Phencyclidine concentrations in postmortem body fluids and tissues

In vitro and in vivo metabolism and detection of 3-HO-PCP, a synthetic phencyclidine, in human samples and pooled human hepatocytes using high resolution mass spectrometry

The new psychoactive substance (NPS) 3-HO-PCP, a phencyclidine (PCP) analog, was detected in a law enforcement seizure and in forensic samples in Denmark. Compared with PCP, 3-HO-PCP is known to be a more potent dissociative NPS, but no toxicokinetic investigations of 3-HO-PCP are yet available. Therefore, 3-HO-PCP was quantified in in vivo samples, and the following were investigated: plasma protein binding, in vitro and in vivo metabolites, and metabolic targets. All samples were separated by liquid chromatography and analyzed by mass spectrometry. The unbound fraction in plasma was determined as 0.72 ± 0.09. After in vitro incubation with pooled human hepatocytes, four metabolites were identified: a piperidine-hydroxyl-and piperidine ring opened N-dealkyl-COOH metabolite, and O-glucuronidated- and O-sulfate-conjugated metabolites. In vivo, depending on the sample and sample preparation, fewer metabolites were detected, as the O-sulfate-conjugated metabolite was not detected. The N-dealkylated-COOH metabolite was the main metabolite in the deconjugated urine sample. in vivo analytical targets in blood and brain samples were 3-HO-PCP and the O-glucuronidated metabolite, with 3-HO-PCP having the highest relative signal intensity. The drug levels of 3-HO-PCP quantified in blood were 0.013 and 0.095 mg/kg in a living and a deceased subject, respectively. The 3-HO-PCP concentrations in deconjugated urine in a sample from a living subject and in post-mortem brain were 7.8 and 0.16 mg/kg, respectively. The post mortem results showed a 1.5-fold higher concentration of 3-HO-PCP in the brain tissue than in the post mortem blood sample.

Inhibition of g protein-activated inwardly rectifying k channels by phencyclidine

Addictive drugs, such as opioids, ethanol, cocaine, amphetamine, and phencyclidine (PCP), affect many functions of the nervous system and peripheral organs, resulting in severe health problems. G protein-activated inwardly rectifying K⁺ (GIRK, Kir3) channels play an important role in regulating neuronal excitability through activation of various Gi/o protein-coupled receptors including opioid and CB₁ cannabinoid receptors. Furthermore, the channels are directly activated by ethanol and inhibited by cocaine at toxic levels, but not affected by methylphenidate, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA) at toxic levels. The primary pharmacological action of PCP is blockade of N-methyl-D-aspartate (NMDA) receptor channels that are associated with its psychotomimetic effects. PCP also interacts with several receptors and channels at relatively high concentrations. However, the molecular mechanisms underlying the various effects of PCP remain to be clarified. Here, we investigated the effects of PCP on GIRK channels using the Xenopus oocyte expression system. PCP weakly but significantly inhibited GIRK channels at micromolar concentrations, but not Kir1.1 and Kir2.1 channels. The PCP concentrations effective in inhibiting GIRK channels overlap clinically relevant brain concentrations in severe intoxication. The results suggest that partial inhibition of GIRK channels by PCP may contribute to some of the toxic effects after overdose.

Phencyclidine and violent deaths in St. Louis, Missouri: a survey of medical examiners' cases from 1977 through 1986

A survey of 104 deaths involving phencyclidine (PCP) occurring from 1981 through 1986 in metropolitan St. Louis, Missouri, is presented. Four black males (22-33 yr) died from fatal PCP intoxication. PCP was detected in an additional 100 deaths: 81 homicides, 13 suicides, and 6 accidental deaths. Seventy-five of these deaths were homicides of Black males (mean age 27 years) typically dying from gunshot wounds, 64 cases. In 50% of deaths where PCP was detected, other drugs were co-administered: ethanol (35%) and cocaine (20%) being the most common mixtures. A dramatic continuous increase in PCP abuse from 1984 through 1986 was demonstrated by drug abuse indicator data: treatment admissions, emergency room episodes, police exhibits, and driving under the influence of PCP arrests. Increased abuse of PCP in St. Louis has been associated with increased medical emergencies and violence against persons.

Drugs of abuse found in fatally injured drivers in Los Angeles County

Blood or urine specimens from nearly 600 fatally injured drivers in two Los Angeles County studies were analyzed for the presence of alcohol and other drugs of abuse, including PCP, cocaine, opiates and marijuana. The results of the preliminary study indicate that 65 out of 102 fatally injured drivers had used alcohol and/or another drug of abuse - 34 had used alcohol only, 12 had used one or more other drug(s) of abuse, and 19 had used alcohol in combination with another drug of abuse. The results of the larger follow-up study, begun a year later, indicate a continued high level of both alcohol use (41.5%) and marijuana use (19%) with moderate cocaine usage (8%) and low levels (less than 2%) of barbiturate and PCP usage.