When does the cutting of cocaine and heroin occur? The first large-scale study based on the chemical analysis of cocaine and heroin seizures in Switzerland (2019)

Background: Illicit drug profiling can provide knowledge about illicit drug markets, informing on the level of distribution and its evolution in space and time. Illicit drug profiling is usually limited to impurities originally present in the illicit drug (e.g. alkaloids, co-extracted compounds or by-products). However, the benefit of a comprehensive analysis of cutting agents in drug seizures for law enforcement agencies, intelligence and health policy has not been thoroughly investigated in the literature and is the focus of this research.
Aim: This research aims at assessing when and how cutting (i.e. adulteration and dilution) occurs in the supply chain by analysing cocaine and heroin seizures made between 2006 and 2015 in Switzerland.
Methods: Cocaine and heroin seizures made along the supply chain by law enforcement agencies in the Western region of Switzerland were investigated for adulteration and dilution. A total number of 7841 cocaine and 3476 heroin specimens coming from 1341 and 721 seizures, respectively, were analysed.
Results: The results show that, for both illicit drugs, adulteration and/or dilution occur before arrival into Switzerland as well as in Switzerland. While cocaine is adulterated and diluted, heroin is only adulterated. Interestingly, the same mixture of adulterants (i.e. caffeine-paracetamol) is used to cut heroin at each step in the supply chain.
Conclusion: Gaining knowledge about adulteration and dilution at different stages in the supply chain enhances our understanding of drug markets. It also highlights differences along the supply chain and in the distribution of both drugs in Switzerland.