ABSTRACT
BACKGROUND: According to the guidelines, benzodiazepines with a short half-life are the reference medication to treat alcohol withdrawal syndrome. The doses of oxazepam used in this population may reach up to 300 mg per day, significantly higher than usual doses. Its use in these patients deserves further information to confirm that the half-life remains constant and that no accumulation appears. The objective of this study was to investigate the pharmacokinetics of high doses of oxazepam in alcohol-dependent patients treated for alcohol withdrawal syndrome. METHODS: Overall, 63 outpatients [weight, 71.1 kg (45.0-118.0); age, 47.6 years (31-67)] followed in the addictology unit, were studied. Total mean dose of 96.0 mg per day (range, 20-300 mg/d) was administered by oral route. Therapeutic drug monitoring allowed the measurement of 96 plasma concentrations. The following covariates were evaluated: demographic data (age, body weight, height, gender) and biological data (creatinine, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transferase). Pharmacokinetic analysis was performed using a nonlinear mixed-effect population model. RESULTS: Data were modeled with a 1-compartment pharmacokinetic model. The population typical mean 90% confidence interval values for clearance, apparent volume of distribution (V), and duration of absorption (D1) were 6.8 L/h (range, 3.9-8.0 L/h), 159 L (range, 98.0-282 L), and 2 hours (fixed), respectively. The interindividual variability of clearance and V, and residual variability (90% confidence interval) were 74% (44%-96%), 69% (40%-89%), and 32% (20%-41%), respectively. The elimination half-life was 16 hours (range, 3-42 hours). CONCLUSIONS: Oxazepam exhibited a linear pharmacokinetics with a proportional relationship from 20 to 300 mg per day, the dose range currently used in alcohol-dependent patients treated for alcohol withdrawal syndrome. We did not find any evidence of drug accumulation with these doses.
Subject(s)
Alcoholism/drug therapy , Ethanol/adverse effects , Oxazepam/administration & dosage , Oxazepam/pharmacokinetics , Substance Withdrawal Syndrome/drug therapy , Administration, Oral , Adult , Aged , Alcoholism/blood , Body Weight/drug effects , Drug Monitoring/methods , Female , Half-Life , Humans , Male , Middle Aged , Models, Biological , Nonlinear Dynamics , Oxazepam/blood , Risk , Substance Withdrawal Syndrome/bloodABSTRACT
A quantitative method using ultra performance liquid chromatography-tandem mass spectrometry is described for simultaneous determination of nicotine and its metabolites (cotinine and trans-3'- hydroxycotinine) in human plasma. Aliquots of 0.25 mL of plasma specimens were used for analysis, and 3 analytes were extracted by liquid-liquid extraction. The main problem was blank plasma contamination with environmental nicotine. Activated charcoal was used to avoid this analytical interference. For optimized chromatographic performance, a basic mobile phase consisting of 0.2% ammonia in water (mobile phase A, pH10.6) and acetonitrile (mobile phase B) was selected. The analytes were separated on a 50 mm × 2.1 mm BEH C18 column, 1.7 µm particle size, and quantified by MS/MS using multiple-reaction monitoring (MRM) in positive mode. The chromatographic separation was achieved in 3 min followed by 1.2 min of column equilibration. The calibration curves were linear in the concentration range of 10-1000 ng/mL with correlation coefficients exceeding 0.99. Within-day precisions and between-day precisions (CV, %) were <15 %. The accuracy expressed as bias was within ±15% for all analytes. The recovery values ranged from 50% to 97%. The ions used for quantification of nicotine, cotinine and 3-OH-cotinine were 166.9 > 129.7; 176.9 > 79.7; 192.9 > 79.7 m/z, respectively. The original blank sample preparation solved the problem of contamination in a cost-effective and efficient way. The validated method has been routinely used for analysis of nicotine and metabolites and determination of hydroxycotinine/cotinine metabolic ratio. This biomarker seems to be interesting at predicting response of nicotine patch replacement therapies.
Subject(s)
Chromatography, Liquid/methods , Cotinine/analogs & derivatives , Nicotine/blood , Nicotinic Agonists/blood , Tandem Mass Spectrometry , Tobacco Use Cessation Devices , Administration, Cutaneous , Adolescent , Adult , Aged , Aged, 80 and over , Biotransformation , Calibration , Charcoal/chemistry , Chromatography, Liquid/standards , Cotinine/blood , Female , Humans , Liquid-Liquid Extraction , Male , Middle Aged , Nicotine/administration & dosage , Nicotinic Agonists/administration & dosage , Reference Standards , Reproducibility of Results , Smoking Cessation/methods , Tandem Mass Spectrometry/standards , Transdermal Patch , Young AdultABSTRACT
A 2D colorimetric DNA sensor is reported based on the 2D aggregation of oligonucleotide-modified gold nanoparticle probes resulting from the molecular hybridization between these latest and their complementary single stranded DNA targets. To increase their mobility the nanoparticles are adsorbed on a fluid lipid bilayer, itself supported on a substrate. The hybridization between the target and the mobile nanoparticle probes creates links between the nanoparticles resulting in the formation of nanoparticle aggregates in the plane of the substrate. This aggregation is detected using a new method based on the selective desorption of non-aggregated nanoparticles. The addition of dextran sulfate induces the substitution of non-aggregated gold nanoparticles while aggregated ones are stable on the substrate. We show that this detection method is highly specific and allows the detection of DNA mismatches and damages.
