Clinical pharmacokinetics and drug exposure-toxicity correlation study of docetaxel based chemotherapy in Chinese head and neck cancer patients.

BACKGROUND: Area under time-concentration curve (AUC) of docetaxel is related with its toxicity and efficacy. The aim of this study is to investigate the target range of docetaxel AUC in Chinese head and neck cancer (HNC) patients. METHODS: Eligible HNC patients were enrolled and received at least 2 cycles of docetaxel-based chemotherapy. A simplified pharmacokinetic (PK) strategy (2 monitored samples) was developed to simulate docetaxel AUC using the nonlinear mixed-effect modelling program. Preliminary target range of AUC was pre-set as 2.5-3.7 µg·hr/mL according to pooled analysis from 8 previous studies. Fisher exact test was used to analyze the relationship between AUC with neutropenia and efficacy, and to verify the target range. RESULTS: Thirty-nine eligible patients were enrolled. Grade 3-4 and grade 4 neutropenia rate in 1st cycle was 64% and 36%, respectively. AUC simulation by simplified PK strategy was acceptable compared to full sampling method from the analysis of archived 300 patients' data, with -5.67% of mean prediction error (MPE). Median AUC of all patients was 2.58 µg·hr/mL (range from 1.28 to 9.39). A significant correlation (P=0.007) was detected between AUC and body surface area (BSA)-dosage, but BSA contributed only 18.3% of AUC inter-individual variability. Docetaxel AUC was significantly related with the severity (grade 3-4) of neutropenia (correlation of coefficient was 0.452, P=0.004). Fourteen patients (36%) were within the target AUC range. Patients with AUC above the target experienced more severe neutropenia (grade 3-4 rate 100% vs. 56%, P=0.036; grade 4 rate 86% vs. 25%, P=0.005). No significant difference of response rate was found between patients within the target or not. CONCLUSIONS: A simplified samples PK strategy was developed for docetaxel AUC simulation. The target range of docetaxel AUC in Chinese HNC patients was suggested at 2.5-3.7 µg·hr/mL for reduced toxicity without compromising efficacy of docetaxel treatment.

Open-label, randomized study of individualized, pharmacokinetically (PK)-guided dosing of paclitaxel combined with carboplatin or cisplatin in patients with advanced non-small-cell lung cancer (NSCLC).

BACKGROUND: Variable chemotherapy exposure may cause toxicity or lack of efficacy. This study was initiated to validate pharmacokinetically (PK)-guided paclitaxel dosing in patients with advanced non-small-cell lung cancer (NSCLC) to avoid supra- or subtherapeutic exposure. PATIENTS AND METHODS: Patients with newly diagnosed, advanced NSCLC were randomly assigned to receive up to 6 cycles of 3-weekly carboplatin AUC 6 or cisplatin 80 mg/m(2) either with standard paclitaxel at 200 mg/m(2) (arm A) or PK-guided dosing of paclitaxel (arm B). In arm B, initial paclitaxel dose was adjusted to body surface area, age, sex, and subsequent doses were guided by neutropenia and previous-cycle paclitaxel exposure [time above a plasma concentration of 0.05 µM (Tc>0.05)] determined from a single blood sample on day 2. The primary end point was grade 4 neutropenia; secondary end points included neuropathy, radiological response, progression-free survival (PFS) and overall survival (OS). RESULTS: Among 365 patients randomly assigned, grade 4 neutropenia was similar in both arms (19% versus 16%; P = 0.10). Neuropathy grade ≥2 (38% versus 23%, P < 0.001) and grade ≥3 (9% versus 2%, P < 0.001) was significantly lower in arm B, independent of the platinum drug used. The median final paclitaxel dose was significantly lower in arm B (199 versus 150 mg/m(2), P < 0.001). Response rate was similar in arms A and B (31% versus 27%, P = 0.405), as was adjusted median PFS [5.5 versus 4.9 months, hazard ratio (HR) 1.16, 95% confidence interval (CI) 0.91-1.49, P = 0.228] and OS (10.1 versus 9.5 months, HR 1.05, 95% CI 0.81-1.37, P = 0.682). CONCLUSION: PK-guided dosing of paclitaxel does not improve severe neutropenia, but reduces paclitaxel-associated neuropathy and thereby improves the benefit-risk profile in patients with advanced NSCLC. CLINICAL TRIAL INFORMATION: NCT01326767 (https://clinicaltrials.gov/ct2/show/NCT01326767).

Profiles of urine samples taken from Ecstasy users at Rave parties: analysis by immunoassays, HPLC, and GC-MS.

The abuse of the designer amphetamines such as 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) is increasing throughout the world. They have become popular drugs, especially at all-night techno dance parties (Raves), and their detection is becoming an important issue. Presently, there are no MDMA- or MDA-specific immunoassays on the market, and detection of the designer amphetamines is dependent upon the use of commercially available amphetamine assays. The success of this approach has been difficult to assess because of the general unavailability of significant numbers of samples from known drug users. The objectives of the present study are to characterize the drug content of urine samples from admitted Ecstasy users by chromatographic methods and to assess the ability of the available amphetamine/methamphetamine immunoassays to detect methylenedioxyamphetamines. We found that, when analyzed by high-performance liquid chromatography with diode-array detection (HPLC-DAD), 64% of 70 urine samples (by gas chromatography-mass spectrometry [GC-MS]: 88% of 64 urine samples) obtained from Rave attendees contained MDMA and/or 3,4-methylenedioxyamphetamine (MDA) alone or in combination with amphetamine, methamphetamine, or other designer amphetamines such as 3,4-methylenedioxyethylamphetamine (MDEA). This suggests that the majority of the Ravers are multidrug users. At the manufacturer's suggested cutoffs, the Abbott TDx Amphetamine/Methamphetamine II and the new Roche HS Amphetamine/MDMA assays demonstrated greater detection sensitivity for MDMA than the other amphetamine immunoassays tested (Abuscreen OnLine Hitachi AMPS, Abuscreen OnLine Integra AMPS, Abuscreen OnLine Integra AMPSX, CEDIA AMPS, and EMIT II AMPS). There is 100% agreement between each of the two immunoassays with the reference chromatographic methods, HPLC-DAD and GC-MS, for the detection of methylenedioxyamphetamines.

Preparation of pentachlorophenol derivatives and development of a microparticle-based on-site immunoassay for the detection of PCP in soil samples.

Pentachlorophenol (PCP) is used as a herbicide in agriculture and as an insecticide for termite control. Because of the apparent hazard associated with its usage, there is a need for an efficient and economic on-site screening method. A 5-min on-site test has been developed for the detection of PCP based on the OnTrak format, a successful Roche on-site test format for drugs of abuse, utilizing the principle of latex agglutination immunoassay. The test detects 1 ppm of PCP in soil samples.

Comparison of the rates of hydrolysis of lorazepam-glucuronide, oxazepam-glucuronide and tamazepam-glucuronide catalyzed by E. coli beta-D-glucuronidase using the on-line benzodiazepine screening immunoassay on the Roche/Hitachi 917 analyzer.

The catalytic rates of hydrolysis of lorazepam-glucuronide, oxazepam-glucuronide, and temazepam-glucuronide when catalyzed by E. Coli. beta-glucuronidase both in phosphate buffer and buffered drug-free urine were compared as well as the pH dependence of enzyme activity. In 50 mM phosphate buffer pH 6.4, lorazepam-glucuronide has the highest turnover rate of 3.7 s(-1) with an associated Km of about 100 microM, followed by oxazepam-glucuronide, which has a turnover rate of 2.4 s(-1) with an associated Km of 60 microM. Temazepam-glucuronide has the lowest rate of 0.94 s(-1) with an associated Km of 34 microM. In buffered drug-free urine, a similar trend was observed. In addition, an optimal pH for beta-glucuronidase was determined to be between 6 and 7 when the enzyme hydrolyzes the benzodiazepine conjugates in buffered drug-free urine. Effects of temperature and incubation time were also examined. It can be concluded that the electron donating or withdrawing of the individual benzodiazepine structure may play an important role in the reactivity of the lorazepam-glucuronide, oxazepam-glucuronide and temazepam-glucuronide catalyzed by beta-glucuronidase. This is consistent with other observations made for monosubstituted phenyl-beta-glucuronides by Wang et al. (1).

Serum and urine concentrations of flunitrazepam and metabolites, after a single oral dose, by immunoassay and GC-MS.

A clinical study was conducted to assess the ability of commercially available immunoassays to detect flunitrazepam (FNP) in plasma and urine samples and to compare the results with those obtained by gas chromatography-mass spectrometry (GC-MS). The clinical study consisted of four individuals (two male and two female) who had taken a single 2-mg dose of FNP. Serum was collected over a 48-h period and urine was collected over a 72-h period. The serum and urine samples were analyzed by the COBAS INTEGRA Serum Benzodiazepines assay (SBENZ), the TDx serum and urine Benzodiazepines assay, and GC-MS. The GC-MS procedure was developed for analysis of FNP and metabolites in plasma and urine using an acid hydrolysis step resulting in the formation of specific benzophenones corresponding to FNP and its metabolites. The relative sensitivities of the assays for the detection of FNP and metabolites in serum and urine were GC-MS > SBENZ > TDx. The immunoassay results for serum samples showed peak concentrations of FNP metabolites at 8 h after FNP ingestion for three individuals and at about 1 h for the fourth individual. The GC-MS, SBENZ, and TDx urine immunoassays detected drug above the stated limit of detection (LOD) in 44, 41, and 35 serial FNP urine samples, respectively. FNP metabolites were detected in urine samples with all three assays for up to 72 h after a 2-mg dose. The improved detection rate with the SBENZ assay as compared to the TDx assay is likely explained by its higher cross-reactivity with the major metabolite, 7-amino-flunitrazepam (7-amino-FNP), and its lower LOD.

Investigation of nitrite adulteration on the immunoassay and GC-MS analysis of cannabinoids in urine specimens.

Nitrite ion has been identified as the active ingredient of two commercial adulterants that could cause discrepant results between the immunoassay screening and gas chromatographic-mass spectrometric (GC-MS) confirmation of 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) in urine. Procedures to chemically convert the nitrite ion at the beginning of sample preparation for GC-MS analysis may not overcome all nitrite adulteration cases because portions of the THCCOOH might have been lost between the time of sample collection and the time of analysis. This study was conducted to further investigate the influence of both urine sample matrix and the duration of nitrite exposure on nitrite interference of THCCOOH detection. Forty clinical "THC-positive samples" that had been screened and confirmed positive for the presence of THCCOOH were spiked with 0.15M or 0.3M of nitrite. The levels of THCCOOH at various time intervals after nitrite spiking were monitored by instrument-based cannabinoids immunoassays (Syva EMIT d.a.u. and/or Roche Abuscreen ONLINE assays) and by an onsite THC immunoassay (Roche ONTRAK TESTSTIK). Results from this report demonstrate that the two outstanding "urine specimen factors" that dictated the effectiveness of the nitrite adulteration were urinary pH and the original drug concentration before nitrite spiking. Significant decreases in the immunoassay results could be observed within 4 h of nitrite treatment in the majority of samples with acidic urinary pH values. Regardless of their original concentration of THCCOOH (GC-MS ranging from 33 to 488 ng/mL), all of the 20 samples that had acidic pH values gave negative immunoassay results 1 day after nitrite adulteration. In contrast, the immunoassay results of samples with neutral or basic pH values were less affected by nitrite exposure in the same studies. Approximately two-thirds of the samples with pH values greater than 7.0 remained immunoassay-positive 3 days after nitrite spiking. Nevertheless, some of the adulterated urine that showed no change in immunoassay results might exhibit significant decrease in GC-MS recoveries even with bisulfite treatment, collaborating with the observations that a portion of samples screened positive with THC immunoassay in the laboratory could fail to confirm with GC-MS analysis. The decrease or loss of immunoassay detectable cannabinoid cross-reactives in acidic "THC-positive samples" can be attenuated by chemically increasing the pH value of the samples to the basic pH range.

New fluorescence polarization immunoassays for analysis of barbiturates and benzodiazepines in serum and urine: performance characteristics.

The performance of the new fluorescence polarization immunoassay reagents Cassette COBAS INTEGRA Serum Benzodiazepines assay (SBENZ) and Cassette Serum Barbiturates assay (SBARB) was evaluated as compared to other immunoassays (Abbott TDx Serum Benzodiazepines, Abbott TDx Urine Benzodiazepines, Behring EMIT Serum Benzodiazepines, Abbott ADx Serum Barbiturates, Behring EMIT Serum Barbiturates, and the COBAS INTEGRA Barbiturates (BARB) urine assay) and gas chromatography-mass spectrometry (GC-MS). Recoveries of nordiazepam and secobarbital using the SBENZ and SBARB assays, respectively, were equivalent for serum, plasma, and urine. Cross-reactivities of structurally related benzodiazepines, barbiturates, and their metabolites were very similar in serum and urine for the SBENZ and SBARB assays. Precision was within 5.4% for SBENZ serum and within 11% from 10 to 100 ng/mL for urine. Precision was within 5% for SBARB serum and within 7% from 136 to 277 ng/mL for the urine application. The standard curves for SBENZ and SBARB were stable for at least 16 weeks with the reagents stored open on the COBAS INTEGRA analyzer. Clinical comparison of the SBENZ serum assay indicated an increased pickup rate, as confirmed by GC-MS, compared to TDx and EMIT. The diagnostic sensitivities of the SBENZ serum application, TDx, and EMIT versus GC-MS were 100%, 89%, and 36%, respectively. The diagnostic specificities were 71%, 79%, and 100%, respectively. The diagnostic sensitivities of the SBENZ urine application and TDx versus GC-MS were 100% and the diagnostic specificities were 88%. The increased positive pick-up of the SBENZ assay compared to the other immunoassays is most probably due to the difference in the limit of detection (LOD) and the increased cross-reactivity for the low-dose benzodiazepines. Clinical comparison of the SBARB serum assay indicated an increased positive pick-up rate, as confirmed by GC-MS. The diagnostic sensitivities of the SBARB serum application, ADx, and EMIT versus GC-MS were 96%, 65%, and 35%, respectively. The diagnostic specificities were all 100%. The diagnostic sensitivities for the SBARB urine application and BARB versus GC-MS were all 100%, and the diagnostic specificities were all 91%. The SBENZ and SBARB kits demonstrated increased sensitivity for the detection of benzodiazepines and barbiturates in both serum and urine compared to the other immunoassays.

GC-MS determination of flunitrazepam and its major metabolite in whole blood and plasma.

A gas chromatography-mass spectrometry method was developed for the analysis of flunitrazepam (FN) and its major metabolite, 7-amino-flunitrazepam (7-amino-FN), in both plasma and whole blood. The method was based on acid hydrolysis of the samples after dilution with HPLC water followed by extraction and derivatization (heptafluorobutyrate) of the resulting benzophenones. Analysis of plasma and whole blood samples from subjects administered 2-mg doses of FN showed that FN was only detected in whole blood (LOD 5 ng/mL) and not in plasma. However, 7-amino-FN was detected in both plasma and whole blood, although the levels were much higher in plasma. 7-Amino-FN was detected for the entire period of specimen collection (12 h), but FN was only detected in whole blood for 4 h after ingestion with peak levels after 1 h.

Prevalence of drugs used in cases of alleged sexual assault.

In recent years, there has been an increase in the number of reports in the U.S. of the use of drugs, often in conjunction with alcohol, to commit sexual assault. A study was undertaken to assess the prevalence of drug use in sexual assault cases in which substances are suspected of being involved. Law enforcement agencies, emergency rooms, and rape crisis centers across the U.S. were offered the opportunity to submit urine samples collected from victims of alleged sexual assault, where drug use was suspected, for analysis of alcohol and drugs which may be associated with sexual assault. Each sample was tested by immunoassay for amphetamines, barbiturates, benzodiazepines, cocaine metabolite (benzoylecgonine), cannabinoids, methaqualone, opiates, phencyclidine and propoxyphene. The positive screen results were confirmed by gas chromatography-mass spectroscopy (GC-MS). In addition, each sample was tested for flunitrazepam metabolites and gamma-hydroxybutyrate (GHB) by GC-MS and for ethanol by gas chromatography-flame ionization detection (GC-FID). Over a 26-month period, 1179 samples were collected and analyzed from 49 states, Puerto Rico, and the District of Columbia. The states sending the most samples were California (183), Texas (119), Florida (61), Pennsylvania (61), New York (61), Minnesota (50), Illinois (47), Indiana (44), Michigan (40), Maryland (37), Virginia (32), and Massachusetts (31). Four-hundred sixty eight of the samples were found negative for all the substances tested; 451 were positive for ethanol, 218 for cannabinoids, 97 for benzoylecgonine, 97 for benzodiazepines, 51 for amphetamines, 48 for GHB, 25 for opiates, 17 for propoxyphene, and 12 for barbiturates. There were no samples identified as positive for phencyclidine or methaqualone. In addition, 35% of the drug-positive samples contained multiple drugs. This study indicates that, with respect to alleged sexual assault cases, the prevalence of ethanol is very high, followed by cannabinoids, cocaine, benzodiazepines, amphetamines, and GHB. Although only a couple of substances have been implicated with sexual assault, this study has shown that almost 20 different substances have been associated with this crime. This study also raises the concern of illicit and licit drug use in sexual assault cases and suggests the need to test for a range of drugs in these cases. It also highlights the need to test for GHB, which is not generally tested for in a normal toxicology screen.

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.

Stability study of LSD under various storage conditions.

A controlled study was undertaken to determine the stability of LSD in pooled urine samples. The concentrations of LSD in urine samples were followed over time at various temperatures, in different types of storage containers, at various exposures to different wavelengths of light, and at varying pH values. LSD concentrations were measured quantitatively by the Abuscreen RIA and by HPLC using a fluorescence detection method. Good correlation was observed between the immunoassay and the fluorescent integrity of the LSD molecule. Thermostability studies were conducted in the dark with various containers. These studies demonstrated no significant loss in LSD concentration at 25 degrees C for up to 4 weeks. After 4 weeks of incubation, a 30% loss in LSD concentration at 37 degrees C and up to a 40% at 45 degrees C were observed. Urine fortified with LSD and stored in amber glass or nontransparent polyethylene containers showed no change in concentration under any light conditions. Stability of LSD in transparent containers under light was dependent on the distance between the light source and the samples, the wavelength of light, exposure time, and the intensity of light. After prolonged exposure to heat in alkaline pH conditions, 10 to 15% of the parent LSD epimerized to iso-LSD. Under acidic conditions, less than 5% of the LSD was converted to iso-LSD. We also demonstrated that trace amounts of metal ions in buffer or urine could catalyze the decomposition of LSD and that this process can be avoided by the addition of EDTA. This study demonstrates the importance of proper storage conditions of LSD in urine in order to insure proper analytical testing results over time.

A non-cannabinoid immunogen used to elicit antibodies with broad cross-reactivity to cannabinoid metabolites.

A benzpyran derivative was linked to the lysines of bovine thyroglobulin (BTG) where 69% of the available lysines were modified. This derivative was designed to elicit antibodies that were directed towards the conserved epitopes of cannabinoid metabolites that appear in urine. Polyclonal antibodies from sheep and goats and murine monoclonal antibodies were generated using this immunogen. The cross-reactivity of the antibodies was compared with antibodies generated from the more traditional phenolic-linked or 9-linked immunogens. An ELISA assay was developed using delta 9-11-nor-9-carboxy-tetrahydrocannabinol (COOH-THC) to obtain a standard curve. The antibodies generated using the benzpyran immunogen showed an average of two to three times higher cross-reactivity towards 11-OH-delta 9-THC, 8 beta-OH-delta 9-THC, 8 alpha-OH-delta 9-THC, 11-OH-delta 8-THC, and 8 beta,11-di-OH-delta 9-THC than antibodies that were generated by traditional cannabinoid immunogens. The selectivity of the benzpyran-elicited antibodies was also compared with antibodies derived from traditional immunogens using clinical urine samples that were confirmed for cannabinoids by GC/MS. The total cross-reactive cannabinoid values obtained with the benzpyran-elicited antibodies were 49% higher than the values obtained using the traditional immunogen structures. The benzpyran immunogen-induced antibodies exhibited the same low cross-reactivity for non-structurally related compounds as antibodies derived from traditional immunogens. The novel benzpyran immunogen used in this study is the first non-cannabinoid immunogen used to generate cannabinoid-selective antibodies and demonstrates the usefulness of such a structure in developing broadly cross-reactive cannabinoid antibodies.

Generation of carbohydrate-deficient transferrin by enzymatic deglycosylation of human transferrin.

Carbohydrate-deficient transferrin (CDT) molecules are transferrin isoforms that lack one or both of the carbohydrate groups attached to a normal human transferrin molecule. CDT has been reported to be a sensitive and specific marker for diagnosing alcoholism. This report demonstrates the in vitro generation of CDT molecules that can potentially be used as the standard in measuring CDT concentrations. This was achieved by deglycosylation of human transferrin with the enzyme Endo-beta-N-acetylglucosaminidase F2 (Endo-F2). The enzyme was immobilized on sepharose beads, which were packed into a column. The immobilization of the enzyme not only eliminated the Endo-F2 contamination of CDT, but also rendered the enzyme suitable for repetitive use. In this manner, it was possible to obtain at least 200 mg of CDT over a period of more than 3 mo, without any noticeable decrease of enzyme activity, using only 3.0 micrograms of enzyme. This proved to be an efficient method for generating CDT.

New synthesis and characterization of (+)-lysergic acid diethylamide (LSD) derivatives and the development of a microparticle-based immunoassay for the detection of LSD and its metabolites.

In this paper are reported the synthesis and characterization of three LSD derivatives. On the basis of several analytical characterization studies, the most stable derivative has been selected and a procedure to covalently link the derivative to polystyrene microparticles through a carrier protein has been developed. In addition, two new LSD immunogens have been synthesized and characterized, and from these immunogens antibodies that recognize not only LSD but also several major LSD metabolites have been generated. Using the selected derivative and antibody, a homogeneous microparticle-based immunoassay has been developed for the detection of LSD in human urine with the required sensitivity and specificity for an effective screening assay. The performance of this LSD OnLine assay has been evaluated using the criteria of precision, cross-reactivity, correlation to the Abuscreen LSD RIA and GC/MS/MS, assay specificity, and limit of detection.

Epimerization studies of LSD using 1H nuclear magnetic resonance (NMR) spectroscopy.

A study was conducted to determine the conditions needed to achieve the equilibrium concentration for the epimerization of d-lysergic acid diethylamide (LSD) to iso-LSD. The reaction was followed by integration of the C-9 resonance of LSD and iso-LSD by proton nuclear magnetic resonance (NMR). The C-9 resonance of LSD and iso-LSD appear as singlets at 6.35 and 6.27 ppm respectively. Starting with pure LSD, the conversion to iso-LSD is attained at temperatures above 37 degrees C and pH levels over 7.0. At a pH of 7.0 or higher, the LSD/iso-LSD ratio of 9:1 is achieved after one week at 45 degrees C or two weeks at 37 degrees C. Starting with iso-LSD, the conversion to LSD requires more vigorous conditions. The 9:1 LSD/iso-LSD ratio is attained only after 6 weeks at a temperature of 45 degrees C and a pH of 9.7. At lower pH levels, the reaction proceeds more slowly. The 9:1 LSD/iso-LSD ratio is achieved whether the starting material is LSD or iso-LSD and therefore represents an equilibrium concentration (K = 9). In addition, the more vigorous conditions needed to achieve equilibrium of iso-LSD to LSD demonstrate the difficulty in extraction of the epimerizable proton of iso-LSD. This study is the first to quantitate the epimerization of LSD by NMR techniques and establishes the conditions needed to induce epimerization in solution.

A sensitive GC-MS procedure for the analysis of flunitrazepam and its metabolites in urine.

Analysis of urine specimens collected from individuals ingesting 2 and 4 mg flunitrazepam (FN) showed positive results by OnLine and OnTrak immunoassays for up to 60 h. Gas chromatographic-mass spectrometric (GC-MS) analysis of these specimens for FN, 3-OH-FN, 7-amino-FN, 7-amino-3-OH-FN, desmethyl-FN, and 3-OH-desmethyl-FN after glucuronidase treatment showed only low levels of 7-amino-FN with almost none of the other metabolites. These levels were far below the expected results based on the immunoassay data. This study reports on a GC-MS procedure for FN and the previously listed metabolites. The method is based on acid hydrolysis of the urine specimens, which converts FN and all its metabolites described previously to one of four amino-benzophenone derivatives (1-4) with oxazepam-d5 as the internal standard. Under the experimental conditions, the internal standard is converted to 2-amino-5-chloro-benzophenone-d5. The limit of detection for 7-amino-FN and 7-amino-desmethyl-FN and their 3-OH derivatives was less than 1 ng/mL. Analysis of urine specimens collected for 72-h postingestion of 1, 2, or 4 mg FN showed appreciable levels of benzophenone 3 (product of 7-amino-FN and 7-amino-3-OH-FN) and lower levels of benzophenone 4 (product of 7-amino-desmethyl-FN and 7-amino-3-OH-desmethyl-FN) with no detectable levels of benzophenones 1 and 2. The method makes it possible to confirm the presence of FN metabolites in urine at least 72-h postingestion of small doses of the drug.

Flunitrazepam excretion patterns using the Abuscreen OnTrak and OnLine immunoassays: comparison with GC-MS.

A study was conducted to compare the performance of the OnLine and OnTrak immunoassays for benzodiazepines with gas chromatographic-mass spectrometric (GC-MS) analysis in detecting flunitrazepam (FNP) and its metabolites in human urine. Urine was collected over a 72-h period from six individuals (four male and two female) who had taken a single oral dose of either 1 or 4 mg of FNP. The OnTrak assay was run at a 100-ng/mL cutoff of nordiazepam (NDP), and the OnLine assay was run with a standard curve from zero to 200 ng/mL of NDP with and without beta-glucuronidase treatment. Each sample was analyzed by GC-MS using FNP, 7-amino-FNP, 3-hydroxy-FNP, desmethyl-FNP, 7-amino-3-hydroxy-FNP, and desmethyl-3-hydroxy-FNP as standards with beta-glucuronidase treatment. The specimens from the 1-mg dose did not yield a positive result by immunoassay over the 72-h collection period. Specimens from the 4-mg dose did yield positive results in both immunoassays. The time of the first positive result ranged from 4 to 12 h, and the time to the last positive result ranged from 18 to 60 h. Treatment of the samples with beta-glucuronidase increased the OnLine values between 20 and 60%, but it did not appreciably increase the detection time. GC-MS analysis showed no detectable levels of FNP, 3-hydroxy-FNP, desmethyl-FNP, 7-amino-3-hydroxy-FNP, and desmethyl-3-hydroxy-FNP. However, all samples collected past time zero showed detectable levels of 7-amino-FNP (> 2 ng/mL) with peak concentrations at 12-36 h. The peak levels of 7-amino-FNP by GC-MS paralleled the peak levels of the immunoassay response. The amount of 7-amino-FNP metabolite quantitated by GC-MS, however, accounted for only 15-20% of the total immunoassay crossreactive FNP metabolites.

Synthesis of new d-propoxyphene derivatives and the development of a microparticle-based immunoassay for the detection of propoxyphene and norpropoxyphene.

The synthesis of [S-(R,S)]-4-[[methyl[2-methyl-3-(1-oxopropoxy)-3, 4-diphenylbutyl]amino]-1-oxobutoxy]-2,5-pyrrolidinedione+ ++ (propoxyphene active ester, 2) is described. This was used as an intermediate to prepare a propoxyphene immunogen, [S-(R,S)]-4-[methyl][2-methyl-3-(1-oxopropoxy)-3,4-diphenylbuty l]-amino]- 1-oxobutyl-Bovine Thyroglobulin (3). This immunogen was then used to generate antibodies which demonstrate good cross-reactivity to d-propoxyphene, d-norpropoxyphene, and other propoxyphene metabolites. In addition, these antibodies were shown to have very low cross-reactivity to methadone, a structurally related compound. The introduction of an aminomethyl benzoate spacer into the propoxyphene active ester (2), followed by the activation of the carboxylic acid, provided for a more stable active ester (5). This stable active ester, together with the antibodies generated from the propoxyphene immunogen, has led to the development of an immunoassay based on the Kinetic Interaction of Microparticles in Solution (KIMS).

Evaluation of the online immunoassay for propoxyphene: comparison to EMIT II and GC-MS.

A study was conducted to compare the clinical sensitivity of the OnLine and EMIT II assays for propoxyphene (PPX) use in human urine. A total of 5138 random clinical samples were evaluated by both OnLine and EMIT II. Samples that were positive for each immunoassay were confirmed for PPX and norpropoxyphene (NPPX) by gas chromatography-mass spectrometry (GC-MS). There were 14 samples that were identified positive by both immunoassays and confirmed positive by GC-MS. An additional six samples were positive by OnLine, negative by EMIT II, and confirmed positive by GC-MS. There was one unconfirmed positive sample identified by each immunoassay, and 5116 samples were identified as negative by both immunoassays. The increased sensitivity by OnLine can be attributed to the cross reactivity of the OnLine antibody, which is higher than the cross reactivity of the EMIT II antibody for NPPX (77% versus 7%, respectively). The high concentrations of NPPX, relative to those of PPX, found in all of the clinical samples suggest that laboratories that currently confirm for PPX should confirm for NPPX in order to obtain a better correlation between immunoassay results and GC-MS confirmations.