Abstract
The aim of the study was to provide baseline data on the pharmacological properties of heroin available for retail sale in Cabramatta, Sydney. A retrospective sampling frame was constructed consisting of all suspected heroin seizures in Cabramatta between October 1996 and March 1997 ( n = 487). A total of 33 street-level 'exhibits', comprising 88 samples, were selected. Ion chromatography was used to determine whether heroin was present as the free base or as the hydrochloride (or other salt). High performance liquid chromatography with diode array detection was used to assess the presence of diacetylmorphine hydrochloride (heroin hydrochloride), O-6-monoacetylmorphine hydrochloride (degradation product) and acetylcodeine hydrochloride (synthesis byproduct). Gas chromatography/mass spectrometry and high performance liquid chromotography with refractive index detection were used to detect adulterants and diluents. All samples contained heroin as the hydrochloride salt. No heroin free base was encountered. The mean purity was 66% with 85% of samples having an average purity of at least 50%. The samples were free of harmful adulterants. Adulterants detected were pharmacologically inactive diluents largely used to add bulk (sugars) or pharmacologically active adulterants used to improve the bioavailability of heroin HCL when smoked (caffeine). Results have implications for attempts to reduce drug-related harms and, in particular, suggest that interventions designed to facilitate transitions from heroin injecting to smoking require careful consideration of the pharmacological factors associated with route of administration.