II.2.8 Phencyclidine by Akira Ishii and Yoshinao Katsumata
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2.8 II.2.8 Phencyclidine by Akira Ishii and Yoshinao Katsumata Introduction Phencyclidine ( PCP) (> Fig. 8.1), a synthetic arylcyclohexylamine hallucinogen, had been fi rst applied as an anaesthetic to animals and then to humans for a short period. PCP is known by street names of “ angel dust” and “ crystal”. Illicit use of PCP fi rst appeared during mid-1960s along the West Coast, and then peaked in the United States in 1979; illicit PCP use declined by 1992. However, daily use of PCP has remained stable among young school seniors over the past decade; PCP is thus being an important drug of abuse [1–3]. It is being regulated as a subclass compound of narcotics and stimulants (DEA Class II). PCP in both antemortem and postmortem specimens is being analyzed by immunoassays [4–9], GC [10–13], GC/MS [14–18], GC/MS/MS [19, 20], HPLC [21] and CE [22]. In this chapter, a detailed procedure for simple GC/MS analysis of PCP in blood and urine is pre- sented. ⊡ Figure 8.1 Structures of PCP and pethidine (IS). Reagents and their preparation i. Reagents PCP hydrochloride and pethidine (meperidine) hydrochloride (internal standard, IS) can be purchased from Sigma (St. Louis, MO, USA) with suitable legal documentation. Bond Elut Glass columns are obtained from Varian (Harbor City, CA, USA). Other chemicals to be used are of analytical grade. © Springer-Verlag Berlin Heidelberg 2005 242 Phencyclidine ii. Preparation • PCP and pethidine solutions: the compounds are separately dissolved in appropriate amounts of methanol; a 10–20 µL aliquot is spiked into 1 mL of a whole blood or urine specimen. • 1 M NaHCO3 solution: 8.4 g of NaHCO3 is dissolved in distilled water to prepare 100 mL solution. • Chloroform/methanol (9:1, v/v): a 100-mL volume of the mixture is prepared. GC/MS conditions GC columna: a FactorFour VF-5ms fused-silica capillary column (30 m × 0.25 mm i. d., fi lm thickness 0.25 µm, Varian, Harbor City, CA, USA). GC conditions; instrument: a Varian CP-3800 gas chromatograph with a split-splitless in- jector (Walnut Creek, CA, USA); column (oven) temperature: 100 °C (1 min)→ 20 °C/min→ 300 °C; injection temperature: 250 °C; carrier gas: He; its fl ow rate: 1.0 mL/min; injection: splitless mode for 1 min, followed by the split mode (split ratio: 50). MS conditions; instrument: a Varian Saturn 2000 ion-trap tandem mass spectrometer b connected with the above GC; ionization: positive ion EI; electron energy: 70 eV; emission cur- rent: 10 A; multiplier off set: 230 V; detector voltage: 1.6 kV; scan time: 0.6 s; transfer tempera- ture: 240 °C; manifold temperature: 45 °C; trap temperature: 210 °C. Procedure [18] i. To 1 mL of whole blood or urine specimen containing PCP, are added 100 ng of pethidine (IS, methanolic solution) and 8 mL distilled water, followed by mixing well. For a whole blood specimen, it is necessary to confi rm the complete hemolysis. A 1-mL volume of 1 M NaHCO3 solution is added to the above mixture to bring its pH to about 8. ii. A 10-mL volume of methanol and 10 mL distilled water are passed through a Bond Elut Glass column to activate it. Th is procedure is repeated at least twice. iii. Th e above mixture is loaded onto the column, and the column is washed with 20 mL dis- tilled water. iv. PCP and IS are slowly eluted with 3 mL of chloroform/methanol (9:1) into a glass vial. v. A small amount of upper aqueous layer is carefully removed by aspiration with a Pasteur pipette. Th e organic layer (chloroform) is evaporated to dryness under a stream of nitro- gen. Th e residue is dissolved in 50 µL methanol; a 2-µL aliquot of it is injected into GC/MS being operated in the mass chromatographic mode. vi. Combined ions at m/z 242 plus 200 are analyzed for PCP and those at m/z 246 plus 232 plus 218 are analyzed for IS from 4 to 12 min of retention time. vii. A calibration curve is constructed by adding various concentrations of PCP and 100 ng IS to the vials containing 1 mL of blank whole blood or urine and 8 mL distilled water each, followed by the above procedure. Th e number of diff erent concentrations of PCP should not be smaller than 4. Th e calibration curve is composed of PCP concentration on the horizontal axis and peak area ratio of PCP to IS on the vertical axis. Th e peak ar- ea ratio of a test specimen is applied to the calibration curve to calculate its concentra- tion. Phencyclidine 243 ⊡ Table 8.1 EI mass spectra of PCP and pethidine (IS) Compound m/z (% peak intensitiy) PCP 200 (100) 242 (84) 84 (24) 91 (18) 186 (13) IS 246 (100) 71 (98) 172 (84) 232 (63) 218 (46) Assessment of the method > Table 8.1 shows EI mass spectra of PCP and IS. In this method, combined ions at m/z 242 ([M–1]+) plus 200 and those at m/z 246 ([M–1]+) plus 232 plus 218 are used for PCP and IS, respectively. Th e mass chromatograms of PCP and IS are shown > Fig. 8.2. Th e detection limit (S/N = 3) was about 5 ng/mL for PCP. According to NIDA guidelines, the cutoff level of PCP in urine samples is 25 ng/mL. Th e toxic concentrations of PCP in blood were reported to be 7–240 ng/mL; the fatal blood levels were 1–5 µg/mL [23]. Th us, the present meth- od can be suffi ciently applicable for detection and quantitation of toxic levels of PCP in blood. Th e recoveriy of PCP using the Bond Elut Glass column was about 100 % for whole blood [18]. ⊡ Figure 8.2 Mass chromatograms for PCP and pethidine (IS) extracted from whole blood. In this system, ions at m/z 200 plus 242 (PCP) and at m/z 246 plus 232 plus 218 (IS) were used at the retention time of 4–12 min. The amounts of PCP and IS spiked into 1 mL blank whole blood were 25 and 100 ng, respectively. Poisoning case, and toxic and fatal concentrations A 28-year-old white man [24], who had had a history of drug abuse, exhibited bizarre behav- ior on an airline fl ight; he was transferred to the University of California, San Diego Medical 244 Phencyclidine Center. At admission, he stared straight ahead, following commands but not responding verbally; the levels of serum creatinin kinase and aspartate aminotransferase were more than 100-times the normal limits. On hospital day 2, he became rigid, diaphoretic and had a temperature reaching 39.2 °C; he was treated for neuroleptic malignant syndrome. On day 4, the serum PCP concentration reached 1,879 ng/mL, the highest level during the course. On day 8, he required intubation due to respiratory failure; his temperature increased to 41.4 °C. On day 11 (13 days aft er ingestion), he was found to pass two plastic bags through his rectum; one bag had been ruptured. He had probably swallowed the two plastic bags contain- ing PCP powder, one of which had been ruptured to cause the PCP poisoning. On hospital day 12, he made a rapid neurologic recovery; he was discharged with clear consciousness on day 24. A similar case of protracted coma, caused by an intestinal deposit containing PCP, was also reported; the highest PCP concentration in serum reached 1,690 ng/mL [25]. A fatal PCP poisoning case associated with hypertensive crisis [26], and two sudden death cases during arrest associated with PCP poisoning [27] were reported. Th ree death cases, resulting from the PCP use, were reported in Los Angeles County, 1976; PCP concentrations in blood and the liver ranged from 2.0 to 19.0 µg/mL and from 1.7 to 32.7 µg/g, respectively [28]. Cravey et al. reported nine PCP-related deaths; the concentrations in blood and the livers ranged from 0.3 to 12 µg/mL (average: 2.4 µg/mL) and from 0.9 to 80 µg/g (average: 20.1 µg/g), respectively [29]. Notes a) Any capillary column of 5 % phenylsiloxane/95 % dimethylsiloxane stationary phase can be used, regardless of manufacturers; but GC/MS grade columns are recommendable. b) Any modern type of GC/MS instruments can be used. Th e present instrument can be used as a GC/MS/MS system; the better selectivity can be obtained in the tandem mode. 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J Anal Toxicol 16: 381–388 7) Sneath TC, Jain NC (1992) Evaluation of phencyclidine by EMIT® d.a.u.™ utilizing the ETS® analyzer and a 25-ng/ mL cutoff.