The role of citric acid Jenny Scott PhD MRPharmS Lecturer in Pharmacy Practice University of Bath

Transcription

1 The role of citric acid Jenny Scott PhD MRPharmS Lecturer in Pharmacy Practice University of Bath

2 Structure of this presentation Background Experimental aims Methods Results Conclusions & further possible investigations

3 Background Most street heroin in the UK is in base form 1. Base heroin has very poor solubility (1:1700) 2 To prepare solutions for administration injecting drug users (IDUs) convert the drug to a soluble form 3

4 How street heroin is prepared for injection 4 : Put drug onto teaspoon + Add acidifier Add water & stir Filter into syringe Heat

5 If the diamorphine content of the street heroin is accurately known, the quantity of pure acidifier (e.g. citric acid) needed to convert all the diamorphine base to soluble salt can be predicted. 1 mole of diamorphine (369.40g) requires moles of citric acid (70.03g)

6 Citric and the outbreak : early speculation At the early stages of the outbreak ( ) data from those affected and/or friends and relatives suggested: there was a link in the source of heroin there may be a common source of citric acid ( Raja culinary citric acid) the quantity of citric acid needed to dissolve the heroin was much greater than normal

7 Experimental aims Prepare injections with heroin from the case simulating the methods used by IDUs to: Illustrate how much Raja citric acid was needed to dissolve the heroin compared to usual Establish how acidic the prepared injections were Give injections prepared with the suspect heroin and used filters for further analysis if required

8 Methods Four 10 bags of heroin of the type implicated in the outbreak were supplied by Strathclyde Police (SP) Raja citric acid was supplied by SP Injections were prepared using the laboratory method developed by J. Scott in previous work 4,5.

9 Injection preparation method used in the lab Tip heroin from bag onto metal teaspoon (weigh bag full & empty) Add citric acid (X mg) Add 0.8 ml water boiled and cooled from kettle Mix with tip of needle sheath Heat over flame until mixture bubbles. Expect heroin to dissolves & liquid to go clear Draw through a piece of Rizla+ Extra filter tip into 1ml syringe Transfer syringe contents into glass vial

10 Measurements & calculations Weight of heroin tipped onto spoon calculated Based on 60% purity figure from SP, diamorphine content estimated Quantity of citric acid needed predicted as 9.10 mg, approximate quantity added (1 st experiment only). Observe spoon contents for satisfactory dissolution. Increase amount of citric acid added on basis of observed result. ph of resulting injection measured with small probe ph meter

11 Results Exp 1 Exp 2 Exp 3 Exp 4 Wt of heroin (mg) 73.83* Amount of citric added Comment on injection Most solid did not dissolve Most solid did not dissolve Some solid remained Most solid dissolved ph * Based on 60% purity, diamorphine content approx 44 mg

12 Conclusions & further possible investigations To obtain satisfactory dissolution of heroin approximately six times the predicted amount of citric acid was necessary. Reason? The dissolved injection (experiment 4) had a low ph (3.01) which may have contributed to muscle irritation and damage but unlikely to cause the extensive tissue necrosis seen in cases Prepared injections and used filters were made available for further recommended analysis (mass spec and microbiology) Advice of microbiologists was recommended

13 Acknowledgements Thanks to Glasgow University Dept Toxicology References 1. KING, L.A. (1997). Drug content of powders and other illicit preparations in the UK. Forensic Science International. 85: PARFITT, K., Martindale: The complete drug reference. 32nd Ed. London: Pharmaceutical Press. 3. WILLS, S., Drugs of Abuse. London: The Pharmaceutical Press 4. SCOTT, J. et al, (2000). Laboratory study of the effects of citric and ascorbic acids on injections prepared with brown heroin. International Journal of Drug Policy. 11(6): SCOTT, J. (2000). Development, Implementation and Evaluation of Harm Reduction Techniques for Drug Users. PhD Thesis. The Robert Gordon University, Aberdeen.