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Pharmacology of drugs in saliva , Phencyclidine

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  p180-181

2026-10-10

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Pharmacology of drugs in saliva

Phencyclidine

PCP has low protein binding in plasma (<10%) and a pKa of 9.43. From the Henderson–Hassel balch equation, the saliva: plasma ratio is expected to be greater than unity. After giving oral (1mg) and intravenous (0.1 or 1mg) doses of radiolabelled PCP to healthy male volunteers, Cook et al.(1982a) reported that the parent drug was found in saliva at concentrations higher than would be expected from the pH differential between plasma and saliva and the binding of the drug in plasma and saliva. The saliva: plasma ratio ranged from 1.5 to 3.0. Saliva was collected by expectoration into glass vials, and saliva pH averaged 6.7±0.17.

PCP is primarily abused by smoking tobacco or marijuana cigarettes that have been dipped into PCP-containing solvents. Inhaled PCP is trapped in the tissues of the mouth. Cook et al. (1982b) also reported both PCP and Phen cyclohexene (PC) were present in plasma after volunteers smoked 100lg of radiolabelled PCP. The persistence of PCP or PC in saliva after smoking PCP was not reported. McCarron et al. (1984) analysed paired serum and saliva samples from 100 patients suspected of PCP intoxication. Both serum and saliva tests were positive for PCP by radioimmunoassay (RIA) in 70 of the cases, and both were negative in seven cases. In 21 cases with no clinical evidence of PCP intoxication, both serum and saliva RIA were negative in 17 cases, and positive in three cases. Saliva PCP concentrations ranges from 2 to 600 lg/L. The proposed US workplace cut-off for PCP in saliva is 10 lg/L PCP equivalents by immunoassay and the confirmation cut-off is 10 lg/L PCP (SAMHSA 2000).