The synthesis, analysis and characterisation of piperazine based drugs

This study developed a GC-MS method for the simultaneous detection of piperazines and congeners in street samples of amphetamine type stimulants. This research investigated the clandestine routes of synthesis and chemical profiles of phenylpiperazines, represented by 1- (4-fluorophenyl)piperazine (4-FPP) and 1-(3-trifluoromethylphenyl)piperazine (3-TFMPP). These drugs are part of the increasingly prevalent illicit new psychoactive substances. The presence of (2, 3, 4) FPP and (2, 3, 4) TFMPP positional isomers has been identified by other researchers as a limitation due to their similar chemical profiles. The method was optimized and confirmed as compliant with the International Conference on Harmonisation and the Center for Drug Evaluation and Research guidelines on validation. 4- FPP and 3-TFMPP were synthesised using potential routes for clandestine laboratories. Simple extraction and analysis of 11 street samples was conducted using the method developed. Furthermore, the stability of 22 drugs during analysis was investigated. Limits of detection were in the range 5 – 1.95ng/mL free base on column. The synthesised samples were identified as 4-FPP and 3-TFMPP. Several impurities were observed in the synthesised samples, which were identified and categorised as residual reactants, isomers of 4-FPP and of 3-TFMPP and by-products of synthesis. The percentage yields of the synthesised samples obtained were up to 82.4% 4-FPP and 78.7% 3-TFMPP. The street samples were found to contain MDMA, 3-TFMPP, BZP, caffeine, ephedrine and other impurities. The analytical method simultaneously separates 19 of the most common drugs found in piperazine samples and achieves for the first time the GC-MS separation of (i) 2-FPP, 3-FPP and 4-FPP and (ii) 2-TFMPP, 3-TFMPP and 4-TFMPP at the same time from a sample matrix containing all the 19 compounds. This method provides operational laboratories with a more effective method for the chemical characterisation of street samples of piperazines and also provides novel stability data.