Effects of filtration on the presence of particulate and oxycodone content of injections prepared from crushed OxyContin® tablets.

It is common for injecting drug users (IDU) to prepare injections by crushing tablets which are not designed for parental administration. The injection of insoluble tablet excipients can lead to serious local and systemic medical complications. The aim of the study was to investigate the effectiveness of various types of filters in removing harmful insoluble particles from the injections prepared using crushed oxycodone tablets. Injections were prepared from a sustained-release oxycodone tablet formulation. The filtration of tablet extracts was carried out following procedures used by IDU using makeshift filter and commercially available filters. Particulate contamination and oxycodone content were analysed using light microscopy and spectrophotometer. Unfiltered extracts contained hundreds of thousands of particles of sufficient size to cause harms. Cigarette filters removed large particles but failed to remove small particles. The combination of cigarette filter and syringe filter (0.45 µm or 0.22 µm) reduced the particle count by 90 - 95%. A double membrane syringe filter (0.8/0.2 µm) removed more than 99% of the particles. Recovery of oxycodone was more than 95% with the tested syringe filters. Particulate contamination in injections prepared from crushed tablets can be effectively removed using a combination process of cigarette filter and syringe filters, or a 0.8/0.2 µm syringe filter. Compared to other filters, the 0.8/0.2 µm syringe filter did not block, the filtration was quick and easy to perform, and did not retain oxycodone. The use of a 0.8/0.2 µm syringe filter can provide an important harm reduction measure for IDU.

Effect of filtration on morphine and particle content of injections prepared from slow-release oral morphine tablets.

BACKGROUND: Injections of mixtures prepared from crushed tablets contain insoluble particles which can cause embolisms and other complications. Although many particles can be removed by filtration, many injecting drug users do not filter due to availability, cost or performance of filters, and also due to concerns that some of the dose will be lost. METHODS: Injection solutions were prepared from slow-release morphine tablets (MS Contin) replicating methods used by injecting drug users. Contaminating particles were counted by microscopy and morphine content analysed by liquid chromatography before and after filtration. RESULTS: Unfiltered tablet extracts contained tens of millions of particles with a range in sizes from < 5 microm to > 400 microm. Cigarette filters removed most of the larger particles (> 50 microm) but the smaller particles remained. Commercial syringe filters (0.45 and 0.22 microm) produced a dramatic reduction in particles but tended to block unless used after a cigarette filter. Morphine was retained by all filters but could be recovered by following the filtration with one or two 1 ml washes. The combined use of a cigarette filter then 0.22 microm filter, with rinses, enabled recovery of 90% of the extracted morphine in a solution which was essentially free of tablet-derived particles. CONCLUSIONS: Apart from overdose and addiction itself, the harmful consequences of injecting morphine tablets come from the insoluble particles from the tablets and microbial contamination. These harmful components can be substantially reduced by passing the injection through a sterilizing (0.22 microm) filter. To prevent the filter from blocking, a preliminary coarse filter (such as a cigarette filter) should be used first. The filters retain some of the dose, but this can be recovered by following filtration with one or two rinses with 1 ml water. Although filtration can reduce the non-pharmacological harmful consequences of injecting tablets, this remains an unsafe practice due to skin and environmental contamination by particles and microorganisms, and the risks of blood-borne infections from sharing injecting equipment.