Urinary screening for alprazolam and its major metabolites by the Abbott ADx and TDx analyzers with confirmation by GC/MS

Alprazolam is a short-acting triazolobenzodiazepine with anxiolytic and antidepressant properties. It has a half-life of 10-15 hours after multiple oral doses. Approximately 20% of an oral dose is excreted unchanged in the urine. The major urinary metabolites are alpha-OH alprazolam glucuronide and 3-HMB benzophenone glucuronide. The objective of this study was to characterize the reactivity of alprazolam and three metabolites in the Abbott ADx and TDx urinary benzodiazepine assays compared with the EMIT d.a.u. benzodiazepine assay. Alprazolam (at 300 ng/mL) gave an equivalent response as the 300 ng/mL low control (nordiazepam). alpha-OH alprazolam gave an equivalent response to this control between 300-500 ng/mL and 4-OH alprazolam between 500-1000 ng/mL. The 3-HMB benzophenone was not positive even at 10,000 ng/mL. The ADx screening assay was positive in 26 of 31 urine specimens collected from alprazolam-treated patients. All 31 of these specimens were confirmed positive for alpha-OH alprazolam by GC/MS after enzymatic hydrolysis and formation of a TMS derivative. For the TDx, 27 of 31 specimens were positive for benzodiazepines and all 31 were confirmed by GC/MS. All 5 of the negative ADx specimens and 4 of 5 TDx specimens contained 150-400 ng/mL of alpha-OH alprazolam. In conclusion, both the ADx and TDx urine benzodiazepine assays are acceptable screening assays for alprazolam use when the alpha-OH alprazolam concentration is greater than 400 ng/mL.     

Cocaine and its major metabolites in plasma and urine samples from patients in an urban emergency medicine setting

In this retrospective study, we examined the levels of cocaine and its major metabolites in plasma and urine from 29 randomly selected emergency department patients (19 males and 10 females, aged 19 to 55) whose urine screened positive for benzoylecgonine using fluorescence polarization immunoassay. Levels of cocaine along with benzoylecgonine, ecgonine methyl ester, and norcocaine were quantitated in EDTA plasma and urine from each patient using gas chromatography-mass spectrometry with selected ion monitoring. Admission diagnosis and history were also obtained for each patient. In plasma, the levels were 16-130 ng/mL for cocaine (n = 3), 27-96 ng/mL for ecgonine methyl ester (n = 9), and 18-1390 ng/mL for benzoylecgonine (n = 22). Norcocaine was not detected in any of the plasma samples. In urine, the concentration ranges were 4-40,130 ng/mL for cocaine (n = 23), 36-660,500 ng/mL for ecgonine methyl ester (n = 27), and 9-2520 ng/mL for norcocaine (n = 9). All urine samples were positive for benzoylecgonine (106-3,361,000 ng/mL), and benzoylecgonine was the only metabolite present in two urine samples (at concentrations of 407 and 435 ng/mL). Two patients had plasma and urine samples positive for all analytes (except norcocaine in plasma). The patient with the highest urinary concentrations of cocaine (40,130 ng/mL), ecgonine methyl ester (660,500 ng/mL), benzoylecgonine (3,361,000 ng/mL), and norcocaine (2520 ng/mL) had a small quantity of benzoylecgonine (465 ng/mL) in plasma. No correlation was noted with patient history, admitting diagnosis or symptomatology, or plasma/urine levels of cocaine or any of its metabolites.     

Quantitation of cocaine and its major metabolites in human saliva using gas chromatography-positive chemical ionization-mass spectrometry (GC-PCI-MS)

An analytical method for the simultaneous determination of cocaine (COC) and its major metabolites, ecgonine methyl ester (EME) and benzoylecgonine (BEG), in saliva was developed. The method involves liquid-liquid extraction in Toxitubes A, derivatization with 99:1 (v/v) N,O-bis-trimethylsilyltrifluoroacetamide (BSTFA)/trimethylchlorosilane (TMCS) and gas chromatography-mass spectrometry (GC-MS) determination. The detector response thus obtained is linear over the range 25-1000 ng/mL, with a reproducibility better than 93% and a recovery close to 100% for the three analytes. The limits of detection achieved were 0.9 ng/mL for EME, 2.2 ng/mL for cocaine, and 0.2 ng/mL for BEG, and the limits of quantitation were 3.0 ng/mL for EME, 7.4 ng/mL for cocaine, and 0.8 ng/mL for BEG. The proposed method was applied to 48 saliva samples from cocaine users, 96% of which were positive for the drug and/or its metabolites. Saliva is thus a suitable biological fluid for determining cocaine, EME, and BEG by GC-PCI-MS.     

Major and minor metabolites of cocaine in human plasma following controlled subcutaneous cocaine administration

Cocaine is rapidly metabolized to major metabolites, benzoylecgonine (BE) and ecgonine methyl ester (EME), and minor metabolites, norcocaine, p-hydroxycocaine, m-hydroxycocaine, p-hydroxybenzoylecgonine (pOHBE), and m-hydroxybenzoylecgonine. This IRB-approved study examined cocaine and metabolite plasma concentrations in 18 healthy humans who provided written informed consent to receive low (75 mg/70 kg) and high (150 mg/70 kg) subcutaneous cocaine hydrochloride doses. Plasma specimens, collected prior to and up to 48 h after dosing, were analyzed by gas chromatography-mass spectrometry (2.5 ng/mL limits of quantification). Cocaine was detected within 5 min, with mean+/-SE peak concentrations of 300.4+/-24.6 ng/mL (low) and 639.1+/-56.8 ng/mL (high) 30-40 min after dosing. BE and EME generally were first detected in plasma 5-15 min post-dose; 2-4 h after dosing, BE and EME reached mean maximum concentrations of 321.3+/-18.4 (low) and 614.7+/-46.0 ng/mL (high) and 47.4+/-3.0 (low) and 124.4+/-18.2 ng/mL (high), respectively. Times of last detection were BE>EME>cocaine. Minor metabolites were detected much less frequently for up to 32 h, with peak concentrations相似文献   

GC-MS confirmation of codeine, morphine, 6-acetylmorphine, hydrocodone, hydromorphone, oxycodone, and oxymorphone in urine.

A procedure for the simultaneous confirmation of codeine, morphine, 6-acetylmorphine, hydrocodone, hydromorphone, oxycodone, and oxymorphone in urine specimens by gas chromatography-mass spectrometry (GC-MS) is described. After the addition of nalorphine and naltrexone as the two internal standards, the urine is hydrolyzed overnight with beta-glucuronidase from E. coli. The urine is adjusted to pH 9 and extracted with 8% trifluoroethanol in methylene dichloride. After evaporating the organic, the residue is sequentially derivatized with 2% methoxyamine in pyridine, then with propionic anhydride. The ketone groups on hydrocodone, hydromorphone, oxycodone, oxymorphone, and naltrexone are converted to their respective methoximes. Available hydroxyl groups on the O3 and O6 positions are converted to propionic esters. After a brief purification step, the extracts are analyzed by GC-MS using full scan electron impact ionization. Nalorphine is used as the internal standard for codeine, morphine, and 6-acetylmorphine; naltrexone is used as the internal standard for the 6-keto-opioids. The method is linear to 2000 ng/mL for the 6-keto-opioids and to 5000 ng/mL for the others. The limit of quantitation is 25 ng/mL in hydrolyzed urine. Day-to-day precision at 300 and 1500 ng/mL ranged between 6 and 10.9%. The coefficients of variation for 6-acetylmorphine were 12% at both 30 and 150 ng/mL. A list of 38 other basic drugs or metabolites detected by this method is tabulated.     

Rapid confirmation/quantitation of ecgonine methyl ester, benzoylecgonine, and cocaine in urine using on-line extraction coupled with fast HPLC and tandem mass spectrometry

A rapid, rugged, and highly specific assay for the quantitation of cocaine (COC) and especially its primary metabolites benzoylecgonine (BZE) and ecgonine methyl ester (EME) in human urine has been established. Here, we investigated the use of on-line sample extraction coupled to rapid chromatography systems for tandem mass analysis of COC, EME, and BZE in human urine. Using this method, sample preparation consisted of a sole centrifugation step. Combined extraction and chromatographic run times were < 3.5 min. The lower limits of detection were 0.5 ng/mL, 2.0 ng/mL, and 0.5 ng/mL for EME, BZE, and COC, respectively. Linear calibration curves ranging from 7.5 ng/mL to 1000 ng/mL were produced for the test analytes. Within-day and between-day precision and accuracy of the assay were determined using human urine quality-control specimens at 5, 10, or 15; 150; and 1000 ng/mL. The analyses were performed over the course of five days, rendering %CVs < 10% for EME, BZE, and COC. Percent mean accuracy for the three analytes of 97 to 113% were obtained. Our data suggest that on-line sample extraction coupled with rapid high-performance liquid chromatography-tandem mass spectrometry may be a viable alternative for EME, BZE, and COC analyses in human urine.     

A rapid HPLC procedure for the simultaneous determination of chloroquine, monodesethylchloroquine, diazepam, and nordiazepam in blood

Chloroquine, monodesethylchloroquine, diazepam, and nordiazepam levels are simultaneously determined in whole blood or plasma by HPLC. Papaverine is used as internal standard, and the analysis is performed after protein-binding hydrolysis, absorption on Extrelut, and elution with diethyl ether/methylene chloride (70:30 v/v). UV detection is used at 343 nm for 12 min, then changed to 242 nm. There are two mobile phases with two flow rates. The procedure requires 30 min, is reproducible, sensitive (8-10 ng/mL for chloroquine and its metabolite, 4 ng/mL for diazepam and nordiazepam), and selective, especially towards other antimalarial agents and drugs like adrenaline or barbiturates, which may be used in chloroquine poisoning therapy. It can be used for pharmacokinetic studies, therapeutic control, to establish the diagnosis and prognosis of a chloroquine poisoning, and to follow and optimize treatment.     

High-pressure liquid chromatographic determination of ranitidine, a new H2-receptor antagonist, in plasma and urine

An assay is described for the determination of a new H2-receptor antagonist, ranitidine, and its desmethyl metabolite in human plasma and urine. Alkalinized plasma or urine was extracted with methylene chloride, the organic phase was evaporated, and the reconstituted residue was analyzed by high-pressure liquid chromatography using a reversed-phase column. Two other identified metabolites of ranitidine, the S-oxide and N-oxide, were separated chromtographically from both ranitidine and the desmethyl metabolite. However, these metabolites could not be quantitative due to poor analytical recovery and interference from endogenous components. The sensitivity limits were 5 ng/ml for ranitidine and 15 ng/ml for desmethylranitidine. Plasma samples from two volunteers who were given oral ranitidine (0.1, 0.2, and 0.4 mg/kg) at 1-week intervals were assayed. Peak levels of 30--130 ng/ml were achieved between 40 and 120 min after dosage, followed by an elimination half-life of 2.9-3.9 hr. Plasma levels of ranitidine were still detectable at 8 hr but were below the sensitivity of the assay by 24 hr. Plasma levels of the desmethyl metabolite were seldom above the threshold sensitivity of the assay. Urinary excretion of unmetabolized ranitidine accounted for 77% of the administered dose, whereas only 4% appeared as desmethylranitidine.     

The determination of the triazolobenzodiazepine triazolam in post mortem samples

A post mortem case involving the triazolobenzodiazepine triazolam is reported. Levels of 38 ng/g in the liver and 6.7 ng/mL in the blood were determined by reversed-phase high-performance liquid chromatography (HPLC) using an eluent of 0.06% acetic acid:acetonitrile (61:39) and ultraviolet detection at 221 nm. The presence of triazolam in the post mortem samples was verified by its oxidation to a benzophenone with potassium dichromate, followed by the analysis of the oxidized extract by HPLC using a silica column and an eluent of dichloromethane:methanol (97.5:2.5) at 250 nm.     

Evaluation of the antibacterial activity of the methylene chloride extract of Miconia ligustroides,isolated triterpene acids,and ursolic acid derivatives

The methylene chloride extract of Miconia ligustroides (DC.) Naudin (Melastomataceae), the isolated compounds ursolic and oleanolic acids and a mixture of these acids, and ursolic acid derivatives were evaluated against the following microorganisms: Bacillus cereus (ATCC 14579), Vibrio cholerae (ATCC 9458), Salmonella choleraesuis (ATCC 10708), Klebsiella pneumoniae (ATCC 10031), and Streptococcus pneumoniae (ATCC 6305). The microdilution method was used for determination of the minimum inhibitory concentration (MIC) during evaluation of the antibacterial activity. The methylene chloride extract showed no activity against the selected microorganisms. Ursolic acid was active against B. cereus, showing a MIC value of 20?μg/mL. Oleanolic acid was effective against B. cereus and S. pneumoniae with a MIC of 80?μg/mL in both cases. The mixture of triterpenes, ursolic and oleanolic acids, did not enhance the antimicrobial activity. However, the acetyl and methyl ester derivatives, prepared from ursolic acid, increased the inhibitory activity for S. pneumoniae.     

Patterns of free (unconjugated) buprenorphine, norbuprenorphine, and their glucuronides in urine using liquid chromatography-tandem mass spectrometry

Patterns of buprenorphine and metabolites were examined in 1946 positive urine samples analyzed by liquid chromatography-tandem mass spectrometry for free (unconjugated) buprenorphine and norbuprenorphine (quantitative, 2 to 1000 ng/mL) and buprenorphine-glucuronide (B3G) and norbuprenorphine-glucuronide (N3G) (semi-quantitative, 5 to 1000 ng/mL). Two distribution patterns predominated with 49.1% positive for norbuprenorphine, B3G, and N3G and 41.6% positive for buprenorphine, norbuprenorphine, B3G, and N3G. Buprenorphine, positive in 45.5% of samples, was mostly < 5 ng/mL (median 6.1 ng/mL), but 9.8% were > 1000 ng/mL. Norbuprenorphine, B3G, and N3G had semi-Gaussian distributions with medians of 64.7, 108, and 432 ng/mL, respectively. With buprenorphine < 100 ng/mL (767 samples) or ≥ 100 ng/mL (19 quantifiable samples), the respective median metabolic ratios (free norbuprenorphine/free buprenorphine) were 25.0 and 0.15. In 12 retested "> 1000 ng/mL" buprenorphine samples, free buprenorphine was 4160 to 39,400 ng/mL and free naloxone 2140 to 9560 ng/mL. In 87 subsequent samples with buprenorphine < 20 ng/mL, naloxone concentrations were < 50 ng/mL. Concentrations of buprenorphine > 100 ng/mL (particularly with low metabolite concentrations) are suspect of urine adulteration with medication (4% in the database) that can be checked in most cases by concurrent analysis for naloxone.     

Simultaneous and sensitive analysis of THC, 11-OH-THC, THC-COOH, CBD, and CBN by GC-MS in plasma after oral application of small doses of THC and cannabis extract

Besides the psychoactive Delta(9)-tetrahydrocannabinol (THC), hashish and marijuana as well as cannabis-based medicine extracts contain varying amounts of cannabidiol (CBD) and of the degradation product cannabinol (CBN). The additional determination of these compounds is interesting from forensic and medical points of view because it can be used for further proof of cannabis exposure and because CBD is known to modify the effects of THC. Therefore, a method for the simultaneous quantitative determination of THC, its metabolites 11-hydroxy-Delta(9)-tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy-Delta(9)-tetrahydrocannabinol (THC-COOH), CBD and CBN from plasma was developed. The method was based on automatic solid-phase extraction with C(18) ec columns, derivatization with N,O-bistrimethylsilyltrifluoroacetamide (BSTFA), and gas chromatography-electron impact ionization-mass spectrometry (GC-EI-MS) with deuterated standards. The limits of detection were between 0.15 and 0.29 ng/mL for THC, 11-OH-THC, THC-COOH, and CBD and 1.1 ng/mL for CBN. The method was applied in a prospective pharmacokinetic study after single oral administration of 10 mg THC alone or together with 5.4 mg CBD in cannabis extract. The maximum plasma concentrations after cannabis extract administration ranged between 1.2 and 10.3 ng/mL (mean 4.05 ng/mL) for THC, 1.8 and 12.3 ng/mL (mean 4.9 ng/mL) for 11-OH-THC, 19 and 71 ng/mL (mean 35 ng/mL) for THC-COOH, and 0.2 and 2.6 ng/mL (mean 0.95 ng/mg) for CBD. The peak concentrations (mean values) of THC, 11-OH-THC, THC-COOH, and CBD were observed at 56, 82, 115, and 60 min, respectively, after intake. CBN was not detected. Caused by the strong first-pass metabolism, the concentrations of the metabolites were increased during the first hours after drug administration when compared to literature data for smoking. Therefore, the concentration ratio 11-OH-THC/THC was discussed as a criterion for distinguishing oral from inhalative cannabis consumption.     

毛细管气相色谱法测定溴甲基纳曲酮中有机溶剂残留量

目的建立以毛细管气相色谱法测定溴甲基纳曲酮中二氯甲烷、丙酮、甲醇、甲基叔丁基醚、乙酸乙酯和甲苯6种有机溶剂残留量的方法。方法采用DB-WAX(30.0 m×0.25 mm,0.25μm)毛细管柱,氢火焰离子化检测器(FID),载气为氮气,柱流量为1.0 mL.min 1,进样口温度为240℃,检测器温度为250℃,柱温为程序升温。结果甲基叔丁基醚、丙酮、乙酸乙酯、甲醇、二氯甲烷和甲苯6种有机溶剂均得到有效分离,回收率及线性关系皆良好,且3批样品中有机溶剂残留量均符合规定。结论该方法操作简便,精密度好,准确可靠,可用于溴甲基纳曲酮中有机溶剂残留量的测定。     

A simple and rapid liquid chromatographic method for the determination of major metabolites of sulfasalazine in biological fluids

A simple and rapid assay for quantitation of sulfasalazine metabolites in rat urine and plasma was developed using high-performance liquid chromatography (HPLC). The method involves dilution of urine or plasma samples (0.1 mL) with methanol for protein precipitation, followed by mixing and centrifugation at 10,000 x g. Chromatography was accomplished with a reversed-phase ODS C-18 column (5 mu; 4.6 x 250 mm). The mobile phase consisted of 20% methanol in 5.0 mM phosphate buffer (pH 6.0), with 0.5 mM tetrabutylammonium chloride as an ion-pairing agent. The flow rate was 1.7 mL/min. An injection volume of 30 microL was used and the metabolites were quantitated by an ultraviolet detector at 254 nm. Benzamide was used as the internal standard. This method is linear in the range of 0.5 to 25 micrograms/mL for 5-aminosalicylic acid (5-ASA), acetylsulfapyridine (Ac-SP), and acetyl-5-aminosalicylic acid (Ac-5-ASA), and from 0.25 to 25 micrograms/mL for sulfapyridine (SP). The percent relative standard deviation ranged from 1 to 7.9% for the metabolite standard curves and precision studies. The limit of detection for 5-ASA, Ac-SP, and Ac-5-ASA is 100 ng/mL, and for SP is 50 ng/mL, in both urine and plasma. This method is rapid, precise, and accurate, and has been used to determine sulfasalazine metabolites in individual rat plasma and urine samples following an oral dose of 60 mg/kg of sulfasalazine.     

Detection of cocaine and its metabolites in whole blood and plasma following a single dose,controlled administration of intranasal cocaine

The disposition of drugs and their metabolites have been extensively described in the literature, based primarily on the analysis of plasma and urine. However, there are more limited data on their disposition in whole blood, which is often the only specimen available in forensic investigations and cases of driving under the influence of drugs. In this study, we have, for the first time, established pharmacokinetic properties of cocaine (COC) and its metabolites from concurrently collected whole blood and plasma samples, following a single 100 mg dose of cocaine hydrochloride administered via nasal insufflation to seven healthy volunteers. The median C_max of COC and its major metabolites, benzoylecgonine (BZE) and ecgonine methyl ester (EME), were closely related in whole blood and plasma. The median C_max for COC in plasma was 379.7 ng/mL (347.5–517.7) and 344.24 ng/mL (271.6–583.2) in whole blood. The median C_max for BZE in plasma was 441.2 ng/mL (393.6–475. and 371.18 ng/mL (371.1–477.3) in whole blood, EME was 105.5 ng/mL (93.6–151.8) in plasma and 135.5 ng/mL (87.8–183) in whole blood. Calculated medians of the whole blood to plasma ratio of COC (0.76), BZE (0.98) and EME (1.02) of approximately 1, strongly suggesting that the erythrocyte cell wall presents no barrier to COC and its metabolites. Furthermore, whole blood and plasma concentrations of COC were strongly correlated (R² = 0.0914 R = 0.956, p < 0.0001), as was BZE (R² = 0.0932 R = 0.965, p < 0.0001) and EME (R² = 0.0964R = 0.928, p < 0.0001). The minor oxidative metabolite norcocaine (NCOC) was detected in both whole blood and plasma at concentrations between 1 and 5 ng/mL within 60–180 minutes, suggesting that NCOC could be indicator of recent COC administration. Data from this study have shown for the first time that COC and its metabolites BZE and EME are evenly distributed between plasma and whole blood following controlled single‐dose intranasal COC administration.     

Urinary screening for alpha-OH triazolam by FPIA and EIA with confirmation by GC/MS.

Triazolam is a very short-acting triazolobenzodiazepine with sedative-hypnotic properties. Approximately 2% of an oral dose is excreted unchanged in the urine. The major urinary metabolite is alpha-hydroxytriazolam glucuronide (70% of the dose). The objective of this study was to characterize the reactivity of alpha-hydroxytriazolam in the urine benzodiazepine assay by fluorescence polarization immunoassay (FPIA; Abbott TDx) in comparison with enzyme immunoassay (EIA; Syva EMIT d.a.u. benzodiazepine assay). alpha-OH triazolam at 300 ng/mL gave a response equivalent to the 200-ng/mL nordiazepam Abbott calibrator. In the EMIT assay, alpha-OH triazolam gave a response equivalent to the 300-ng/mL calibrator (Syva) at 100-200 ng/mL. Both immunoassays gave positive results in 9 out of 9 urine specimens collected from individuals receiving triazolam. Confirmation was performed by analyzing for alpha-OH triazolam after enzymatic hydrolysis and formation of a TMS derivative for GC/MS. All urine specimens were positive for alpha-OH triazolam. In conclusion, both the FPIA and EIA immunoassay screening assays are acceptable for detecting the presence of alpha-OH triazolam in the urine of patients receiving therapeutic doses of triazolam.     

Quantitative liquid chromatographic determination of bromadoline and its N-demethylated metabolites in blood, plasma, serum, and urine samples

Bromadoline and its two N-demethylated metabolites were extracted into ether:butyl chloride after the addition of internal standard and basification of the various biological fluids (blood, plasma, serum, and urine). These compounds were then extracted into dilute phosphoric acid from the organic phase and separated on a reversed-phase chromatographic system using a mobile phase containing acetonitrile and a buffer of 1,4-dimethylpiperazine and perchloric acid. The overall absolute extraction recoveries of these compounds were approximately 50-80%. The background interferences from the biological fluids were negligible and allowed quantitative determination of bromadoline and the metabolites at levels as low as 2-5 ng/mL. At mobile phase flow rate of 1 mL/min, the sample components and the internal standard were eluted at the retention times within approximately 7-12 min. The drug- and metabolite-to-internal standard peak height ratios showed excellent linear relationships with their corresponding concentrations. The analytical method showed satisfactory within- and between-run assay precision and accuracy, and has been utilized in the simultaneous determination of bromadoline and its two N-demethylated metabolites in biological fluids collected from humans and from dogs after administration of bromadoline maleate.     

Dermal absorption of camphor, menthol, and methyl salicylate in humans

Camphor, menthol, and methyl salicylate occur in numerous over-the-counter products. Although extensively used, there have been no estimates of human exposure following administration via dermal application. Furthermore, there is little information about the pharmacokinetics of those compounds. The authors report the plasma concentrations of the intact compounds as a function of dose following dermal patch application. Three groups of 8 subjects (4 male, 4 female) applied a different number of commercial patches (2, 4, or 8) to the skin for 8 hours. Plasma samples were assayed using sensitive and selective gas-chromatographic methods. For the 8-patch group, the average maximum plasma concentrations (Cmax +/- SD) were 41.0 +/- 5.8 ng/mL, 31.9 +/- 8.8 ng/mL, and 29.5 +/- 10.5 ng/mL for camphor, menthol, and methyl salicylate, respectively. The corresponding values for the 4-patch group were 26.8 +/- 7.2 ng/mL, 19.0 +/- 5.4 ng/mL, and 16.8 +/- 6.8 ng/mL. The harmonic mean terminal half-lives were 5.6 +/- 1.3 hours, 4.7 +/- 1.6 hours, and 3.0 +/- 1.2 hours for camphor, menthol, and methyl salicylate, respectively. The 2-patch group had measurable but low plasma concentrations of each compound. Low-dose dermal application for an extended time results in low plasma concentrations of all 3 compounds. Four and 8 patches, when applied for 8 hours, gave measurable and nearly proportional plasma concentrations. Although unable to determine the absolute dermal bioavailability of these compounds, there appears to be relatively low systemic exposure to these potentially toxic compounds, even when an unrealistically large number of patches are applied for an unusually long time.     

A rapid reusable fiber optic biosensor for detecting cocaine metabolites in urine.

Analyte 2000, a four-channel fiber optic biosensor (FOB), was used for analysis of cocaine and its metabolites (COC) in human urine using a competitive fluorescence immunoassay. Binding of antibenzoylecgonine monoclonal antibody (mAb) to the casein-benzoylecgonine Ag-coated, tapered optical fibers was inhibited by COC. Bound mAb, which inversely correlated with COC concentration, was quantitated by fluorescence produced by evanescent excitation of bound cyanine dye-tagged antimouse antibody (CY5-Ab). The effective concentration range of benzoylecgonine (BE) for inhibiting the fluorescent signals was 0.75-50 ng/mL, with IC50 of 9.0 ng/mL. This FOB had similar affinities for BE, cocaine, and cocaethylene, but very low affinities for ecgonine and ecgonine methyl ester. A sensitivity of 100% and a specificity of 96% were achieved when 54 human urine specimens were analyzed by FOB (cutoff, 300 ng/mL COC) and GC-MS (cutoff, 150 ng/mL BE). All results were in agreement except for one positive FOB result with a GC-MS BE concentration of 148 ng/mL. In addition, regeneration and reuse of the fiber for multiple analyses were performed successfully with no carryover from specimens containing high COC concentrations to specimens containing low COC concentrations.     

Rapid quantification of urinary 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid using fast gas chromatography-mass spectrometry

Human urine specimens that were determined to be presumptively positive for metabolites of delta9-tetrahydrocannabinol by immunoassay screening were assayed using a novel fast gas chromatography-mass spectrometry (FGC-MS) analytical method to determine whether this method would improve the efficiency of specimen processing without diminishing the reliability of metabolite identification and quantification. Urine specimens were spiked with deuterated internal standard, subjected to solid-phase extraction, and derivatized using tetramethylammonium hydroxide and iodomethane. The methyl ester/methyl ether derivatives were identified and quantified using both a traditional GC-MS method and the newly developed FGC-MS method. The FGC-MS method was demonstrated to be linear between 3.8 and 1500 ng/mL 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (11-nor-delta-THC-COOH). The intrarun precision of 15 replicates of a 15 ng/mL control and the interrun precision of 161 sets of 7, 15, and 60 ng/mL controls were acceptable (coefficients of variation < 5.5%). The FGC-MS method was demonstrated to be specific for identifying 11-nor-delta9-THC-COOH and none of 43 tested substances interfered with identification and quantification of 11-nor-delta9-THC-COOH. Excellent data concordance (R2 > 0.993) was found for two specimen sets assayed using both methods. The FGC-MS method, when compared with a traditional GC-MS method, reduces total assay time by approximately 40% with no decrease in data quality.