Liquid chromatographic method for simultaneous determination of alprazolam with NSAIDs in bulk drug, pharmaceutical formulation and human serum.

High performance liquid chromatography with UV/vis detection was optimized and validated for simultaneous quantification of alprazolam with celecoxib and diclofenac sodium in pharmaceutical formulation and human serum. Chromatographic separation was achieved at detection wavelength of 230 nm on Shimadzu Shim-pack CLC-ODS (M) 25M column employing 80:20 (v/v) methanol: water (pH 3.5) as mobile phase with elution rate 1.0mL min-1. Analytes were quantified in the ranges 0.2-15, 0.3-20 and 0.6-40 µg mL-1 with detection limits 19.76, 17.29 and 11.83ng mL-1 respectively. Recoveries were in the range 98.15-101.15, 99.24-99.90 and 98.87-101.19% in pharmaceutical formulation and 98.05-101.01, 98.72-99.49 and 98.25-99.47% in human serum respectively and precision ranged from 0.19-1.84%. The analytes were successfully detected without any observable interference commonly present in pharmaceutical formulation and human serum demonstrating applicability of method.

A comparative study for detecting CYP3A induction by CYP3A probe drugs and endogenous markers in cynomolgus monkeys.

CYP3A probe drugs such as midazolam and endogenous markers, and plasma 4ß-hydroxycholesterol (4ß-OHC) and urinary 6ß-hydroxycortisol-to-cortisol ratios (6ß-OHC/C) have been used as markers of CYP3A induction in cynomolgus monkeys, as with humans. However, there is limited information on their sensitivity and ability to detect CYP3A induction, as most studies were evaluated only at a high dose of the inducer, rifampicin (RIF; 20 mg/kg). In the present study, the CYP3A induction by RIF over a range doses of 0.2, 2 and 20 mg/kg (n = 4) was examined using CYP3A probe drugs (midazolam, triazolam and alprazolam) and the plasma and urinary endogenous CYP3A markers (4ß-OHC and 6ß-OHC/C). The sensitivity and relationship for detecting CYP3A induction was compared among the markers. Four days repeated oral administration of rifampicin to cynomolgus monkeys reduced the area under the plasma concentration-time curve of all CYP3A probe drugs in a rifampicin dose-dependent manner. Although the endogenous CYP3A markers (4ß-OHC and 6ß-OHC/C) were also changed for the middle (2 mg/kg) and high (20 mg/kg) doses of rifampicin, the fold-changes were relatively small, and CYP3A induction could not be detected at the lowest dose of rifampicin (0.2 mg/kg). In conclusion, CYP3A probe drugs are more sensitive for detecting CYP3A induction than endogenous CYP3A markers in cynomolgus monkeys, even for a short experimental period.

Development of a Paper Spray Mass Spectrometry Cartridge with Integrated Solid Phase Extraction for Bioanalysis.

A novel paper spray cartridge with an integrated solid phase extraction (SPE) column is described. The cartridge performs extraction and pre-concentration, as well as sample ionization by paper spray, from complex samples such as plasma. The cartridge allows for selective enrichment of target molecules from larger sample volumes and removal of the matrix, which significantly improved the signal intensity of target compounds in plasma samples by paper spray ionization. Detection limits, quantitative performance, recovery, ionization suppression, and the effects of sample volume were evaluated for five drugs: carbamazepine, atenolol, sulfamethazine, diazepam, and alprazolam. Compared with direct paper spray analysis of dried plasma spots, paper spray analysis using the integrated solid phase extraction improved the detection limits significantly by a factor of 14-70, depending on the drug. The improvement in detection limits was, in large part, due to the capability of analyzing larger sample volumes. In addition, ionization suppression was found to be lower and recovery was higher for paper spray with integrated SPE, as compared to direct paper spray analysis. By spiking an isotopically labeled internal standard into the plasma sample, a linear calibration curve for the drugs was obtained from the limit of detection (LOD) to 1 µg/mL, indicating that this method can be used for quantitative analysis. The paper spray cartridge with integrated SPE could prove valuable for analytes that ionize poorly, in applications where lower detection limits are required, or on portable mass spectrometers. The improved performance comes at the cost of requiring a more complex paper spray cartridge and requiring larger sample volumes than those used in typical direct paper spray ionization.

Poor Man's Methadone: A Case Report of Loperamide Toxicity.

Loperamide, a common over-the-counter antidiarrheal drug and opioid derivative, is formulated to act upon intestinal opioid receptors. However, at high doses, loperamide crosses the blood-brain barrier and reaches central opioid receptors in the brain, leading to central opiate effects including euphoria and respiratory depression. We report the case of a young man found dead in his residence with a known history of drug abuse. At autopsy, the only significant findings were a distended bladder and bloody oral purge. Drug screening found nontoxic levels of alprazolam, fluoxetine, and marijuana metabolites. Liquid chromatography time-of-flight mass spectrometry found an unusual set of split isotope peaks consistent with chlorine. On the basis of autopsy and toxicological findings, loperamide toxicity was suspected because of its opioid properties and molecular formula containing chlorine. A sample of loperamide was analyzed by liquid chromatography time-of-flight mass spectrometry, resulting in a matching mass and retention time to the decedent's sample. Subsequently, quantitative testing detected 63 ng/mL of loperamide or more than 6 times of therapeutic peak concentration. Cause of death was determined as "toxic effects of loperamide with fluoxetine and alprazolam." Because of its opioid effects and easy accessibility, loperamide is known as "poor man's methadone" and may go undetected at medical and forensic drug screening.

Pharmacokinetics and physiologic effects of alprazolam after a single oral dose in healthy mares.

The objective of this study was to evaluate the pharmacokinetic properties and physiologic effects of a single oral dose of alprazolam in horses. Seven adult female horses received an oral administration of alprazolam at a dosage of 0.04 mg/kg body weight. Blood samples were collected at various time points and assayed for alprazolam and its metabolite, α-hydroxyalprazolam, using liquid chromatography/mass spectrometry. Pharmacokinetic disposition of alprazolam was analyzed by a one-compartmental approach. Mean plasma pharmacokinetic parameters (±SD) following single-dose administration of alprazolam were as follows: Cmax 14.76 ± 3.72 ng/mL and area under the curve (AUC0-∞ ) 358.77 ± 76.26 ng·h/mL. Median (range) Tmax was 3 h (1-12 h). Alpha-hydroxyalprazolam concentrations were detected in each horse, although concentrations were low (Cmax 1.36 ± 0.28 ng/mL). Repeat physical examinations and assessment of the degree of sedation and ataxia were performed every 12 h to evaluate for adverse effects. Oral alprazolam tablets were absorbed in adult horses and no clinically relevant adverse events were observed. Further evaluation of repeated dosing and safety of administration of alprazolam to horses is warranted.

Metabolism of alprazolam (a marker of CYP3A4) in hemodialysis patients with persistent inflammation.

OBJECTIVE: To investigate the impact of persistent inflammation in hemodialysis (HD) patients on the pharmacokinetics of alprazolam, a cytochrome P450 (CYP) 3A4 substrate, and its metabolites and the role of HD in the impact of persistent inflammation in this clinical context. METHODS: The study population comprised 26 HD patients (mean age 64 years, range 27-79 years; 19 men, 7 women) who were given 1 mg of alprazolam orally in the evening before the day of HD. Unconjugated and conjugated alprazolam and its 4-hydroxy and α-hydroxy metabolites were measured by liquid chromatography-mass spectrometry at 10, 34 (start of HD) and 38 (end of HD) h after intake. C-reactive protein (CRP) was measured weekly beginning 2 months before study initiation, and alpha 1-acid glycoprotein and 4ß-hydroxycholesterol were measured at baseline. CYP3A4 activity was estimated as the ratio of unconjugated alprazolam to 4-hydroxyalprazolam between 10 and 34 h following alprazolam intake. RESULTS: After a single dose of alprazolam, plasma concentrations of unconjugated alprazolam and its metabolites decreased gradually, and unconjugated 4-hydroxyalprazolam was eliminated more rapidly than unconjugated alprazolam by HD. In contrast, the plasma concentrations of conjugated alprazolam and its conjugated metabolites increased during the 34 h following drug intake and the subsequent HD decreased their levels by almost 80%. The ratio of unconjugated alprazolam to 4-hydroxyalprazolam was correlated with CRP levels (r(s) = 0.49, P = 0.01). There was no significant correlation between CYP3A4 activity measured by alprazolam (4-hydroxylation) and alpha 1-acid glycoprotein or 4ß-hydroxycholesterol. Conjugated alprazolam was also found in the plasma. CONCLUSIONS: The correlation between CYP3A4 activity (assessed by alprazolam 4-hydroxylation) and CRP level suggests that inflammation may downregulate CYP3A4 activity. If confirmed, this could have major implications for drug dosing in persistently inflamed patients.

A novel microextraction by packed sorbent-gas chromatography procedure for the simultaneous analysis of antiepileptic drugs in human plasma and urine.

A simple, accurate, and sensitive microextraction by packed sorbent-gas chromatography-mass spectrometry method has been developed for the simultaneous quantification of four antiepileptic drugs; oxcarbazepine, carbamazepine, phenytoin, and alprazolam in human plasma and urine as a tool for drug monitoring. Caffeine was used as internal standards for the electron ionization mode. An original pretreatment procedure on biological samples, based on microextraction in packed syringe using C(18) as packing material gave high extraction yields (69.92-99.38%), satisfactory precision (RSD < 4.7%) and good selectivity. Linearity was found in the 0.1-500 ng/mL range for these drugs with limits of detection (LODs) between 0.0018 and 0.0036 ng/mL. Therefore, the method has been found to be suitable for the therapeutic drug monitoring of patients treated with oxcarbazepine, carbamazepine, phenytoin, and alprazolam. After validation, the method was successfully applied to some plasma samples from patients undergoing therapy with one or more of these drugs. A comparison of the detection limit with similar methods indicates high sensitivity of the present method over the earlier reported methods. The present method is applied for the analysis of these drugs in the real urine and plasma samples of the epileptic patients.

Drug effect on EEG connectivity assessed by linear and nonlinear couplings.

Quantitative analysis of human electroencephalogram (EEG) is a valuable method for evaluating psychopharmacological agents. Although the effects of different drug classes on EEG spectra are already known, interactions between brain locations remain unclear. In this work, cross mutual information function and appropriate surrogate data were applied to assess linear and nonlinear couplings between EEG signals. The main goal was to evaluate the pharmacological effects of alprazolam on brain connectivity during wakefulness in healthy volunteers using a cross-over, placebo-controlled design. Eighty-five pairs of EEG leads were selected for the analysis, and connectivity was evaluated inside anterior, central, and posterior zones of the scalp. Connectivity between these zones and interhemispheric connectivity were also measured. Results showed that alprazolam induced significant changes in EEG connectivity in terms of information transfer in comparison with placebo. Trends were opposite depending on the statistical characteristics: decreases in linear connectivity and increases in nonlinear couplings. These effects were generally spread over the entire scalp. Linear changes were negatively correlated, and nonlinear changes were positively correlated with drug plasma concentrations; the latter showed higher correlation coefficients. The use of both linear and nonlinear approaches revealed the importance of assessing changes in EEG connectivity as this can provide interesting information about psychopharmacological effects.

Alprazolam as an in vivo probe for studying induction of CYP3A in cynomolgus monkeys.

Induction of the cytochrome P450 (P450) enzyme is a major concern in the drug discovery processes. To predict the clinical significance of enzyme induction, it is helpful to investigate pharmacokinetic alterations of a coadministered drug in a suitable animal model. In this study, we focus on the induction of CYP3A, which is involved in the metabolism of approximately 50% of marketed drugs and is inducible in both the liver and intestine. As a marker substrate for CYP3A activity, alprazolam (APZ) was selected and characterized using recombinant CYP3A enzymes expressed in Escherichia coli. Both human CYP3A4 and its cynomolgus P450 ortholog predominantly catalyzed APZ 4-hydroxylation with sigmoidal kinetics. When administered intravenously and orally to cynomolgus monkeys, APZ had moderate clearance; its first-pass extraction ratio after oral dosing was estimated to be 0.09 in the liver and 0.45 in the intestine. Pretreatment with multiple doses of rifampicin (20 mg/kg p.o. for 5 days), a known CYP3A inducer, significantly decreased plasma concentrations of APZ after intravenous and oral administrations (0.5 mg/kg), and first-pass extraction ratios were increased to 0.39 in the liver and 0.63 in the intestine. The results were comparable to those obtained in clinical drug-drug interaction (DDI) reports related to CYP3A induction, although the rate of recovery of CYP3A activity seemed to be slower than rates estimated in clinical studies. In conclusion, pharmacokinetic studies using APZ as a probe in monkeys may provide useful information regarding the prediction of clinical DDIs due to CYP3A induction.

Single-step extraction for simultaneous quantification of desvenlafaxine and alprazolam in human spiked plasma by RP-HPLC.

Desvenlafaxine (DES) and Alprazolam (ALP) are the drugs commonly prescribed together for the treatment of Major Depressive Disorders (MDD). A literature survey revealed, there is no method for the simultaneous determination of these two drugs. The purpose of this research was to develop and validate a simple, accurate, precise, robust, and isocratic RP-HPLC method for simultaneous determination of DES and ALP in human spiked plasma using UV-detector in short analysis time. The method utilized Hypersil BDS C18 (250 mm×4.6 mm, 5 µm) through an isocratic mode of elution using HPLC grade acetonitrile and 0.02M KH2PO4 buffer (65:35) and 0.1% Tri Fluoro Acetic acid (TFA) with pH 4.00 adjusted with 1M KOH. The flow rate was 1.00 mLmin-1 and elution of the drugs was monitored at 230nm. The elution time of DES and ALP was 4.011 and 5.182 minutes respectively. The method was linear for the concentration range 10-150 µgmL-1 for DES and 5.0-75.0 µgmL-1 for ALP. According to the validation results, the method is sensitive with Limit of Detection (LOD) 4.740 µgmL-1 and Limit of Quantification (LOQ) of 14.365 µgmL-1 for DES and LOD 1.891 µgmL-1 & LOQ 5.730 µgmL-1 for ALP. The reproducibility of results with minute deliberate variations in method parameters has proven that the method is robust. The data from stability studies show a non-significant change in drugs solutions for 2 months. The optimized method was validated as per International Conference for Harmonisation (ICH) Q2(R1) guidelines. This method can be used for the estimation of DES and ALP in plasma and can evaluate pharmacokinetic parameters of both drugs simultaneously.

Effects of plasma concentration of micro-RNA Mir-27b and CYP3A4*22 on equilibrium concentration of alprazolam in patients with anxiety disorders comorbid with alcohol use disorder.

Alprazolam is used in the treatment of patients with anxiety disorders comorbid with alcohol use disorder. Some proportion of these patients does not respond adequately to treatment with alprazolam, while many of them experience dose-dependent adverse drug reactions. Results of the previous studies have shown that CYP3A is involved in the biotransformation of alprazolam, the activity of which is dependent, inter alia, on the polymorphism of the encoding gene. OBJECTIVE: The objective of our study was to investigate the effect of 99366316G>A polymorphism of the CYP3A4 gene on the concentration/dose indicator of alprazolam in patients with anxiety disorders comorbid with alcohol use disorder, using findings on enzymatic activity of CYP3A (as evaluated by the 6-beta-hydroxy-cortisol/cortisol ratio measurement) and on CYP3A4 expression level obtained by measuring the miR-27b plasma concentration levels in patients with anxiety disorders comorbid with alcoholism. MATERIAL AND METHODS: Our study enrolled 105 patients with anxiety disorders comorbid with alcohol use disorder (age - 37.8±14.6 years). Therapy included alprazolam in an average daily dose of 5.6±2.4 mg per day. Treatment efficacy was evaluated using the psychometric scales. Therapy safety was assessed using the UKU Side-Effect Rating Scale. For genotyping and estimation of the microRNA (miRNA) plasma levels, we performed the real-time polymerase chain reaction. The activity of CYP3A was evaluated using the HPLC-MS/MS method by the content of the endogenous substrate of the given isoenzyme and its metabolite in urine (6- beta-hydroxy-cortisol/cortisol). Therapeutic drug monitoring (TDM) has been performed using HPLC-MS/MS. RESULTS: Our study revealed the statistically significant results in terms of the treatment efficacy evaluation (HAMA scores at the end of the treatment course): (GG) 3.0 [2.0; 5.0] and (GA) 4.0 [4.0; 5.0], p = 0.007; at the same time, the statistical significance in the safety profile was not obtained (the UKU scores): (GG) 3.0 [2.0; 3.8] and (GA) 3.0 [1.5; 4.0], p = 0.650. We revealed a statistical significance for concentration/dose indicator of alprazolam in patients with different genotypes: (GG) 1.583 [0.941; 2.301] and (GA) 2.888 [2.305; 4.394], p = 0.001). Analysis of the results of the pharmacotranscriptomic part of the study didn't show the statistically significant difference in the miR-27b plasma levels in patients with different genotypes: (GG) 25.6 [20.4; 28.8], (GA) 25.7 [19.7; 33.1], p = 0.423. At the same time, correlation analysis revealed a statistically significant relationship between the alprazolam efficacy profile evaluated by changes in HAMA scale scores and the miR-27b plasma concentration: rs = 0.20, p = 0.042. Also, we didn't reveal the correlation between the miRNA concentration and safety profile: rs = 0.15, p = 0.127. In addition, we revealed the relationship between the CYP3A enzymatic activity (as evaluated by 6-beta-hydroxycortisol/ cortisol ratio measurement) and the miR-27b plasma concentration: rs = -0.27, p = 0.006. At the same time, correlation analysis revealed a statistically significant relationship between the alprazolam concentration and the miR-27b plasma concentration: rs = 0.28, p = 0.003. CONCLUSION: The effect of genetic polymorphism of the CYP3A4 gene on the efficacy and safety profiles of alprazolam was demonstrated in a group of 105 patients with anxiety disorders comorbid with alcohol use disorder. At the same time, miR-27b remains a promising biomarker for assessing the level of CYP3A4 expression, because it correlates with the encoded isoenzyme's activity.

Effect of smoking and CYP2D6 polymorphisms on the extent of fluvoxamine-alprazolam interaction in patients with psychosomatic disease.

PURPOSE: Fluvoxamine (FVX) is metabolized by cytochrome P450 (CYP) 2D6 and CYP1A2 and inhibits CYP3A4. The aim of this study was to investigate the factors responsible for interindividual variability in the extent of interaction between FVX and alprazolam (ALP). METHODS: Blood samples were taken from 49 depressive patients to determine plasma concentration of FVX, ALP or both. Twenty-four samples were taken during the FVX-alone period, 21 samples during the ALP-alone period and 30 samples during the FVX-ALP period. Subjects were also genotyped for CYP2D6. RESULTS: The concentration-to-dose (C/D) ratio of ALP during the FVX-treatment period was significantly higher than that during the ALP-alone period. The CYP2D6 genotype affected neither the C/D ratios of FVX nor the extent of interaction. The mean C/D ratio of FVX in smokers was reduced by more than 30% in comparison with that in non-smokers. The mean C/D ratio of ALP in non-smokers was increased by FVX, while that in smokers was unchanged. CONCLUSIONS: The extent of interaction between FVX and ALP may be affected by smoking, which alters the C/D ratio of FVX. Therefore, when FVX and ALP are concomitantly administered, it should be noted that non-smokers may exhibit greater drug interaction than smokers.

[Simultaneous determination of 5 sedative hypnotics in human plasma by reversed phase high-performance liquid chromatography].

OBJECTIVE: To determine diazepam, nitrazepam, oxazepam, estazolam, and alprazolam simultaneously in human plasma by reversed phase high-performance liquid chromatography (RP-HPLC). METHODS: Ten microliter carbamazepine (50 mg/L)as the internal standard was added into 1 mL sample, which contained the 5 mixed sedative hypnotics as standard substance and human plasma as ground substance. They were extracted with acetoacetate from plasma samples, and then were dissolved by 100 microL mobile phase. The blood drug levels were analyzed by high performance liquid chromatograph with 20 microL sample injection on a chromatographic column C18 (4.6 mm x 250 mm) at 30 degree. The mobile phase consisted of methanol and water (65:35),and the flow rate was 1.0 mL/min.The ultraviolet detection wavelength was 230 nm. RESULTS: The linearity range of the 5 drugs was 5-1,200 microg/L (r> or =0.9966, P<0.05). The recovery rate was 95.5%-105.6%. The extraction recovery rate was more than 75%. The relative standard deviation (RSD) of intra-day and inter-day was less than 10% (n=5). CONCLUSION: RP-HPLC method is convenient, accurate and sensitive for simultaneous determination of the concentration of diazepam, nitrazepam, oxazepam, estazolam, and alprazolam in human plasma.

Dried blood spots sampling in case samples deprived of hematocrit level information - Investigation and calculation strategy.

The application of a new calculation strategy for the psychotropic drug concentration in blood and bone marrow samples in the form of dried blood spots (DBS) was the main aim of the study. The standard DBS method consists of the deposition of the capillary blood onto the dedicated paper cards. Nowadays, the DBS technique is seen as a fast and partly superior microsampling alternative methodology replacing the conventional venous blood and plasma collection. The calculation approach to drug concentration in the limited volume of the case sample, where the hematocrit level cannot be determined, constitutes an important step of this method. The method has been validated and the results of the determination of alprazolam and diazepam previously spiked in the post-mortem blood and bone marrow sample have been satisfactory.

Pharmacokinetic assessment of alprazolam-induced neonatal abstinence syndrome using physiologically based pharmacokinetic model.

Sustained benzodiazepine use during pregnancy can induce neonatal abstinence syndrome (NAS). In this study, the association between NAS and plasma alprazolam concentration was examined using the measured neonatal concentrations in the time series as well as simulated plasma concentrations of pregnant woman and neonate by physiologically based pharmacokinetic (PBPK) modeling. A neonate born to a mother taking alprazolam daily throughout pregnancy exhibited symptoms such as apnea and vomiting from 9 h to 4 days after birth. Finnegan score was 7 at birth and decreased to 0 by day 4. Apnea improved by 24 h post-delivery and gastrointestinal symptoms disappeared by day 4. The plasma alprazolam concentration in the neonate was 15.2 ng/mL immediately after birth and gradually decreased over 3 days. Measured neonate and estimated maternal plasma alprazolam concentrations were within the 90% prediction intervals of each concentration by PBPK simulation using "pregnancy" and "pediatrics" population parameters including in Simcyp population-based ADME simulator. In conclusion, NAS symptoms such as apnea and digestive events disappeared in parallel with the decrease of the neonate's plasma alprazolam concentrations. Moreover, PBPK modeling and simulation is a useful methodology for toxicological assessment in special characteristics populations lacking specific experimental data.

Cognitive style, alprazolam plasma levels, and treatment response in panic disorder.

This study investigated an anxiety-prone cognitive style (measured by the Anxious Thoughts and Tendencies Questionnaire, AT&T) as a predictor of the acute response to increasing alprazolam plasma levels in panic disorder. Panic disorder patients (n=26) were treated with escalating doses of alprazolam for 4 weeks, then a fixed dose of 1 mg four times a day for 4 weeks. At 0, 1, 2, 3, 4, 6, and 8 weeks, trough alprazolam plasma levels; clinical, self-report, and performance measures; and vital signs were assessed. Panic attack data were from daily diaries. The repeated response measures were analyzed in relation to alprazolam plasma levels using SAS GENMOD, with patients classified as high or low on the baseline AT&T. Panic attacks, anticipatory anxiety, fear, avoidance, overall agoraphobia, the Hamilton Anxiety Rating Scale, and clinicians' global ratings improved with increasing alprazolam plasma levels. Hopkins Symptom Checklist-90 Anger-Hostility; Profile of Mood States Vigor, Confusion, and Friendliness; and speed and accuracy of performance worsened. Patients with high AT&T scores were worse throughout the study on situational panics, fear, avoidance, overall agoraphobia, the Hamilton Anxiety Rating Scale, the Hamilton Rating Scale for Depression, and Clinical Global Improvement; most Hopkins Symptom Checklist-90 clusters; Profile of Mood States Anxiety, Depression, and Confusion; and Continuous Performance Task omissions. We conclude that in panic disorder: (1) alprazolam has a broad spectrum of clinical activity related to plasma levels in individual patients; (2) sedation, disinhibition, and performance deficits may persist for at least a month after dose escalation ends; (3) marked anxiety-prone cognitions predict more symptoms throughout treatment, but do not modify the response to alprazolam and therefore should not influence the choice of alprazolam as treatment.

Cognitive, psychomotor and actual driving performance in healthy volunteers after immediate and extended release formulations of alprazolam 1 mg.

RATIONALE: Alprazolam extended-release (XR) is approved for the treatment of panic disorder. This sustained formulation is absorbed in a delayed manner and is therefore expected to produce fewer and less severe side effects than its immediate release equivalent (alprazolam IR). The effect of alprazolam XR on potentially dangerous daily activities, such as driving a car, is expected to be less as compared to alprazolam IR. OBJECTIVES: The present study was designed to compare the effects of alprazolam XR (1 mg) and alprazolam IR (1 mg) on actual driving ability and cognitive function. METHOD: Eighteen healthy volunteers (aged 20-45 years) participated in a double-blind, placebo-controlled, three-way crossover study. At 4 h post-dose, subjects performed a standardized driving test on a primary highway in normal traffic. Cognitive and psychomotor tests were assessed 1, 2.5, and 5.5 h post-dose. Memory functioning was measured only 1 h after administration. RESULTS: Both formulations severely impaired driving performance between 4 and 5 h after administration. The magnitude of impairment in the driving test observed with alprazolam XR was about half that observed with alprazolam IR. Laboratory test results were in line with the driving data. CONCLUSIONS: The acute impairing effects of alprazolam XR 1 mg on driving and psychomotor functions were generally less, as compared to its immediate-release equivalent, but still of sufficient magnitude to increase the risk of becoming involved in traffic accidents.

Selegiline transdermal system: an examination of the potential for CYP450-dependent pharmacokinetic interactions with 3 psychotropic medications.

Selegiline transdermal system (STS) is a recently approved monoamine oxidase inhibitor antidepressant. This article reports results from 3 studies examining the potential for cytochrome P450-dependent pharmacokinetic interactions between STS and 3 psychotropic medications that might be coadministered. Three open-label, randomized, Latin square, 3-sequence crossover design studies were conducted with healthy volunteers to determine the pharmacokinetic parameters of STS 6 mg/24 h and test drug (alprazolam, olanzapine, or risperidone) when administered alone and concomitantly. All pharmacokinetic parameters of interest were unaltered following selegiline or test drug monotherapy when compared to concomitant therapy. This was confirmed by least squares mean ratios and their 90% confidence intervals of log(e)-transformed C(max) and AUC(tau) values, using either standard bioequivalence criteria of 80% to 125% or study-defined 70% to 143% boundary criteria. These results demonstrate that STS 6 mg/24 h may provide an antidepressant option that is unlikely to result in CYP450-mediated pharmacokinetic drug-drug interactions.

Different acute tolerance development to EEG, psychomotor performance and subjective assessment effects after two intermittent oral doses of alprazolam in healthy volunteers.

BACKGROUND/AIMS: Benzodiazepines (BZDs) are the most effective of the psychotropic drugs in the treatment of anxiety disorders. Tolerance has been reported for the majority of BZDs after chronic administration. However, little attention has been paid to the possibility that tolerance might be present after the intermittent oral administration of BZDs. The objectives of the present study were to assess tolerance development after the administration of two intermittent single oral doses of alprazolam given 15 days apart in healthy volunteers, and to compare the results obtained using measures from different domains: neurophysiological, psychomotor and subjective. METHODS: Twenty-four healthy volunteers received 2 mg of alprazolam orally on two experimental days, 15 days apart. Plasma concentrations and pharmacodynamics (PD) were assessed before drug intake and at different times in the following 24 h. PD was assessed through EEG (relative alpha and relative beta-1 activities), cancellation task (total and correct number of responses) and visual analogue scales (activity and drowsiness). RESULTS: No differences were observed in the PKs of alprazolam between occasions. A proteresis was present in both administrations for impairments of psychomotor performance and relative beta-1 activity, whereas it was present only after the second administration for subjective assessments and relative alpha activity. The proteresis on the second occasion was higher than on the first one. CONCLUSIONS: The administration of two single oral doses of alprazolam, 2 weeks apart in healthy volunteers, yielded the same PKs on both occasions, but significant changes were observed in the PD profile. Acute tolerance was observed after the second administration. Two patterns of acute tolerance development were obtained: (1) impairments of psychomotor performance and relative beta-1 activity, and (2) subjective assessments and relative alpha activity.

Application of Ultrasound-Assisted Surfactant-Enhanced Emulsification Microextraction Based on Solidification of Floating Organic Droplets and High Performance Liquid Chromatography for Preconcentration and Determination of Alprazolam and Chlordiazepoxide in Human Serum Samples.

An improved microextraction method is proposed on the basis of ultrasound-assisted surfactant-enhanced emulsification and solidification of a floating organic droplet procedure combined with high performance liquid chromatography for the preconcentration and quantification of alprazolam (ALP) and chlordiazepoxide (CHL) present in a number of human serum samples. Several parameters affecting the extraction efficiency were investigated by the Plackett -Burman factorial design as the screening design. Then the response surface methodology based on the Box-Behnken design was used to optimize the effective parameters in the proposed procedure. The limits of detection for the proposed method were found to be 3.0 and 3.1 ng mL-1 for CHL and ALP, respectively. The calibration curves obtained for the method were linear in the ranges of 10.0-3,500.0 and 10.0-3,000.0 ng mL-1 for CHL and ALP, respectively, with a good determination coefficient. The recoveries of the drugs in the spiked human serum samples were above 93.0%. The developed method was successfully applied to the analysis of these studied drugs in human serum samples. The pre-treatment of the serum samples was performed using acetonitrile to remove the proteins. The proposed procedure was an accurate and reliable one for the determination and preconcentration of these drugs in blood samples.