Quantification of Phencyclidine (PCP) in Urine, Serum, or Plasma by Gas Chromatography-Mass Spectrometry (GC-MS)

Phencyclidine (PCP), a dissociative anesthetic, is a commonly abused recreational drug. In the 1950s, initially tested as an intravenous anesthetic, PCP was discontinued for clinical use due to its severe adverse effects. Since then, it has gained popularity as a recreational drug due to its ability to induce hallucinations and alter perception. PCP can be detected in urine, serum, or plasma by immunoassays and quantified and its presence confirmed by gas or liquid chromatography-mass spectrometry. In the method described here, a deuterated internal standard is added to the sample and the drug is extracted under alkaline conditions. Analysis is conducted using gas chromatography-mass spectrometry (GC-MS). Selected ion monitoring is used for quantitation of PCP.

Intoxication with 3-MeO-PCP alone: A case report and literature review

RATIONALE

3-Methoxyphencyclidine (3-MeO-PCP) is a new psychoactive substance derived from phencyclidine. Although it can lead to severe intoxications, the main manifestations and optimal management have not been well characterized. Here, we report 2 cases of 3-MeO-PCP intoxication in the same patient, and summarize the manifestations of this intoxication reported in literature.

PATIENT CONCERNS

A 17-year-old male purchased a bag of 3-MeO-PCP on the Internet but took an oral dose (200 mg) that corresponds to the less active isomer 4-MeO-PCP. He developed high blood pressure (158/131 mm Hg), tachycardia (100 bpm), and neurological manifestations (confusion, hypertonia, nystagmus, and then agitation). A maculopapular rash appeared, although this may have been related to the administration of midazolam. Hyperlactatemia (2.6 mmol/L) was the main laboratory finding. Seven days later, he returned to the emergency department after sniffing 50 mg of 3-MeO-PCP. High blood pressure, tachycardia, and neurological manifestations (psychomotor impairment and dysarthria) were present but less severe than after the first intoxication.

DIAGNOSIS

In the first intoxication, the blood and urine 3-MeO-PCP concentrations were, respectively, 71.1 ng/mL and 706.9 ng/mL. Conventional toxicity tests were all negative. In the second intoxication, biological samples were not available.

INTERVENTIONS

In the first intoxication, treatment consisted of intravenous hydration and midazolam. The patient was transferred to an intensive care unit for monitoring. After the second intoxication, he was monitored for 12 hours.

OUTCOMES

The patient's condition improved quickly in both cases.

LESSONS

These cases provide additional information on the manifestations of 3-MeO-PCP intoxication. These manifestations are mainly cardiovascular (high blood pressure, tachycardia) and neurological. The fact that second (50 mg) intoxication was less severe than the first (200 mg) is suggestive of a dose-effect relationship for 3-MeO-PCP. The first case also emphasizes the risk of dosing errors caused by the similarity between the names "3-MeO-PCP" and "4-MeO-PCP."

Quantitation of phencyclidine (PCP) in urine and blood using gas chromatography-mass spectrometry (GC-MS)

Phencyclidine (PCP) is a cycloalkylamine and is classified as a dissociative anesthetic. In the 1950s, PCP was tested as an intravenous anesthetic but due to its severe side effects, it was withdrawn from the clinical use. Since then PCP has become an illegal street drug making its laboratory analysis forensically essential. PCP can be detected in urine, serum, or plasma by immunoassays and quantified by gas or liquid chromatography mass spectrometry. In the method described here, a deuterated internal standard is added to the sample and the drug is extracted under alkaline conditions. Analysis is conducted using gas chromatography mass spectrometry (GC-MS). Quantitation of PCP is done by comparing the responses of unknown samples to the standards using selected ion monitoring.

New designer drugs N-(1-phenylcyclohexyl)-2-ethoxyethanamine (PCEEA) and N-(1-phenylcyclohexyl)-2-methoxyethanamine (PCMEA): Studies on their metabolism and toxicological detection in rat urine using gas chromatographic/mass spectrometric techniques

Studies are described on the metabolism and the toxicological detection of the phencyclidine-derived designer drugs N-(1-phenylcyclohexyl)-2-ethoxyethanamine (PCEEA) and N-(1-phenylcyclohexyl)-2-methoxyethanamine (PCMEA) in rat urine using gas chromatographic/mass spectrometric (GC/MS) techniques. The identified metabolites indicated that PCEEA and PCMEA were transformed to the same metabolites by N-dealkylation and O-dealkylation partially followed by oxidation of the resulting alcohol to the respective carboxylic acid and hydroxylation of the cyclohexyl ring at different positions and combinations of those. Finally, aromatic hydroxylation of the O-dealkylated metabolites was partially followed by hydroxylation of the cyclohexyl ring at different positions. All metabolites were partially excreted in conjugated form. The authors' systematic toxicological analysis (STA) procedure using full-scan GC/MS after acid hydrolysis, liquid-liquid extraction and microwave-assisted acetylation allowed the detection of an intake of a common drug users' dose both of PCEEA and PCMEA in rat urine. Assuming similar metabolism in humans, the STA should be suitable for proof of an intake of PCEEA and PCMEA in human urine, although their differentiation is not possible due to common metabolites.

Simultaneous Determination of Multiple Drugs of Abuse and Relevant Metabolites in Urine by LC-MS-MS

A method was developed for the quantitative analysis of 30 drugs of abuse and their metabolites in urine, including opiates, barbiturates, amphetamines, cocaine, cannabinoids, phencyclidine, methadone, and benzodiazepines. This method uses solid-phase extraction (SPE) on an Oasis HLB column followed by liquid chromatography-tandem mass spectrometry. Analytes were quantified by multiple reaction monitoring with the deuterated analogues as internal standards, using an atmospheric pressure ionization-electrospray interface. The method was validated by examining specificity, precision, accuracy, linearity, recovery, reproducibility, and detection limits. The limits of detection ranged from 9 pg/mL to 2.29 ng/mL in urine depending on the analyte. The SPE procedure was automated on a RapidTrace workstation to increase analytical throughput, and the results obtained via automated SPE were compared to those obtained by manual SPE to examine carryover effect, precision, accuracy, recovery, and reproducibility. To evaluate method performance, 108 urine samples were collected anonymously and tested for the presence of these drugs.

Analytic Performance of Immunoassays for Drugs of Abuse Below Established Cutoff Values

Background: The analytic performance and accuracy of drug detection below Substance Abuse and Mental Health Services Administration (SAMHSA) cutoffs is not well known. In some patient populations, clinically significant concentrations of abused drugs in urine may not be detected when current SAMHSA cutoffs are used. Our objectives were to define the precision profiles of three immunoassay systems for drugs of abuse and to evaluate the accuracy of testing at concentrations at which the CV was <20%.

Methods: Drug-free urine was supplemented with analytes to assess the precision in three commercial drugs-of-abuse immunoassay systems below the SAMHSA-dictated cutoffs for amphetamines, opiates, benzoylecgonine, phencyclidine, and cannabinoids. Consecutive urine samples with signals associated with a CV <20% by Emit® immunoassay and below SAMHSA cutoffs were then subjected to confirmatory analysis.

Results: The CV of all immunoassay systems tested remained <20% to drug concentrations well below SAMHSA cutoffs. The accuracy of urine drug-screening results between the SAMHSA-specified cutoffs and the precision-based cutoffs was less than accuracy for specimens above the SAMHSA cutoffs, but the use of the precision-based cutoff produced a 15.6% increase in the number of screen-positive specimens and a 7.8% increase in the detection of specimens that yielded positive results on confirmatory testing.

Conclusion: The precision of three commercial immunoassay systems for drugs-of-abuse screening is adequate to detect drugs below SAMHSA cutoffs. Knowledge of the positive predictive values of screening immunoassays at lower cutoff concentrations could enable efficient use of confirmatory testing resources and improved detection of illicit drug use.

Massive Venlafaxine Overdose Resulted in a False Positive Abbott AxSYM®Urine Immunoassay for Phencyclidine

CASE REPORT

A 13-yr-old girl overdosed on 48 x 150 mg venlafaxine (Effexor XR). She was taking venlafaxine regularly for depression. Her only other medications included topical Benzamycin and pyridoxine 50 mg daily for acne. The Abbott AxSYM assay was positive only for phencyclidine, but GC/MS did not confirm the presence of phencyclidine. Toxilab identified only one substance, confirmed by GC/MS as venlafaxine. A serum sample obtained 3 h after her ingestion revealed a venlafaxine concentration of 24460 ng/mL and an O-desmethylvenlafaxine concentration of 3930 ng/mL, confirming the massive acute overdose (therapeutic range of venlafaxine and O-desmethylvenlafaxine together is 250-750 ng/mL). Urine spiked with 4.2 mg/mL ofvenlafaxine and 0.7 mg/mL of O-desmethylvenlafaxine was interpreted as positive with the Abbott AxSYM fluorescent polarized immunoassay for phencyclidine (readout of 28 ng/mL).

CONCLUSION

Venlafaxine may cause a false positive Abbott AxSYM phencyclidine assay when present in very high concentrations. Physicians should be aware of this potential reaction when interpreting urine drug immunoassays.

[Solid-phase microextraction for the analysis of drugs and biological samples]

Solid-phase microextraction (SPME) as a new sample pretreatment technique was developed in 1990s. The applications of SPME on drugs and biological samples are reviewed with 60 references. The references were classified into twelve groups according to the character of analysis.

Application of solvent microextraction to the analysis of amphetamines and phencyclidine in urine

A fast and simple method to detect some commonly abused illicit drugs, amphetamine, methamphetamine, 3,4-methylendioxy-amphetamine (MDA), 3,4-methylendioxy-methamphetamine (MDMA), 3,4-methylendioxy-N-ethylamphetamine (MDEA) and phencyclidine (PCP) in urine using solvent microextraction (SME) combined with gas chromatography (GC) analysis has been developed. The extraction is conducted by suspending a 2 microl drop of chloroform in a 2 ml urine sample. Following 8 min of extraction, the organic solvent is withdrawn into the syringe and injected into a GC with a pulsed discharge helium ionization detector (PDHID). The effects of different extraction solvents and times, pH and sample preparation were studied. The optimized method was capable of detecting drugs in urine at concentrations below Substance Abuse and Mental Health Services Administration (SAMHSA) established cut-off values for preliminary testing. Good linearity and reproducibility of extraction were obtained. The limits of detection were 0.5 microg/ml for amphetamine, 0.1 microg/ml for methamphetamine and MDA, 0.05 microg/ml for MDMA, 0.025 microg/ml for MDEA and 0.015 microg/ml for PCP. Relative standard deviation (R.S.D.) values ranged between 5 and 20% for the studied drugs.

Comparison of ELISAs for opiates, methamphetamine, cocaine metabolite, benzodiazepines, phencyclidine, and cannabinoids in whole blood and urine

BACKGROUND

ELISAs are widely utilized in forensic drug analysis. A comparative assessment of microtiter plate assays for the detection of six common classes of drug in blood and urine is described.

METHODS

ELISAs for opiates, methamphetamine, benzodiazepines, cocaine metabolite, phencyclidine (PCP), and tetrahydrocannabinol (THC) metabolite were evaluated in a side-by-side study. The analytical performance of 12 commercially available ELISAs was determined in terms of binding characteristics, dose-response curves, limits of detection, sensitivity, intra- and interassay imprecision, and lot-to-lot reproducibility. Assay performance was also compared using 855 forensic casework samples.

RESULTS

Detection limits in whole blood for morphine, D-methamphetamine, nordiazepam, benzoylecgonine, nordiazepam, PCP, and L-11-nor-9-carboxy-delta9-THC were 3, 2, <4, 5, 25, and 3 microg/L, respectively, for the STC ELISAs. Corresponding detection limits for Immunalysis ELISAs were <1, <2, <4, 5, <1, and 1 microg/L, respectively. Intraassay CVs (n = 8) at the immunoassay cutoff concentrations were 4.1-5.6% and 3.5-11% for STC and Immunalysis ELISAs, respectively. Corresponding interassay CVs were 3.1-10% and 6.5-20%. Of the 855 casework samples, there were a total of 92 discordant results (44 cannabinoid, 15 opiate, 15 methamphetamine, 11 benzodiazepine, and 7 cocaine metabolite). Gas chromatography-mass spectrometry analysis indicated a total of three unconfirmed positive results for Immunalysis assays and one unconfirmed positive for STC assays.

CONCLUSIONS

A comparative assessment of drugs-of-abuse assays from two manufacturers indicated some key differences in analytical performance. Overall, Immunalysis assays offered superior binding characteristics and detection limits, whereas STC assays offered improved overall precision and lot-to-lot reproducibility.

SPEC disc solid-phase extraction for rapid broad-spectrum drug screening in urine

Broad-spectrum drug screening requires that all relevant substances be isolated, detected, and identified, regardless of their structure and/or polarity. To this end, systematic solid-phase extraction (SPE) approaches for drug isolation from biological fluids are required. Because speed and cost effectiveness are key issues in analytical toxicology, we have evaluated a disc-format extraction device for this purpose and compared the latter with an existing packed-bed column-format method. The discs were SPEC.PLUS.C18AR/MP3 cartridges with 10-mL solvent reservoirs, providing hydrophobic and cation exchange interactions. Blank human urine was spiked at 2 microg/mL with a selection of acidic, neutral, and basic drugs representing a variety of relevant drug classes. Urine specimens (2 mL) were diluted with 2 mL 0.1 M phosphate buffer (pH 5.0) and then applied to the preconditioned disc. Washing was done with 1 mL water. Acidic and neutral drugs were eluted with 1 mL ethyl acetate/acetone (1:1), and basic drugs were eluted with 1 mL ammoniated ethyl acetate. The eluates were collected separately, evaporated down to about 0.1 mL, and analyzed by gas chromatography-flame-ionization detection to check cleanliness, recoveries, and reproducibilities. The discs showed good extraction properties for all drugs and were easy to handle. Recoveries were 75-100% with coefficients of variation of around 5%. The resulting eluates showed only a few matrix interferences. As compared to our standard SPE method with packed-bed columns, the disc procedure allowed reductions in elution volumes and total processing time of approximately 60-65%.

1-[1-(2-Benzo[b]thiopheneyl)cyclohexyl]piperidine hydrochloride (BTCP) yields two active primary metabolites in vivo. Identification and quantification of BTCP primary metabolites in mice plasma, urine, and brain and their affinity for the neuronal dopamine transporter

1-[1-(2-Benzo[b]thiopheneyl)cyclohexyl]piperidine hydrochloride (BTCP) and cocaine bind to the neuronal dopamine transporter (DAT) to strongly inhibit dopamine (DA) reuptake. Although similar to acute administration, cocaine and BTCP produce sensitization and tolerance, respectively, on chronic administration. We previously found that liver microsomes produced two primary metabolites from BTCP with a high affinity for DAT. Because such metabolites, if produced in vivo, could account for the pharmacological difference with cocaine, it was important to compare BTCP biotransformations in vitro and in vivo. Therefore, we identified and quantified BTCP and primary metabolites in mice urine, plasma, and brain after acute i.p. administration. The low recovery yield suggest that BTCP might behave like its close analogue, phencyclidine, with long-term storage of metabolites. Two active metabolites found in vitro were found in mice brain with estimated half-life values similar to that of BTCP ( approximately 0.3 h). Although respective brain concentrations were 20 and 40 times lower than that of BTCP, their potency to displace in vivo [3H]BTCP bound to the DAT was 50 and 10 times higher, respectively, than that of BTCP. They could, therefore, contribute to the inhibition of DA transport and play an important role in BTCP pharmacology. They could also explain the differences between BTCP and cocaine on repeated administration.

Pharmacokinetic mechanisms for obtaining high renal coelimination of phencyclidine and a monoclonal antiphencyclidine antigen-binding fragment of immunoglobulin G in the rat

Our purpose was to determine mechanisms and methods for significantly increasing the renal coelimination of phencyclidine (PCP) and an anti-PCP monoclonal antibody binding fragment (anti-PCP Fab). To accomplish this goal, we performed a series of experiments to examine the dose-dependence of Fab elimination, mechanisms for enhancing PCP and Fab urinary coelimination and the antigenicity of repeated Fab administration. The results showed that urinary elimination of PCP and anti-PCP Fab was linear over a 30-fold range of doses. Anti-PCP Fab serum pharmacokinetics were best described using bi- or tri-exponential curves with a terminal elimination half-life of approximately 8 hr. Nevertheless, under all experimental conditions the early, nonterminal phase(s) were responsible for the majority (60%) of intact Fab elimination, with only 40% of the Fab eliminated during the terminal phase. These data suggest that the early rapid decline in Fab serum concentrations was primarily due to passive filtration and excretion of intact Fab, and not due to extravascular distribution as previously described. In comparison of methods for enhancing renal coelimination of Fab and PCP, systemic alkalinization produced a significant increase in Fab urinary elimination, with 69% of the Fab dose and 41% of the PCP dose recovered intact in the urine. Finally, in studies of the antigenicity of Fab, repeated administration of Fab produced no significant immune response or renal impairment. Overall, these experiments suggest that careful attention to the physiological status of the kidney during early time periods is essential for maximum coelimination of Fab and bound chemicals.

Determination of five abused drugs in nitrite-adulterated urine by immunoassays and gas chromatography-mass spectrometry

The adulteration of urine specimens with nitrite ion hasseen shown to mask the gas chromatography-mass spectrometry (GC-MS) confirmation testing of marijuana use. This study was designed to further investigate the effect of nitrite adulteration on the detection of five commonly abused drugs by immunoassay screening and GC-MS analysis. The drugs tested are cocaine metabolite (benzoylecgonine), morphine, 11-nor-delta-tetrahydrocannabinol-9-carboxylic acid (THCCOOH), amphetamine, and phencyclidine. The immunoassays evaluated included the instrument-based Abuscreen ONLINE assays, the on-site Abuscreen ONTRAK assays, and the one-step ONTRAK TESTCUP-5 assay. Multianalyte standards containing various levels of drugs were used to test the influence of both potassium and sodium nitrite. In the ONLINE immunoassays, the presence of up to 1.0M nitrite in the multianalyte standards had no significant effect for benzoylecgonine, morphine, and phencyclidine assays. With a high concentration of nitrite, ONLINE became more sensitive for amphetamine (detected more drug than what was expected) and less sensitive for THCCOOH (detected less drug than what was expected). No effects of nitrite were observed on the results of the Abuscreen ONTRAK assays. Similarly, no effects were observed on the absolute qualitative results of the TESTCUP-5 when testing the nitrite-adulterated standards. However, the produced intensities of the signals that indicate the negative test results were slightly lowered in the THC and phencyclidine assays. The presence of 1.0M of nitrite did not show dramatic interference with the GC-MS analysis of benzoylecgonine, morphine, amphetamine, and phencyclidine. In contrast, nitrite ion significantly interfered with the detection of THCCOOH by GC-MS. The presence of 0.03M of nitrite ion resulted in significant loss in the recovery of THCCOOH and its internal standard by GC-MS. The problem of nitrite adulteration could be alleviated by sodium bisulfite treatment even when the specimens were spiked with 1.0M of nitrite ion. Although bisulfite treatment decomposed all nitrite ions in the sample to recover the remaining THCCOOH by GC-MS, the net recovery of THCCOOH depended on urinary pH and time and conditions of sample storage. The presence of nitrite concentrations that might arise from all possible natural sources, including microorganisms, pathological conditions, and medications, did not interfere with the GC-MS analysis of THCCOOH.

Drugs detected in patients suspected of acute intoxication

Drug screens were performed for 434 adult patients who presented to the Parkland Memorial Hospital Emergency Department with suspected acute drug overdose. The screening consisted of analysis of urine by automated high performance liquid chromatography (REMEDi) in combination with qualitative EMIT immunoassays. Selected patients also had ethanol measured in blood, salicylate and acetaminophen measured in serum, and urine specimens analyzed qualitatively for cannabinoids. Most patients (83.4%), regardless of age, race, or gender, had evidence of consumption of at least one drug. The drugs detected most often were ethanol (30.0%) and cocaine (23.7%). At least one of the nine most common drugs-of-abuse (amphetamines, barbiturates, benzodiazepines, cannabinoids, cocaine, ethanol, opiates, opioids, and phencyclidine) was detected in 64.5% of the specimens, and combinations of these drugs were present in 45.4%. For most drugs, age, gender, ethnicity, time of day, day of week, and indication for screening could not be used to predict the drug screen result.

Certification of phencyclidine in lyophilized human urine reference materials

The National Institute of Standards and Technology (formerly the National Bureau of Standards), in cooperation with the College of American Pathologists (CAP), has certified the concentrations of phencyclidine (PCP) in two new reference materials (RMs). One of these materials is Standard Reference Material (SRM) 1511, Multidrugs of Abuse in Freeze-dried Urine, and the other material is a CAP PCP RM. In order to minimize the possibility of undetected bias, two independent analytical methods, employing gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, were used to certify PCP in these materials. Results from the two methods were in good agreement and were statistically combined to yield certified values of 23.8 ng/mL for PCP in SRM 1511 and 11.9, 23.4, and 49.5 ng/mL for three levels of PCP in the CAP RM. A round-robin study of SRM 1511 among five military laboratories demonstrated the suitability of the SRM for its intended purpose.

Cloned enzyme donor immunoassay (CEDIA) for drugs-of-abuse screening

Large numbers of specimens (5000-18,000) were screened for amphetamines, barbiturates, cocaine, marijuana, opiates, and phencyclidine by RIA (Roche), Emit II (Syva), and a new immunoassay, CEDIA (cloned enzyme donor immunoassay, Microgenics). All immunoassays performed equivalently for cocaine, opiates, and phencyclidine. All immunoassays detected the same amphetamine/methamphetamine-positive specimens, but all also detected numerous specimens containing cross-reacting sympathomimetic amines. CEDIA detected 100%, Emit II 93%, and RIA 82% of the barbiturate-positive specimens. Emit II and CEDIA detected 86-88% of the specimens found by RIA to be marijuana positive. A subset of specimens was additionally screened by OnLine (Roche) and TDx (Abbott) for amphetamines, cocaine, and marijuana. OnLine and TDx also detected all of the amphetamine-positive specimens and numerous specimens containing cross-reacting sympathomimetic amines. All immunoassays performed equivalently for cocaine, and the four nonisotopic tests detected 86-89% of the marijuana positives found by RIA. Interfering sympathomimetic amine drug compounds can be eliminated by using an oxidizing agent, thus decreasing the number of unconfirmable amphetamine presumptive positives. The CEDIAs for all of the major drugs of abuse are reliable and effective for large-volume urine screening programs.

Feasibility studies for simultaneous immunochemical multianalyte drug assay by capillary electrophoresis with laser-induced fluorescence

We present a method for the simultaneous quantification of multiple drug analytes in urine, based on combining immunochemical binding with capillary electrophoretic separation. Two fluorescent drug-cyanine (Cy) dye conjugates were prepared as competing species for the immunoassay. Morphine was derivatized with Cy5 (lambda max = 652 nm, epsilon = 215,000 mol-1cm-1 L), phencyclidine (PCP) with Cy5.5 (lambda max = 675 nm, epsilon = 200,000 mol-1cm-1L). The high-efficiency resolving power of the capillary electrophoresis system (20 microns x 27 cm column) separated the individual labeled drugs, and the antigen-antibody complexes were detected by laser-induced fluorescence (laser: 10 mW He-Ne at 632.8 nm) with Cy5 diacid as internal standard. Simultaneous competitive immunoassay of morphine and PCP in urine showed that the free labeled-drug peak areas were proportional to the concentrations of the drug species present in the urine sample. This immunoassay can be performed routinely and reproducibly in < 5 min with analytical detection limits of 4 nmol/L for PCP and 40 nmol/L for morphine.

Detection of phencyclidine in urine using a polarization fluoroimmunoassay

A polarization fluoroimmunoassay was developed for the detection of phencyclidine in urine and the reagents were adapted for use on the Abbott TDx analyser. The assay was used to look for evidence of phencyclidine abuse, over a 6 month period, amongst patients attending drug abuse clinics in the East End of London. Although over 2000 patients' samples tested negative, the assay successfully detected phencyclidine in an external quality control scheme.

Confirmatory tests for drugs in the workplace by gas chromatography-mass spectrometry

The Mandatory Guidelines for Federal Workplace Drug Testing Programs require the use of gas chromatography-mass spectrometry (GC-MS) for the confirmation of presumptive positive urine specimens. This review focuses upon GC-MS methods developed specifically for forensic confirmation of amphetamine, methamphetamine, 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-acid), benzoylecgonine, morphine, codeine and phencyclidine in urine for purposes of workplace drug testing. In addition, current laboratory issues pertaining to each drug class are reviewed. Generally, drug assays utilized either liquid-liquid or solid-phase extraction methods, derivatization if necessary, and GC-MS detection operating in the selected ion monitoring mode or by full scan acquisition.

Evaluation of Emit II reagents on the Chem 1

An evaluation study of Syva Emit II reagents using the Chem 1 was performed for the following drugs: barbiturates, benzodiazepines, cannabinoids, benzoylecgonine, opiates, and phencyclidine. The Emit II reagents (100-mL bottles) were reconstituted to 70 mL and evaluated against the Emit d.a.u. reagents. A minimum of 446 samples were run for each drug. For all drugs tested, there were a total of 11 discordant results between the two reagents. The Emit II reagent was found to be correct on 8 of the 11 discordances after retesting by FPIA or GC/MS. The CV of within-run and day-to-day precision of the Emit II was 1.8% or less and 12.3% or less, respectively.

Frequency of cocaine and phencyclidine detection at a large urban public teaching hospital

To assess the value of the current NIDA cutoff concentrations for screening assays that detect urinary cocaine metabolites and phencyclidine (PCP), we collected data on concentrations of these drugs in newborns and patients admitted to the Los Angeles County + University of Southern California Medical Center from July 1, 1991, to December 31, 1991. Less than 2% of the patients were positive for PCP. However, 16.5% of the newborns and 25.1% of the remaining age groups tested positive for cocaine metabolites. Among specimens that tested negative with the screening assays, approximately 3% (182 specimens, with 15 from newborns) clearly contained detectable amounts (between 50 and less than 300 ng/mL) of benzoylecgonine by GC/MS, while less than 0.6% had detectable amounts (10-25 ng/mL) of PCP. The mothers of 7 of the 15 newborns also had detectable benzoylecgonine at various concentrations. This indicates that a lower screening cutoff concentration may be desirable for cocaine metabolites in hospitalized patients. Among those patients positive for cocaine metabolites or PCP, most were males between 20 and 39 years old. The urine drug concentrations in this population were 4-300 times greater than the cutoff concentrations for the screening assays.

The role of oxidative metabolism in hexachlorobenzene-induced porphyria and thyroid hormone homeostasis: a comparison with pentachlorobenzene in a 13-week feeding study

Hexachlorobenzene (HCB) induces a broad spectrum of effects including disturbances in the heme synthesis (porphyria) and in thyroid hormone homeostasis. For most of its effects, biotransformation of the parent compound seems to be a prerequisite. The present study was designed to assess the relevance of the oxidative metabolites in HCB-induced toxicity, with special attention to the role of the reactive tetrachlorobenzoquinone (TCBQ). To this end, toxicity and biotransformation of HCB were compared with those of pentachlorobenzene (PCB), since this chemical is oxidized to the same products as HCB, i.e., pentachlorophenol (PCP) and TCBQ. Female Wistar rats received diets containing different dose levels of HCB or PCB for 13 weeks, with or without cotreatment with triacetyloleandomycin (TAO), a selective inhibitor of cytochrome P450IIIA1/2. Rats treated with HCB (high dose) had significantly elevated levels of urinary porphyrins from the 4th week on and had a significant hepatic accumulation of porphyrins at the end of the study. Both urinary porphyrin excretion and hepatic porphyrin accumulation were greatly inhibited in rats receiving cotreatment with HCB and TAO. However, the inhibition of HCB-induced porphyria by TAO cannot be explained by a diminished formation of the highly reactive TCBQ, since rats treated with a high dose of PCB, which had a several fold higher urinary excretion of PCP and TCHQ compared to a high dose of HCB, did not develop porphyria. Instead, the present study points to the involvement of a putative reactive intermediate in the primary oxidative step in HCB-induced porphyria, since based on paired observations of individual rats, the degree of porphyria was correlated to a high degree with excretion of PCP, whereas correlation of porphyria with early excretion of TCHQ was much weaker. This finding fits well with the fact that the mechanisms of oxidation of HCB to PCP and PCB to PCP are different. Both HCB and PCB were oxidized to PCP and tetrachlorohydroquinone (TCHQ), the reduced analog of TCBQ. Cytochrome P450IIIA1/2 appears to be involved in the conversion of HCB and PCB, since cotreatment of TAO resulted in a strongly diminished urinary excretion of PCP and TCHQ. Treatment with HCB as well as PCB results in disturbances of retinoid and thyroid hormone homeostasis. These effects, which have also been reported after exposure to polychlorinated biphenyls, originate from interference of hydroxylated metabolites (notably PCP) with the plasma thyroxine transport protein, transthyretine, and since this metabolite is formed from both HCB and PCB, this results in the same toxicity for both compounds.

Evaluation of the Syva ETS Plus urine drug and serum ethanol analyzer

The Syva ETS is an automated system designed for analysis of drugs of abuse in urine. Recently, the Syva Company has upgraded this system to the ETS Plus, which is capable of analyzing ethanol in urine, serum, or plasma. We evaluated the new ETS Plus for urine screening of barbiturates, benzodiazepines, cocaine metabolite, opiates, and phencyclidine. Results of 505 patient sample assays obtained by ETS Plus were compared with those of ETS. There were only four discrepant results which had absorbance rates close to the low calibrator cutoff values. The within-run precision of the ETS Plus Ethyl Alcohol Assay yielded a CV of 2.6% at a target value of 1.00 g/L (1.06 +/- 0.03 g/L, n = 32) and a CV of 3.2% at a target value of 0.40 g/L (0.42 +/- 0.01 g/L, n = 30). The linear regression analysis of 30 patient serum ethanol results by the ETS Plus and by gas chromatography yielded y = 0.939 x + 0.03 g/L. The software modifications in the new ETS Plus allow the accurate quantitation of ethanol in serum and reliable detection of drugs of abuse within the same batch.

The effects of adulterating agents on FPIA analysis of urine for drugs of abuse

A variety of chemical agents were evaluated to determine their effects on fluorescence polarization immunoassays for drugs of abuse. Sixteen different agents, at concentrations up to 10%, were tested against urine assays for cannabinoids, cocaine (metabolite), amphetamines, opiates, phencyclidine (PCP), and barbiturates. The potential to cause both false positive and false negative results was evaluated, and assays were performed one and seven days after sample adulteration to simulate different collection/testing formats. All six drug assays were susceptible to one or more adulterating agents, but the degree varied considerably between assays. The cannabinoid assay was most susceptible to adulterant-induced false negative results, and the barbiturate assay was most susceptible to false positive results. The remaining assays demonstrated relatively few, but characteristic effects, some of which were attributable to drug degradation and others to assay interference. Although the results of pH measurement on adulterated samples verified its utility in identifying some samples adulterated with interfering agents, other adulterants that cause substantial effects would not be identified by pH measurements alone.

Evaluation of enzyme immunoassay performance characteristics--phencyclidine example

Four reagent formulations (three provided by a manufacturer; one prepared in-house by mixing equal volumes of two commercial reagents) are used for the assay of phencyclidine (PCP) in urine samples. Performance characteristics evaluated included assay precision and sensitivity at and near the assay cutoff concentration. Data resulting from the reagent prepared in-house are better than those using then commercially available formulations, and are comparable with those obtained using the recently available new commercial formulation.

Solid phase extraction of phencyclidine from urine followed by capillary gas chromatography/mass spectrometry

This communication describes a method for the solid phase extraction of phencyclidine (PCP) from urine, followed by GC/MS analysis. The method is linear over the range 5-1000 ng/mL and consistently produces cleaner chromatograms than can be obtained by liquid-liquid extraction. The limits of detection and quantitation are 0.47 and 1.38 ng/mL, respectively. Extraction efficiency, or recovery, was found to be 100.8 +/- 6.5%, and the between-run precision was 3.5% (25 ng/mL, n = 51). This solid phase method for extraction of PCP from urine has several advantages over liquid-liquid extraction for laboratories of any size.

Evaluation of phencyclidine by EMIT d.a.u. utilizing the ETS analyzer and a 25-ng/mL cutoff

This study evaluates the usefulness of the EMIT d.a.u. phencyclidine assay using the Syva ETS instrument to reliably detect phencyclidine in urine specimens at 25 ng/mL and above. More than 1600 urine specimens were screened over a one-month period. Fifty three (53) specimens screened positive (25 of these were previously tested positive by EMIT and GC/MS at or above the 25-ng/ml level and resubmitted as unknowns). Of the 53 specimens, 52 were confirmed positive by GC/MS. Reanalysis by EMIT of the one sample that was confirmed negative by GC/MS yielded a negative result. The absorbance difference between a negative sample and a sample containing 25 ng/mL of phencyclidine averaged 53 absorbance units with a standard deviation of 7.7 units. The absorbance difference between a negative sample and a sample containing 75 ng/mL of phencyclidine averaged 105 absorbance units with a standard deviation of 6.8 units.

Immunoassay method validation for a modified EMIT phencyclidine assay

Immunoassay drug testing methods, that have been modified from the manufacturers' recommended procedure to be used for the analysis of federally regulated specimens or other forensic samples require evaluation to ensure their scientific validity. These validation studies must demonstrate the accuracy, precision, and linearity of the modified immunoassay around the cutoff concentration, substantiate adequate rate separation, and verify the ability of the assay to differentiate positive and negative samples. Modification of the EMIT d.a.u. phencyclidine assay in order to achieve the federally mandated cutoff concentration of 25 ng/mL is common. This study describes the validation of a modified EMIT phencyclidine assay and a protocol that allows for the evaluation of similarly modified immunoassays.

Drug screening with EMIT reagents: a quantitative approach to quality control

We investigated the precision, linearity, accuracy, and stability of quantitative results for five drugs of abuse [amphetamines, benzoylecgonine, opiates, phencyclidine, and the cannabinoid-tetrahydrocannabinol (THC)-9-acid metabolite], analyzed in control specimens by using EMIT d.a.u. reagents (Syva Co.) with a Monarch 2000 analyzer with a nonlinear interpolation curve-fitting algorithm. The within-day and between-days coefficients of variation (CVs) were less than 5% for all drugs except THC-9-acid, which had a CV between 10% and 20%. The drift of control values during a 30-day stability study was less than 10% from target values for three weeks after a single calibration, except for THC-9-acid control values, which were stable for only two to three days. Daily calibration reduced the drift away from target values during the 30-day stability study and produced optimum precision of all drug assays. Mean control values near the National Institute on Drug Abuse cutoff limits were within 10% of their target values.

Detectability of phencyclidine and 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid in adulterated urine by radioimmunoassay and fluorescence polarization immunoassay

The ability to alter immunoassay test results by the addition of some commonly available chemicals to drug-positive and drug-negative urine specimens was investigated. Urine specimens containing either phencyclidine (PCP) or 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (9-THC-COOH) were adulterated with sodium chloride, bleach, vinegar, potassium hydroxide, liquid soap, 2-propanol, and ammonia. Subsequent analyses by radioimmunoassay (RIA) and fluorescence polarization immunoassay (FPIA) demonstrated false positive and false negative results with some adulterants. Radioimmunoassay false positives occurred with potassium hydroxide (PCP and THC-COOH assays) and bleach (THC-COOH assay) adulterants. Bleach (PCP assay) and soap (THC-COOH assay) additives resulted in false negative analyses by RIA. No adulterant caused FPIA false positives. FPIA false negatives occurred with bleach (PCP and THC-COOH assays) and potassium hydroxide (PCP assay) adulterants.

Abbott phencyclidine and barbiturates abused drug assays: evaluation and comparison of ADx FPIA, TDx FPIA, EMIT, and GC/MS methods

This study evaluated the capability of the Abbott ADx assays to test for phencyclidine (PCP) and barbiturates in urine specimens by comparison to TDx, EMIT, and gas chromatographic/mass spectrometric (GC/MS) methods. Within-run and between-run precision were determined using three control samples (35, 100, and 250 ng/mL PCP; 0.4, 0.6, and 1.0 mg/L secobarbital) tested over a two-week period. Controls were analyzed in both single assay (batch) and multiple assay (combination) modes. Within-run coefficients of variation (CVs) for the three PCP controls were 2.4, 2.6, and 2.2%, respectively; the between-run CVs were 4.0, 3.5, and 2.8%, respectively. The within-run CVs for the three barbiturate controls were 3.0, 2.7, and 2.7%, respectively; the between-run CVs were 5.6, 4.7, and 4.5%, respectively. Fifty specimens not containing PCP or barbiturates, 50 specimens containing PCP, and 50 specimens containing barbiturates were tested by ADx, TDx, EMIT, and GC/MS. The methods compared favorably and no false positive or false negative results were obtained by any immunoassay method for any assay when compared to GC/MS.

Screening of blood and urine for drugs of abuse utilizing diagnostic products corporation's Coat-A-Count radioimmunoassay kits

Solid-phase radioimmunoassay methods for the uniform analysis in hemolyzed whole blood and urine of opiates, methamphetamine, cocaine, free morphine, and phencyclidine using Coat-A-Count kits available from Diagnostic Products Corporation were tested for cost effectiveness without compromising the reliability of the results. Results indicate these kits are superior in performance in cross-reactivity studies, noted particularly in the methamphetamine assay, labor conservation, and cost-effectiveness to double-antibody radioimmunoassay methods.

Interference of common household chemicals in immunoassay methods for drugs of abuse

I report how some adulterants affect results for drugs of abuse in urine as measured by Roche RIA, Syva emit d.a.u., and Abbott TDx fpia (fluorescence polarization immunoassay) for the following drugs: amphetamines, barbiturates, benzodiazepines, cannabinoids, cocaine, opiates, and phencyclidine (PCP). Sodium chloride interfered negatively with all of these drugs when assayed by emit and caused a slight decrease in measured benzodiazepine concentration by fpia. Drug concentrations were also decreased by added H2O2 (emit: benzodiazepine), Joy detergent (emit: cannabinoid, benzodiazepines, PCP), NaHCO3 (emit: opiate; fpia: PCP), or NaClO [corrected] (emit, RIA, fpia: amphetamines, opiates, PCP; emit, fpia: cannabinoid; emit: benzodiazepines). False-positive results were caused by H2O2 (fpia: benzodiazepines) and Joy (RIA, fpia: benzodiazepine, cannabinoid; fpia: barbiturate, amphetamine). Sodium bicarbonate causes a suspiciously high pH in the urine, NaClO [corrected] an apparently low pH (using pH paper).

Evaluation of the Keystone Diagnostic Quik Test. A paper chromatography test for drugs of abuse in urine

The Keystone Diagnostic Inc (KDI) Quik Test is advertised to be an on-site, rapid, broad-spectrum paper chromatography test that is marketed for use in industry, drug abuse treatment facilities, and physician's offices. Even when unskilled individuals perform the test, five drugs of abuse, excluding marijuana, are said by the manufacturer to be reliably detected. In this study, ten confirmed drug-free urine specimens and 56 specimens positive by an immunoassay screening test, and confirmed by gas chromatography/mass spectrometry, for cocaine (n = 32), phencyclidine (n = 12), or opiate drugs (n = 12), were reanalyzed by the KDI Quik Test. The sensitivity of the KDI Quik Test was 62.5%, specificity was 70%, predictive value of a negative test was 36%, and efficiency was 64%. In too many instances the KDI Quik Test did not detect the drugs for which it is intended. Paper chromatography tests such as the KDI Quik Test are inaccurate and as such are unacceptable in any setting for the purposes of screening for drugs of abuse.