Phencyclidine: Detection and measurement of toxic precursors and analogs in illicit samples

The contamination of illicit phencyclidine (PCP) by the carbonitrile precursor piperidinocyclohexanecarbonitrile (PCC) is a likely possibility. Since several other PCP derivatives have been identified in street samples, the authors measured the toxicity of PCP, the pyrrolidine derivative (PCPY), the morpholine derivative (PCM), and their respective carbonitrile precursors in the mouse. The toxicities of the carbonitrile precursors were consistently greater than the parent compounds with relative potencies (precursor vs parent) ranging from 1.27-7.88 for the precursors. Corresponding analytical methods were devised for the detection and measurement of these carbonitrile precursors in the presence of the parent compounds in street samples. PCC contamination of PCP could be detected as low as 1% (weight basis) by chemical ionization mass spectrometry (CI-MS). The quantitative measurement of PCC and PCP in street samples was made by gas chromatography (GC) using a nitrogen detector. As little as 0.5% PCC contamination could be measured by this technique. These methods were found to be equally applicable for the detection of other PCP analogs and their respective precursors. A group of eleven PCP street samples obtained from local authorities was analysed by CI-MS and GC. The PCP was detected in one sample (2%). Two additional derivatives of PCP also were identified. Based on toxicity data in the mouse, it is suggested that illicit street samples contaminated with the carbonitrile precursors would be considerably more toxic than PCP alone and pose a greater threat to the health of subjects ingesting these substances.