The bioavailability of bromazepam, omeprazole and paracetamol given by nasogastric feeding tube.

AIMS: To characterize and compare the pharmacokinetic profiles of bromazepam, omeprazole and paracetamol when administered by the oral and nasogastric routes to the same healthy cohort of volunteers. METHODS: In a prospective, monocentric, randomized crossover study, eight healthy volunteers received the three drugs by the oral (OR) and nasogastric routes (NT). Sequential plasma samples were analyzed by high-performance liquid chromatography-UV, pharmacokinetic parameters (Cmax, AUC(0-infinity), t(1/2), k(e), tmax) were compared statistically, and Cmax, AUC(0-infinity) and t(max) were analyzed for bioequivalence. RESULTS: A statistically significant difference was seen in the AUC(0-infinity) of bromazepam, with nasogastric administration decreasing availability by about 25%: AUC(OR) = 2501 ng mL(-1) h; AUC(NT) = 1855 ng mL(-1) h (p < 0.05); ratio (geometric mean) = 0.74 [90% confidence interval (CI) 0.64-0.87]. However, this does not appear to be clinically relevant given the usual dosage range and the drug's half-life (approx. 30 h). A large interindividual variability in omeprazole parameters prevented any statistical conclusion from being drawn in terms of both modes of administration despite their similar average profile: AUC(OR) = 579 ng mL(-1) h; AUC(NT) = 587 ng mL(-1) h (p > 0.05); ratio (geometric mean) = 1.01 (90% CI 0.64-1.61). An extended study with a larger number of subjects may possibly provide clearer answers. The narrow 90% confidence limits of paracetamol indicate bioequivalence: AUC(OR) = 37 microg mL(-1) h; AUC(NT) = 41 microg mL(-1) h(p > 0.05); ratio (geometric mean) = 1.12 (90% CI 0.98-1.28). CONCLUSION: The results of this study show that the nasogastric route of administration does not appear to cause marked, clinically unsuitable alterations in the bioavailability of the tested drugs.

Cardiac and peripheral blood similarities in the comparison of nordiazepam and bromazepam blood concentrations.

Concomitant heart and peripheral blood determinations were performed on 40 fatal cases involving nordiazepam (20 cases) and bromazepam (20 cases). The heart blood concentration for the two drugs (588 ng/mL for nordiazepam and 802 ng/mL for bromazepam) does not differ from the corresponding peripheral blood concentration (587 ng/mL for nordiazepam and 883 ng/mL for bromazepam). The mean ratios for the heart and peripheral blood concentrations were 0.95 for nordiazepam and 0.86 for bromazepam. No postmortem redistribution was observed for these two benzodiazepines. The authors thus suggest that corresponding heart blood can be proposed in the quantitative analysis of these drugs when peripheral blood is unavailable. The present study also shows the stability of the two drugs after a year of storage.

Blood levels and electroencephalographic effects of diazepam and bromazepam.

Blood levels and electroencephalographic (EEG) data were collected for 2 hr after single oral doses of bromazepam (9 mg), diazepam (10 mg), and placebo in 13 male adult volunteers. Both drugs caused an increase in beta activity (above 13 Hz) and a decrease in alpha activity (9 to 11 Hz) in the EEG. Blood levels of 100 ng/ml of diazepam or 50 ng/ml of bromazepam were associated with significant changes in EEG beta activity. Temporal changes in the EEG after administration of diazepam or bromazepam paralleled development of plasma levels of these drugs. Although a weakly significant correlation was found between measurable diazepam blood levels and amount of increased EEG beta activity, the relationship between measurable bromazepam blood levels and the degree of EEG changes was not significant. Quantitative EEG is a sensitive continuous response measure, useful in defining cerebral activity, response latency, and relative potency of psychoactive benzodiazepines.

Bromazepam pharmacokinetics: influence of age, gender, oral contraceptives, cimetidine, and propranolol.

Pharmacokinetics of the benzodiazepine bromazepam were evaluated in volunteer subjects who received single 6 mg oral doses followed by blood sampling during the next 48 hours. Age and gender effects were studied in 32 subjects, divided into young (aged 21 to 29 years) and elderly (aged 60 to 81 years) groups. Compared with young subjects, the elderly had significantly higher peak serum bromazepam concentrations (132 vs. 82 ng/ml), smaller volume of distribution (0.88 vs. 1.44 L/kg), lower oral clearance (0.41 vs. 0.76 ml/min/kg), and increased serum free fraction (34.8% vs. 28.8% unbound). However, gender had no significant influence on bromazepam kinetics. In 11 young female users of oral contraceptive steroids, compared with seven age- and weight-matched control women not using oral contraceptives, no differences in bromazepam kinetics were observed. Coadministration of cimetidine (1.2 gm daily) significantly reduced bromazepam clearance (0.41 vs. 0.82 ml/min/kg) and prolonged elimination half-life (29 vs. 23 hours). Propranolol (160 mg daily) significantly prolonged bromazepam half-life (28 vs. 23 hours), but the reduction in clearance associated with propranolol (0.65 vs. 0.82 ml/min/kg) did not reach significance. Bromazepam has the pharmacokinetic characteristics of benzodiazepines with half-life values between 20 and 30 hours. Consistent with its biotransformation pathway by hepatic microsomal oxidation, bromazepam clearance is significantly impaired in elderly individuals, by coadministration of cimetidine and possibly propranolol.

Bromazepam determination in human plasma by high-performance liquid chromatography coupled to tandem mass spectrometry: a highly sensitive and specific tool for bioequivalence studies.

A rapid, sensitive and specific method to quantify bromazepam in human plasma using diazepam as the internal standard (IS) is described. The analyte and the IS were extracted from plasma by liquid-liquid extraction using diethyl ether-hexane (80 : 20, v/v). The extracts were analyzed by high-performance liquid chromatography (HPLC) coupled to electrospray tandem mass spectrometry (MS/MS). Chromatography was performed isocratically on a Genesis C(18) analytical column (100 x 2.1 mm i.d., film thickness 4 microm). The method had a chromatographic run time of 5.0 min and a linear calibration curve over the range 5.0-150 ng ml(-1) (r(2) > 0.9952). The limit of quantification was 5 ng ml(-1). This HPLC/MS/MS procedure was used to assess the bioequivalence of two bromazepam 6 mg tablet formulations (bromazepam from Medley SA Indústria Farmacêutica as the test formulation and Lexotan from Produtos Roche Químico e Farmacêutico SA as the reference formulation). A single 6 mg dose of each formulation was administered to 24 healthy volunteers (12 males and 12 females). The study was conducted using an open, randomized, two-period crossover design with a 3 week washout interval. Since the 90% CI for C(max), AUC(last), AUC(0-240 h) (linear) and AUC((0- infinity )) ratios were all inside the 80-125% interval proposed by the US Food and Drug Administration, it was concluded that the bromazepam formulation from Medley is bioequivalent to the Lexotan formulation for both the rate and the extent of absorption.

Determination of bromazepam in human plasma by high-performance liquid chromatography with electrospray ionization tandem mass spectrometric detection: application to a bioequivalence study.

A simple method using a one-step liquid-liquid extraction (LLE) followed by high-performance liquid chromatography (HPLC) with positive ion electrospray ionization tandem mass spectrometric (ESI-MS/MS) detection was developed for the determination of bromazepam in human plasma, using lorazepam as internal standard. The acquisition was performed in the multiple reaction monitoring mode, monitoring the transitions: m/z 316 > 182 for bromazepam and m/z 321 > 275 for lorazepam. The method was linear over the studied range (1-100 ng ml(-1)), with r(2) > 0.98, and the run time was 2.5 min. The intra- and inter-assay precisions were 2.7-14.6 and 4.1-17.3%, respectively and the intra- and inter-assay accuracies were 87-111 and 75.8-109.5%, respectively. The mean recovery was 73.7%, ranging from 64.5 to 79.7%. The limit of quantification was 1 ng ml(-1). At this concentration the mean intra- and inter-assay precisions were 14.6 and 7.1%, respectively, and the mean intra- and inter-assay accuracies were 102.5 and 104%, respectively. Bromazepam stability was evaluated and the results showed that the drug is stable in standard solution and in plasma samples under typical storage and processing conditions. The method was applied to a bioequivalence study in which 27 healthy adult volunteers (14 men) received single oral doses (6 mg) of reference and test bromazepam formulations, in an open, two-period, randomized, crossover protocol. The 90% confidence interval of the individual ratios (test formulation/reference formulation) for C(max) (peak plasma concentration), AUC(0-96) and AUC(0-inf) (area under the plasma concentration versus time curve from time zero to 96 h and to infinity, respectively) were within the range 80-125%, which supports the conclusion that the test formulation is bioequivalent to the reference formulation regarding the rate and extent of bromazepam absorption.

The determination of bromazepam in plasma by reversed-phase high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic method has been developed for the determination of bromazepam, an anxiolytic benzodiazepine, in plasma. After a single-step extraction from alkalinized plasma with diethyl-ether in the presence of an internal standard (alpha-hydroxy-triazolam), the residues were chromatographed on a reversed-phase Nova Pak 5 microns C18 column, with a mobile phase of acetonitrile-water-triethylamine (700:300:4, v/v/v) adjusted to pH 7.4 with orthophosphoric acid. The limit of detection was 50 ng ml-1, using a 20 microliters injection with UV detection at 240 nm. Between-day and within-day relative standard deviations were lower than 6%. Studies of drug stability during sample storage at -20 degrees C and at +4 degrees C showed no degradation of bromazepam. However, bromazepam seemed to be degraded at ambient temperature, without any influence of light. This method is applied to the determination of bromazepam plasma levels in analytical toxicology.

Quantitation using GC-TOF-MS: example of bromazepam.

Time-of-flight mass spectrometry (TOF-MS) offers new perspectives for forensic toxicology. Qualitative and quantitative analyses of a mixture of three selected benzodiazepines (diazepam, nordazepam and bromazepam) were used to compare gas chromatography (GC-TOF-MS, quadrupole GC-MS, GC-ECD) and liquid chromatography (HPLC-DAD) data. Method validation parameters like LOD, LOQ, S/N-ratios reflect the capabilities of GC-TOF-MS. Five-point calibrations for bromazepam in human peripheral blood (50, 100, 160, 200, 300 ng/ml) using medazepam as internal standard (1000 ng/ml) were performed. The calibrations using GC-TOF-MS (using the fragments of m/z 236 and 288), GC-ECD (dual system) and HPLC-DAD (at 235 nm) all showed correlation coefficients close or superior to 0.99. Quadrupole GC-MS data was not used in the comparison of extracted samples due to the low sensitivity in the full scan mode. Two analyses of real cases concerning bromazepam are presented. In the first case, the presence or absence of bromazepam could not be established with both HPLC-DAD and GC-ECD due to background signals. The extracted ion chromatograms and spectrum traces after the analysis with the GC-TOF-MS could clearly excluded the presence of bromazepam. The second case illustrates the quantitation of bromazepam, where both HPLC-DAD and GC-ECD were unable to give satisfactory results, again due to interfering background signals. The analyses performed on the GC-TOF-MS-system demonstrated high sensitivity and also high selectivity due to the high quality of mass spectra obtained. The advantages of GC-TOF-MS make it a promising analytical technique for forensic toxicology.

Death attributed to the toxic interaction of triazolam, amitriptyline and other psychotropic drugs.

A 71-year-old man was found dead in a car into which exhaust fumes had been introduced. His wife who was in the same car recovered consciousness following hospitalization. She claimed that they had both attempted suicide by taking a large number of sleeping pills. Autopsy revealed no significant external injuries or medical disorders that would have led to the husband's death. The concentrations of alcohol and carbon-monoxide hemoglobin in his whole blood were 0.26 mg/ml and < 10%, respectively. Therefore, poisoning by carbon monoxide from the exhaust fumes was ruled out, and further toxicological examinations were undertaken. Triazolam, pentobarbital, amitriptyline and bromazepam were all detected in the tissues of the victim; whole blood concentrations were 45.60, 386.4, 521.2 and 166.7 ng/g, respectively. Triazolam (7.350 ng/g) and pentobarbital (288.2 ng/g) were also detected in the whole blood of the wife, collected 17 h after admission to hospital. When evaluating these results in the light of existing literature, we concluded that the victim and his wife had indeed attempted suicide by taking triazolam and pentobarbital. However, only the man had died of triazolam poisoning due to its apparently lethal combination with amitriptyline and other psychotropic drugs which had been prescribed to treat his depression.

LC/MS determination of bromazepam, clopenthixol, and reserpine in serum of a non-fatal case of intoxication.

Combined liquid chromatography and mass spectrometry (LC/MS) with a moving belt interface can be used as a rapid method for the determination of bromazepam, clopenthixol, and reserpine in serum samples obtained from cases of acute overdoses with combinations of these drugs. Low resolution detection limits are about 100 pg for the three drugs, while in high resolution mode the detection limit for bromazepam is shown to be at least 35 pg. Accurate masses were obtained in a serum sample within 5 ppm using high voltage scanning over a narrow mass range for about 10 ng of bromazepam and clopenthixol, respectively. Chemical deactivation of the belt was shown to effectively reduce memory effects and to improve the desorption characteristics of the belt leading to higher yields of evaporated intact molecules.

Benzodiazepines: toxic serum concentrations in positive enzyme immunoassay responses.

A total of 588 blood specimens collected in an emergency unit were screened for benzodiazepines (BZDs) using enzyme-multiplied immunoassay and gas chromatography. Two-hundred eighty-five samples were positive for BZDs, and 303 samples that were negative by EMIT included 20 samples with BZDs detectable by gas-liquid chromatography. A total of 15 BZDs were identified, and the most frequently occurring were nordiazepam, bromazepam, diazepam, and alprazolam. Individual BZDs were found in 74% of cases, but some samples contained two, three, or even four BZDs. There is a risk of missing intoxication by BZDs with low therapeutic range and/or low cross-reactivity (alprazolam, bromazepam, flunitrazepam). There is a risk of misinterpreting a positive result for some BZDs with high therapeutic range and/or high cross-reactivity (nordiazepam), which may reflect a pharmacologically ineffective concentration. A semiquantitative analysis is inappropriate even when the identity of BZD is known. Immunoassays are the only methods presently available for use in emergencies, but physicians must be clearly informed of their limitations and interpret results with caution.

Difficulties in assessing brain death in a case of benzodiazepine poisoning with persistent cerebral blood flow.

Assessing brain death may sometimes be difficult, with isoelectric EEG following psychotrope overdoses or normal cerebral blood flow (CBF) persisting despite brain death in the case of ventricular drainage or craniotomy. A 42-year-old man, resuscitated after cardiac arrest following a suicidal ingestion of ethanol, bromazepam and zopiclone, was admitted in deep coma. On day 4, his brainstem reflexes and EEG activity disappeared. On day 5, his serum bromazepam concentration was 817 ng/ml (therapeutic: 80-150). The patient was unresponsive to 1 mg of flumazenil. MRI showed diffuse cerebral swelling. CBF assessed by angiography and Doppler remained normal and EEG isoelectric until he died on day 8 with multiorgan failure. There was a discrepancy between the clinically and EEG-assessed brain death, and CBF persistence. We hypothesized that brain death, resulting from diffuse anoxic injury, may lead, in the absence of major intracranial hypertension, to angiographic misdiagnoses. Therefore, EEG remains useful to assess diagnosis in such unusual cases.

Spectrofluorimetric quantification of bromazepam using a highly selective optical probe based on Eu3+-bromazepam complex in pharmaceutical and serum samples.

A rapid, simple and sensitive spectrofluorimetric method for determination of trace amount of bromazepam is developed. In phosphate buffer of pH 7.4. The bromazepam enhance the luminescence intensity of the Eu(3+) ion in Eu(3+)-bromazepam complex at lambda(ex)=390nm. The produced luminescence intensity of Eu(3+)-bromazepam complex is in proportion to the concentration of bromazepam. The working range for the determination of bromazepam is 2.3x10(-8) to 6.2x10(-7)M with detection limit (LoD) and quantitative detection limit (LoQ) of 3x10(-9) and 1.2x10(-8)M, respectively. While, the working range, detection limit (LoD) and quantitative detection limit (LoQ) in case of the quantum yield calculations are 3.7x10(-8) to 3.4x10(-7)M with of 3.4x10(-9) and 9.2x10(-8)M, respectively. The enhancement mechanism of the luminescence intensity in the Eu(3+)-bromazepam system has been also explained.

On-line solid-phase extraction coupled with high-performance liquid chromatography and tandem mass spectrometry (SPE-HPLC-MS-MS) for quantification of bromazepam in human plasma: an automated method for bioequivalence studies.

A validated method for on-line solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry (SPE-HPLC-MS-MS) is described for the quantification of bromazepam in human plasma. The method involves a dilution of 300 muL of plasma with 100 muL of carbamazepine (2.5 ng/mL), used as internal standard, vortex-mixing, centrifugation, and injection of 100 muL of the supernate. The analytes were ionized using positive electrospray mass spectrometry then detected by multiple reaction monitoring (MRM). The m/z transitions 316-->182 (bromazepam) and 237-->194 (carbamazepine) were used for quantification. The calibration curve was linear from 1 ng/mL (limit of quantification) to 200 ng/mL. The retention times of bromazepam and carbamazepine were 2.6 and 3.2 minutes, respectively. The intraday and interday precisions were 3.43%-15.45% and 5.2%-17%, respectively. The intraday and interday accuracy was 94.00%-103.94%. This new automated method has been successfully applied in a bioequivalence study of 2 tablet formulations of 6 mg bromazepam: Lexotan(R) from Produtos Roche Químicos e Farmacêuticos SA, Rio de Janeiro, Brazil (reference) and test formulation from Laboratórios Biosintética Ltda, São Paulo, Brazil. Because the 90% CI of geometric mean ratios between reference and test were completely included in the 80%-125% interval, the 2 formulations were considered bioequivalent. The comparison of different experimental conditions for establishing a dissolution profile in vitro along with our bioavailability data further allowed us to propose rationally based experimental conditions for a dissolution test of bromazepam tablets, actually lacking a pharmacopeial monograph.

Determination of bromazepam in plasma with an internal standard by gas-liquid chromatography.

A gaschromatographic assay method is described for the determination of Ro 5-3350 (bromazepam) using Ro 5-4547 (methylbromazepam) as internal standard. After alkaline ether extraction the bromazepam and methylbromazepam obtained from sulfuric acid reextraction are hydrolyzed to ABBP and to MABBP, respectively. After neutralization, the bromo-pyridine-benzophenones are extracted with ether and dissolved in hexane after evaporation of the ether. Under the described gaschromatographic conditions it was found that MABBP and ABBP have retention times of 10.5 and 12.5 min, respectively. The limit of sensitivity is situated at 5 ng/ml of plasma. The specificity is satisfactory since the metabolite which might have interfered (hydroxy-3-bromazepam) appears only at very low concentrations in the blood. The linearity of the calibration curve was confirmed for plasma concentrations up to 100 ng/ml.

Effect of food on the bioavailability of bromazepam following oral administration in healthy volunteers.

The effect of food on the rate and extent of bioavailability of bromazepam was examined in seven normal volunteers following a single oral dose of 10 mg bromazepam with 200 ml of water in the fasting and non-fasting states. Plasma concentrations of bromazepam were measured by high pressure liquid chromatography. A tmax value in a non-fasting state was prolonged from 2.3 +/- 0.3 (mean +/- S.E.M.) to 2.8 +/- 0.6 h but not significantly different (p greater than 0.05) whereas a Cmax value was significantly (p less than 0.05) decreased from 259 +/- 12.7 (mean +/- S.E.M.) to 169 +/- 13.9 ng/ml. The area under the plasma concentration-time curve in the non-fasting state was also significantly (p less than 0.05) decreased from 1844 +/- 145 (mean +/- S.E.M.) to 1233 +/- 98.1 ng.h/ml after oral administration of bromazepam.

High-performance liquid chromatographic determination of bromazepam in human plasma.

An assay using high-performance liquid chromatography has been developed for the determination of bromazepam in plasma. After a single-step extraction from basified samples with dichloromethane, using decarboxyloflazepate as an internal standard, samples were analysed using a reversed-phase Nova Pak 5-microns column with a mobile phase of methanol - phosphate buffer (60 + 40) adjusted to pH 7.6. The drugs were detected at 239 nm and the limit of detection was found to be 3 micrograms l-1 for bromazepam. The method is simple, rapid and sensitive and permits bromazepam levels in clinical and pharmacokinetic studies to be monitored.

The effect of bromazepam (Lexotan) administration on antipyrine pharmacokinetics in humans.

Six healthy volunteers were given a standard regimen of bromazepam (Lexotan) (6 mg t.d.s.) for five days. Compliance with the study protocol was demonstrated by measuring drug concentrations at steady state. Steady-state levels of 3-hydroxybromazepam were also determined. These were found to be much lower than the concentrations of bromazepam. Since the metabolite is known to be less active than the parent drug, it is likely that the metabolic will contribute little to the pharmacological effects of the drug in humans. Antipyrine pharmacokinetics were studied immediately before bromazepam administration was started, after the dosing schedule had been completed and one week after dosing had been discontinued. There were no significant changes in the disposition of antipyrine on any occasion. Therefore, although previous studies have demonstrated enzyme induction in laboratory animals given high doses of bromazepam, similar effects are unlikely to occur in humans being treated with therapeutic doses of the compound.

Blood levels and the quantitative EEG response to CNS-active drugs: retrospective observations.

Quantitative EEG measures provide reliable, non-invasive indices of CNS effects of drugs in man. In pharmaco-EEG studies of CNS-active substances, we found that EEG changes correlated with blood drug levels within individuals over time, and showed the correlation to be replicable. Across individuals at single times, however, correlations were not evident. In seeking relationships across subjects, techniques which adjust for EEG baseline differences between subjects are under investigation.

Bromazepam and diazepam in generalized anxiety: a placebo-controlled study with measurement of drug plasma concentrations.

In a double-blind, placebo-controlled study, 48 anxious outpatients with a primary diagnosis of generalized anxiety disorder were randomly assigned to 4 weeks of treatment with bromazepam (18 mg/day), diazepam (15 mg/day), or placebo, after a 1-week washout period. From week 1 onward both active drugs were superior to placebo in relieving anxiety symptoms. Bromazepam was found to be significantly more effective than diazepam with respect to the somatic anxiety factor and the total score for the Hamilton Anxiety Rating Scale and the fear/anxiety factor of the Patient's Self-Rating Symptom Scale. Plasma concentrations of diazepam plus active metabolites were correlated significantly (r = 0.60, p less than 0.05) with the percentage reduction in self-rating anxiety scores. Bromazepam plasma concentration measurements showed greater variability than those of diazepam and were not found to be correlated significantly with clinical response. It is suggested that the use of strict diagnostic criteria (1978 draft of the third edition of Diagnostic and Statistical Manual of Mental Disorders), adequate sample sizes, and a 4-week study period gave increased sensitivity for the detection of significant differences between the two benzodiazepines.