may be precisely specified. A consequence of generic control is that it may subsume substances with varied pharmacological activity or even none at all. The generic approach should be contrasted with analogue control.

Hallucinogen

A substance that produces, as a main effect, perceptual distortions, especially visual and auditory. The term is somewhat misleading as some so-called hallucinogenic substances do not cause true hallucinations (i.e., sensory perceptions in the absence of external stimuli). The term hallucinogen is often now used for substances that were once described as psychedelic, psychotomimetic or psychodysleptic.

Homologue

When a series of chemical compounds differ only by a constant structural element, they are said to form a homologous series.

Hydrate

Some salts contain water chemically bound within their crystalline structure; these are referred to as hydrates.

Hypnotic

A substance that induces sleep.

Illicit drug

Strictly refers to a substance that has not been formally licensed as a medicine. The term is widely used in a more general sense to mean a drug without therapeutic use or a drug that has been produced under clandestine circumstances.

INN

International Non-Proprietary Name. Defined by the World Health Organization (WHO) for substances that have or have had therapeutic value.

IUPAC

International Union of Pure and Applied Chemistry. A body responsible for the systematic nomenclature of chemical entities.

Leuckart route

A popular method for converting ketones (e.g., P2P and PMK) to the corresponding amines using formic acid, ammonium formate or formamide/methylformamide as reagents. When the ketone is P2P, the result is amphetamine or methylamphetamine, while MDA and MDMA arise from the ketone PMK.

Mass spectrum

A pattern of charged molecular fragments produced by bombarding molecules with electrons. The fragmentation pattern is characteristic of the molecule.

Narcotic

In older literature (the ‘UN 1961 Single Convention on Narcotic Drugs’ and the ‘International Narcotics Control Board’ are prime examples), the term narcotic was once used to mean what would now be described as a psychoactive substance.

Narcotic analgesic

A type of analgesic acting on the central nervous system rather than on peripheral nerves. Many opioids and opiates (e.g., diamorphine) are typical narcotic analgesics.

Neurotransmitter

A chemical messenger involved in passing a signal from one neuron to adjacent neurons in the brain. These include serotonin, dopamine, glutamate and γ-aminobutyric acid (GABA).

Nitrogenous base

A synthetic or naturally-occurring substance containing one or more amine nitrogen atoms in its structure and acting as a base.

Noradrenaline

Also known as norepinephrine and an example of a neurotransmitter that is a naturally-occurring substituted phenethylamine. Substances that interact with the noradrenaline receptor are said to be noradrenergic.

Opiate

An opiate is a substance derived from opium. Opium alkaloids include morphine, papaverine, thebaine etc, but it also includes the semi-synthetic derivatives of those alkaloids such as diacetylmorphine and codeine.

Opioid

An opioid is a substance that has not been derived from opium, and may be structurally unrelated to morphine, but has similar properties, i.e., a narcotic analgesic. However, the term opioid is sometimes used to include opiates.

Opium

The dried latex of the seed capsule of the opium poppy (Papaver somniferum L.).

P2P

1-Phenyl-2-propanone: a ketone often used as a precursor to amphetamine and methylamphetamine. Also known as phenylacetone and benzylmethylketone (BMK).

Phenethylamine

Phenethylamine is 2-phenylethylamine. The term is used less precisely to mean a derivative of phenethylamine, often by substitution in the side-chain or in the aromatic ring or both. The phenethylamine family includes a range of substances that may be stimulants, entactogens or hallucinogens.

Phytocannabinoid

One of a group of compounds found only in Cannabis sativa including cannabidiol (CBD), cannabinol (CBN) and tetrahydrocannabinol (THC). Commonly abbreviated to cannabinoid and distinct from synthetic cannabinoid receptor agonist.

PMK

Piperonylmethylketone, a ketone often used as a precursor in the manufacture of MDMA. Also known as 3,4-methylenedioxyphenyl-2-propanone.

Potency

A quantitative measure of the activity or strength of a drug: a different concept to purity, which is the proportion of active drug in a preparation.

Primary amine

A chemical group comprising a nitrogen atom attached to two hydrogen atoms and to a carbon atom.

Psychoactive drug

A substance that affects the mind or mental processes. The term is often used in a broad sense to include both psychotropic and narcotic drugs. This term is preferred to older, less common, expressions such as psychodysleptic and psychotomimetic.

Psychotropic drug

A generic term for substances that modify normal behaviour. It includes inter alia, stimulants, hallucinogens, tranquillisers, hypnotics. In the UK at least, the preferred term is psychoactive drug.

Purity

The proportion (%) of active drug in a preparation: a different concept to potency. Most laboratories determine purities with respect to the base because in a sample sent for analysis, the particular salt form cannot be determined without further, often unnecessary, investigation. For example, pure amphetamine base has a purity defined as 100%. When amphetamine base reacts with e.g., sulfuric acid to form the sulfate salt, then the purity of that salt, with respect to the base, is 73%; the remaining 27% is the sulfate residue. If the purity is expressed with respect to a specific salt form, then pure amphetamine sulfate has a purity of 100%.

R-Enantiomer

See enantiomer

Racemate, also Racemic mixture

A 50 : 50 mixture of two enantiomers produced when a synthesis is not stereoselective.

Reclassification

The process of moving a substance from one Class to another in the (UK) Misuse of Drugs Act, and the legislation of certain other countries.

Reduction

A chemical process involving removal of oxygen atoms and/or addition of hydrogen atoms.

Reductive amination

A chemical process involving removal of oxygen atoms and addition of amino groups.

S-Enantiomer

See enantiomer

Salt

The product of reacting a base with an acid. Many salts are soluble in water but poorly soluble in organic solvents.

Secondary Amine

A chemical group comprising a nitrogen atom attached to a hydrogen atom and two carbon atoms.

Serotonin

Also known as 5-hydroxytryptamine, it is an example of a neurotransmitter. It is a naturally-occurring substance closely related to synthetic hallucinogenic tryptamines.

Stereoisomer

One of two or more forms of a molecule with the same sequence of atoms, which arises from the three-dimensional arrangement of those atoms.

Stimulant

A substance that increases psychomotor activity, often by increasing the production of certain neurotransmitters in brain synapses.

Synthetic Cannabinoid Receptor Agonist (SCRA)

A synthetic substance that interacts with, for example, the CB₁ receptor for the endogenous substance anandamide and produces similar effects to THC.

Tautomerism

Tautomers are isomers of organic compounds that readily interconvert by a chemical bond rearrangement called tautomerism. This commonly results in the migration of a hydrogen atom, accompanied by a switch of a single bond and an adjacent double bond.

Tertiary amine

A chemical group comprising a nitrogen atom attached to three carbon atoms but bearing no hydrogen atoms.

THC

Δ⁹-Tetrahydrocannabinol, the major active principal in cannabis. The International Non-Proprietary Name (INN) is dronabinol.

Tryptamine

Tryptamine itself is 1H-indole-3-ethanamine, but the term is also used less precisely to mean a derivative of tryptamine, often by substitution at the side-chain nitrogen atom or in the aromatic ring or both. The tryptamine family includes numerous hallucinogens and/or substances that interact with serotonin receptors.