|Minor differences at microscopic level can produce substances very similar in effect to prohibited drugs of dependence, but that aren’t specifically listed in any of the schedules of the Drugs, Poisons and Controlled Substances Act 1981. Provisions in various state and Commonwealth legislation prohibit these copycats so that their possession and sale is illegal even if a few molecules have been added or removed from a substance’s chemical structure.
In Daley v Tasmania  TASCCA 4 the Tasmanian Court of Criminal Appeal rejected the appellants’ assertion that the term derivative should be interpreted narrowly. The chemical structure of 4-methylmethcathinone (or mephedrone) was held to be a derivative of methcathinone, even though the prosecution hadn’t proved one substance had come from the other. This decision may have relevance to Victorian cases, where the inclusive definition of drug of dependence refers to derivatives, but not analogues as the Commonwealth legislation does.
Uncertainty over the classification of drugs according to their chemical composition is a recurring problem. It arose with the description of cannabis in Hardy v Gillette  VicRp 36;  VR 392, and with hallucinogens in McEwen v R (1998) 99 A Crim R 421 more recently.
In Daley v Tasmania  TASCCA 4 the substance concerned was methcathinone, also known as meow meow. More about this substance, as well as a discussion of the interplay between relevant Victorian and Federal law, can be found in the Drug analogues post from last year.
3-D composition of 4-methyl-methcathinone
In Tasmania, the Misuse of Drugs Act 2001 (Tas) has a provision at cl 1(c) of Schedule 1 that reads (in part),
(c) a reference to a substance includes —
(i) that substance prepared from natural sources or artificially; and
(ii) every salt, active principle or derivative, including esters and ethers, and every salt of such an active principle or derivative; and
(iii) every alkaloid of the substance and every salt of such an alkaloid; and
(iv) except where the substance is levomethorphan or levorphanol, every stereo-isomer of the substance and every salt of the stereo-isomer; and
(v) a preparation or admixture containing any proportion of the substance.
The term derivative is not further defined there. The term also appears in our Drugs, Poisons and Controlled Substances Act 1981 (Vic) at s 4(d) and e(ii), broadening the definition of drug of dependence.
In Daley v Tasmania  TASCCA 4, the appellants maintained at their trial and again on their appeal that the substance involved, 4-methylmethcathinone, was not a derivative of methcathinone. (The first chemical structure was not listed in the Schedule at the time of the alleged offence; the second was).
It was decided as a preliminary question that it was open to the jury to be satisfied that 4-methylmethcathinone was a derivative of methcathinone: Tasmania v Daley and Shipp  TASSC 43.
Comparisons of chemical structure, reproduced from the judgment of Evans J in Tasmania v Daley and Shipp
Expert evidence was received on the voir dire from both parties about the technical meaning of the term derivative and the chemical composition of the two substances in question, as well as the relationships between other drugs contained in the schedule. It was agreed between experts that the term derivative in modern usage refers to a substance which is produced through a process from a pre-existing substance. An older usage (now commonly referred to as a structural analogue) is where a substance bears a resemblance to another, but is not necessarily the product of a chemical process. Evans J preferred the latter interpretation as more consistent with the purpose of the Act, and concluded [at 20 and 21]:
For these reasons I conclude that the meaning of derivative when used in relation to chemicals encompasses both the concept of a substance made from another and the concept of a substance that is structurally related to another, but that the meaning should be qualified so as to exclude such an association that is no more than theoretical. I conclude that derivative means a substance or compound that can readily be made from another substance or compound, as well as a substance or compound that is closely related structurally to another substance or compound.
The meaning of a term used in legislation to describe a drug as being within a proscribed category is a question of law. Once the meaning is determined, the further question of whether a particular substance falls within that meaning is a question of fact for the jury, Reid v Kerr (1974) 9 SASR 367, Wells J, at 376, and Yager v McQueen (1977) 139 CLR 28, at 33–34, and 44–45. On the evidence before me there is a great degree of similarity between the chemical structures of 4-methylmethcathinone and methcathinone. Accordingly there is simply no issue that the former can be (and indeed is) a derivative of the latter. If there was disagreement about whether 4-methylmethcathinone is closely related structurally to methcathinone, then that issue would need to be determined by a jury.
At the trial subsequently presided over by Crawford CJ, the jury found the substance was a derivative. On the appeal, the Court of Criminal Appeal found that Evans J had decided the legal meaning correctly. (If this case was decided before DPP (C’th) v Coory  VSCA 316 it’s possible that the confusion surrounding that sentencing hearing would have been avoided).
Blow, Porter and Wood JJ [at 25]:
In our view, the modern narrow construction urged upon us by counsel for the appellants would not promote the purpose or object of the Act, but the wide old-fashioned construction adopted by Evans J and Crawford CJ does promote the purpose or object of the Act. The long title of the Act is “An Act to prohibit the misuse of drugs and activities associated with the misuse of drugs and for related purposes”. As Evans J pointed out in the passage quoted above, the narrow construction could result in the legislation being circumvented by the manufacture of analogues of prohibited drugs that have similar properties but are not prohibited. It is clear, when one considers cl 1(c) as a whole, that Parliament was seeking to promote the objective of prohibiting the misuse of drugs by prohibiting activities not just in relation to the substances enumerated in the relevant schedule, but to all sorts of similar substances, including salts, esters, ethers and derivatives. It follows that a wide interpretation of the word “derivative” would promote the purpose or object of the Act, whereas a narrow construction would not. It is possible that some analogues of some controlled drugs might be harmless but, in our view, that possibility does not detract from that conclusion.
Effectively, the Tasmanian Court of Criminal Appeal applied to the term derivative the meaning that the Commonwealth legislation (and elsewhere) has given to analogue.
In Coory  VSCA 316 the Victorian Court of Appeal commented [at 8 and 46] that it would be desirable for the legislature to adopt the term analogue into the Drugs Act and avoid the confusion. Certain chemicals are prescribed as precursor chemicals, prohibited if possessed in certain quantities and without appropriate licences by s 71D of the Act. The list is found in the Drugs, Poisons and Controlled Substances (Precursor Chemicals) Regulations 2007, and is constantly changing.