[Determination of 10 sedative-hypnotics in human plasma using pulse splitless injection technique and gas chromatography-mass spectrometry].

A simple, precise and sensitive gas chromatography-mass spectrometry (GC-MS) method coupled with pulse splitless injection technique was developed for the determination of 10 sedative-hypnotics (barbital, amobarbital, phenobarbital, oxazepam, diazepam, nitrazepam, clonazepam, estazolam, alprazolam, triazolam) in human plasma. The drugs spiked in plasma were extracted with ethyl acetate after alkalization with 0.1 mol/L NaOH solution. The organic solvent was evaporated under nitrogen stream, and the residues were redissolved by ethyl acetate. The separation was performed on an HP-5MS column (30 m x 250 microm x 0.25 microm). The analytes were determined and identified using selected ion monitoring (SIM) mode and scan mode, respectively. The internal standard method was used for the determination. The target analytes were well separated from each other on their SIM chromatograms and also on the total ion current (TIC) chromatograms. The blank extract from human plasma gave no peaks that interfered with all the analytes on the chromatogram. The calibration curves for 10 sedative-hypnotics showed excellent linearity. The correlation coefficients of all the drugs were higher than 0.9954. The recoveries of the drugs spiked in human plasma ranged from 92.28% to 111.7%, and the relative standard deviations (RSDs) of intra-day and inter-day determinations were from 4.09% to 14.26%. The detection limits ranged from 2 to 20 microg/L. The method is simple, reliable, rapid and sensitive for the determination and the quantification of 10 sedative-hypnotics in human plasma and seems to be useful in the practice of clinical toxicological cases.

[The influence of estazolam on human neurobehavioral function].

OBJECTIVE: To study the relation between human blood estazolam concentration and neurobehavioral function. METHODS: The neurobehavioral ability of 10 volunteers were measured with computer-administered neurobehavioral evaluation system-chinese3 (NES-C3) and SMART EquiTest system. RESULTS: The neurobehavioral ability and balance function declined 1 h later after dosing estazolam. The neurobehavioral ability index and balance function declined to the lowest level 3 h later after dosing estazolam. The neurobehavioral ability recovered partly 6 h later after dosing estazolam, and neurobehavioral ability recovered completely 10 h later. CONCLUSION: Driving ability was impaired when estazolam concentration in blood is 20 ng/mL, and the neurobehavioral ability declined when estazolam concentration is 40 ng/mL in blood. The influence to human in absorption process is greater than the metabolic process with the same estazolam concentration.

[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.

[Analysis of 37 drugs in whole blood by HPLC after solid phase extraction].

OBJECTIVE: To develop a specific, sensitive, reproducible SPE-HPLC method for the determination of 37 drugs in whole blood. METHODS: With the doxapram as internal standard, Oasis column was used to extract drugs from whole blood. Two kinds of mobile phases were used in this study. Separations were achieved by a LiChrospher 100 RP-C18 (250 mm x 4.0 mm x 5 microm) column kept at 50 degrees C, the DAD detector was set at 230 nm and 250 nm. RESULTS: The limit of detection were 1-30 ng/mL. The method showed excellent linearity and the linear correlation coefficient was > or =0.997 98. The relative standard deviation for between-day and within-day assay were <10%. CONCLUSION: The method is effective, simple, reliable and has been used in real cases.

Effects of the CYP2C19 genotype and cigarette smoking on the single oral dose pharmacokinetics and pharmacodynamics of estazolam.

The effects of the cytochrome P450 (CYP)2C19 genotype and cigarette smoking on the single oral dose pharmacokinetics and pharmacodynamics of estazolam were studied in 16 healthy male volunteers. The two mutated alleles (CYP2C19*2 and CYP2C19*3) causing absent CYP2C19 activity were identified by PCR-based restriction enzyme analysis. Five subjects had no mutated allele, five had one mutated allele, and six had two mutated alleles. Seven subjects were smokers, and nine were nonsmokers. The subjects received a single oral 4-mg dose of estazolam, and blood samplings and evaluation of psychomotor function were conducted up to 72 h after dosing. There was no significant difference among the groups with no, one, and two mutated alleles for the peak plasma concentration (145.2+/-36.5 vs. 142.1+/-33.6 vs. 113.2+/-29.7 ng/ml), area under the plasma concentration-time curve (0- infinity ) (4916.0+/-1276.4 vs. 4389.6+/-736.1 vs. 4047.3+/-613.8 ng x h/ml), apparent oral clearance (0.22+/-0.05 vs. 0.25+/-0.03 vs. 0.25+/-0.03 ml/min/kg), and elimination half-life (24.4+/-4.6 vs. 29.6+/-8.5 vs. 30.7+/-3.9 h). Similarly, none of the pharmacokinetic parameters was significantly different between the nonsmoker and smoker groups. Neither the number of mutated allele nor cigarette smoking affected the psychomotor function parameters significantly. The present study suggests that neither the CYP2C19 genotype nor cigarette smoking affects the single oral dose pharmacokinetics and pharmacodynamics of estazolam.

Determination of hypnotic benzodiazepines (alprazolam, estazolam, and midazolam) and their metabolites in rat hair and plasma by reversed-phase liquid-chromatography with electrospray ionization mass spectrometry.

Sensitive determination of benzodiazepines i.e., alprazolam (ALP), estazolam (EST), and midazolam (MDZ), and their metabolites, was carried out by reversed-phase liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI-MS). The chromatography separations were achieved using a semi-micro HPLC column (3 microm particle size; 100 x 2.0 mm, i.d.) with acetonitrile-water containing 1% acetic acid as eluent. The mass spectrometer was operated in selected-ion monitoring mode at protonated-molecular ions [M+H](+) of parent drugs and the metabolites. The proposed procedure was applied to the determination in hair shaft of Dark Agouti rats after intraperitoneal (i.p.) administration of benzodiazepines twice a day for 5 days. Various metabolites together with parent drugs were identified in the hair shaft, 1-hydroxyalprazolam (1-HA) and 4-hydroxyalprazolam (4-HA) from ALP administration; 8-chloro-6-phenyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine-4-one (K-EST) from EST administration; 1-hydroxymidazolam (1-HM) and 4-hydroxymidazolam (4-HM) from MDZ administration. A few unknown metabolites were also detected in the hair samples. These structures were elucidated with acetylation using acetic anhydride and pyridine. The time course studies of parent drugs and the metabolites in both hair root and plasma were also carried out after single i.p. administration of benzodiazepines. The results suggested that the concentrations of parent drugs and the metabolites in the hair samples were mainly dependent upon those in the plasma.

Determination of estazolam in plasma by high-performance liquid chromatography with solid-phase extraction.

A high-performance liquid chromatography (HPLC) assay was developed for the determination of estazolam in human plasma. Estazolam and alprazolam as an internal standard were detected by ultraviolet absorbance at 240 nm. Estazolam in plasma was extracted by a rapid and simple procedure based on cyanopropyl bonded-phase extraction. Chromatographic separation was achieved with a reversed-phase C8-5 column using a mobile phase of 0.5% potassium dihydrogenphosphate(pH 4.5)-acetonitrile (70:30, v/v). The determination of estazolam was possible in the concentration range of 1.0 - 200.0 ng/mL. The mean recovery of estazolam added to plasma was 96.1 +/- 1.5% with coefficients of variation of less than 5.5%. This method is applicable for accurately monitoring the plasma level of estazolam in healthy subjects participating in scientific research.

No effect of itraconazole on the single oral dose pharmacokinetics and pharmacodynamics of estazolam.

To examine the involvement of cytochrome P450 3A4 in the metabolism of estazolam, the effect of itraconazole, a potent inhibitor of this enzyme, on the single oral dose pharmacokinetics and pharmacodynamics of estazolam was studied in a double-blind randomized crossover manner. Ten healthy male volunteers received itraconazole 100 mg/day or placebo orally for 7 days, and on the 4th day they received a single oral 4-mg dose of estazolam. Blood samplings and evaluation of psychomotor function by the Digit Symbol Substitution Test, Visual Analog Scale, and Stanford Sleepiness Scale were conducted up to 72 hours after estazolam dosing. There was no significant difference between the placebo and itraconazole phases for the peak plasma concentration, apparent oral clearance, and elimination half-life. Similarly, none of the psychomotor function parameters was significantly different between the two phases. The current study showed no significant effect of itraconazole on the single oral dose pharmacokinetics and pharmacodynamics of estazolam, suggesting that cytochrome P450 3A4 is not involved in the metabolism of estazolam to a major extent.

[Two complex suicidal poisonings with drugs and their medicolegal aspects]. / Dwa kompleksowe samobójcze zatrucia lekami w aspekcie orzecznictwa sadowo-lekarskiego.

The main subject of the study was a toxicological investigation of biological specimens coming from two cases of intoxication with mixture of drugs. Two young people decided to commit suicide by the use of mixture of drugs mainly analgesic in approximately equal doses. For one person the dose of drugs administered turned out to be fatal while second person survived with the symptoms of acute intoxication. The analysis carried out with the use of liquid chromatographic method with mass detection (HPLC/MS) confirmed the presence of mixture of drugs in blood of living person and in postmortem specimens of the victim in significant concentrations. The toxicological findings have delivered information for discussion in medico-legal and ethical aspects.

Screening and determination of benzodiazepines in whole blood using solid-phase extraction and gas chromatography/mass spectrometry.

Benzodiazepines are one of the most widely prescribed drugs for the treatment of a wide spectrum of clinical disorders. They are used as anticonvulsants, anxiolytics, hypnotics or muscle relaxants with different duration of action. In this paper, a simple and sensitive method for the determination of benzodiazepines in whole blood using solid-phase extraction and gas chromatography/mass spectrometry (GC/MS) is described. The drugs spiked in whole blood were extracted with an Oasis HLB solid-phase extraction cartridge (Waters), which contains a copolymer designed to have a hydrophilic-lipophilic balance. GC/MS analysis was performed using a Shimadzu QP-5000 equipped with a BPX5 capillary column (15 mx0.32 mm I.D., film thickness 0.25 microm, SGE). Nineteen benzodiazepines and two thienodiazepines were well separated from each other on their SIM chromatograms and also on the TIC with the exception of oxazolam to cloxazolam separation. The blank extract from whole blood gave no peaks that interfered with all benzodiazepines and thienodiazepines on the chromatogram. The calibration curves for selected benzodiazepines with fludiazepam as an internal standard showed excellent linearity over the concentration range 5-500 ng/ml blood with a correlation coefficients of >0.995. The detection limits ranged from 0.2 to 20 ng/ml blood. The method is simple and sensitive for the determination of benzodiazepines in whole blood and seems to be useful in the practice of forensic science.

Sexual assault under benzodiazepine submission in a Paris suburb.

Sexual assaults under benzodiazepine submission have been described, since use of benzodiazepine enables non consensual sexual activity but rarely fully reported. An accurate evaluation of the phenomenon has seemed interesting. Files of 23 adult males and females examined at the Emergency Forensic Unit of an University Teaching Hospital near Paris were reviewed. All the victims had complained from sexual assault under drug submission, in the years 1996 and 1997. A complete examination for sexual assault was realised linked to clinical examination of drug intoxication. Every victim of rape under drug submission was sampled for urine screening (mean delay of 17.5 h after sexual assault) and blood alcohol level quantification. Urine was screened for benzodiazepines, cocaine, opiates and cannabinoids with qualitative immunochromatographic test. Traumatic lesions of sexual penetration were retrieved in 10 victims and sperm in 5. Clinical signs of benzodiazepine intoxication were retrieved in 12 out of 23 victims. Urine benzodiazepine screening was positive, over the cut-off values (300 ng/mL)when sampled less than 20 h after the facts. In 6 out of 23 victims, drugs of abuse and alcohol were associated to benzodiazepines. A reinforced attention can be brought to the rape under drug submission including the need of a proper examination and samplings shortly after the alleged facts to ascertain the diagnosis and to help the victim facing the Justice inquiry.

Gas chromatographic assay for estazolam in human plasma and results of a bioequivalence study.

This paper describes a new sensitive gas chromatographic method with electron capture detector to assay estazolam in human plasma, which has been developed and validated for pharmacokinetic purposes. The drug and the internal standard (triazolam) were extracted from plasma buffered at pH 9.0 into toluene and analysed on a widebore DB 17 column. The calibration curve covered the 1.0-200 ng ml-1 range with a mean determination coefficient of 0.9996. The quantification limit was 1.0 ng ml-1. This method was used to investigate the bioequivalence of a new formulation of estazolam in drops (test) and the formulation in tablets (reference, ESILGAN). Both formulations were administered at a single dose of 2 mg in a clinical trial carried out on 24 healthy volunteers consisting of 12 males and 12 females, following a crossover randomised design in two periods with wash-out. The test and the reference formulations proved to be fully bioequivalent according to operating guidelines, namely through 90% confidence intervals in the 0.80-1.25 range.

Simultaneous determination of twelve benzodiazepines in human serum using a new reversed-phase chromatographic column on a 2-microns porous microspherical silica gel.

A high-performance liquid chromatographic method has been developed for the simultaneous analysis of twelve frequently used benzodiazepines (BZPs) (bromazepam, clonazepam, chlordiazepoxide, estazolam, etizolam, flutazoram, haloxazolam, lorazepam, nitrazepam, oxazolam, triazolam and diazepam, internal standard) by using commercially available 2 or 5 microns particle size reversed-phase columns and a microflow cell-equipped ultraviolet detector. The separation was achieved using a C18 reversed-phase column (condition 1: 100 x 4.6 mm I.D., particle size 2 microns, TSK gel Super-ODS: conditon 2: 100 x 4.6 mm I.D., particle size 5 microns, Hypersil ODS-C18). The mobile phase was composed of methanol-5 mM NaH2PO4 (pH 6) (45:55, v/v), and the flow-rate was 0.65 ml/min (condition 1 and 2). The absorbance of the eluent was monitored at 254 nm. Retention times under condition 1 were shorter than those of condition 2. When the twelve benzodiazepines were determined, sensitivity and limits of quantification were about four to ten times better under condition 1 than under condition 2. The rate of recovery and linearity in condition 1 were approximately the same as those in condition 2. These results show that a new ODS filler with a particle size of 2 microns was more sensitive, provided better separation and was more rapid than that with conventional ODS filler.

Application of capillary electrophoresis to the simultaneous screening and quantitation of benzodiazepines.

Capillary electrophoresis (CE) is an attractive approach for the analysis of drugs in body fluids. We made a simultaneous analysis of nitrazepam, diazepam, estazolam, bromazepam, triazolam and flurazepam using CE with on-column detection at 200 nm. We obtained the best electropherograms under a condition of 5 mM phosphate-borate (pH 8.5) containing 50 mM SDS and 15% methanol. We examined the effect of the sample solvent matrix on the electropherograms obtained, indicating that increasing the methanol content in the sample solvent or the injection volume above a certain threshold limit decreased the resolution. We then focused on application of the CE to the analysis of the drugs in spiked serum, being appropriate for an analysis within 25 min. Linearity, the detection limit, accuracy and reproducibility were established using this method. The calibration curve was linear up to 1 mg/l of serum concentration. The lower limit of detection was 5 pg per injection and 0.025 mg/l of the serum concentration for all the compounds except for flurazepam, for which they were 40 pg/injection and 0.2 mg/l. The detection limits obtained allowed toxicological and pharmacological determinations for nitrazepam, diazepam, estazolam and bromazepam, but not for triazolam and flurazepam. Only toxic blood levels for the latter two benzodiazepines could be quantified by this method. We concluded that the CE could at least be applicable to simultaneous screening for toxic levels of benzodiazepines. We suggest that this technique may offer criminal toxicologists a rapid, simple and adaptable approach for the estimation of many other drugs in body fluids.

Rapid and sensitive gas chromatographic determination of estazolam.

The triazolobenzodiazepine estazolam can be quantitated by gas chromatography with electron-capture detection. After addition of a suitable internal standard, plasma samples are extracted into toluene-isoamyl alcohol or benzene-isoamyl alcohol. The organic extract is separated, evaporated to dryness, reconstituted, and chromatographed using a 50:50 methyl-phenyl column (SP-2250). The sensitivity limit is approximately 1 ng of estazolam in a 1-ml sample. The method is suitable for clinical or experimental pharmacokinetic studies.

Interactive effects of ethanol on benzodiazepines levels in blood and brain of rat.

Effects of ethanol administration on triazolam, estazolam, diazepam, and chlordiazepoxide levels in blood and brain were investigated using rats. The brain level of triazolam was significantly increased by the concomitant oral administration of ethanol though the blood level was scarcely influenced. Estazolam levels in the blood and brain tended to be markedly raised by the ethanol administration. Diazepam levels in the blood and brain showed a tendency to be a little increased by the ethanol administration. Chlordiazepoxide levels in the blood and brain were scarcely influenced by the ethanol treatment. It was suggested that reinforcement effect of ethanol on the central nervous system depressant actions of triazolam and estazolam might appear by potentiation.

Simultaneous HPLC analysis of the hypnotic benzodiazepines nitrazepam, estazolam, flunitrazepam, and triazolam in plasma.

A new analytical methodology was developed for simultaneous high-performance liquid chromatographic quantitation of nitrazepam, estazolam, flunitrazepam, and triazolam in plasma. After addition of the internal standard nor-prazepam, biological samples and calibration standards were extracted at basic pH into diethyl ether-methylene chloride (2:1, v/v). The reconstituted extract was separated on a reversed-phase Nova Pak C18 column with acidic buffer (6mM)-acetonitrile-methanol (64:23:13, v/v) as mobile phase. The detection was performed at 242 nm. Within-run and day-to-day precision values were about 2-8%. The method is thus sensitive and reproducible for use in clinical and experimental toxicokinetic studies.

The clinical pharmacokinetics of single doses of estazolam.

The pharmacokinetics of estazolam were examined in 17 healthy male subjects. Plasma concentration-time profiles were compared following the oral administration of one 1-mg tablet, two 1-mg tablets, and one 2-mg tablet. No statistically significant differences were detected among the mean time of maximal plasma concentration (Tmax), maximal plasma concentration (Cmax), area under the plasma concentration-time curve from zero to 72 hours (AUC), or half-life values for the 2-mg doses. Mean Cmax was 97.7 and 98.6 ng/ml and mean Tmax was 1.9 and 1.6 hours for two 1-mg tablets and one 2-mg tablet, respectively. Proportionately decreased Cmax and AUC were observed following the 1-mg dose. Mean Cmax was 54.7 ng/ml for the 1-mg dose. Mean Tmax and elimination half-life values were similar to those observed after the 2-mg doses. The overall harmonic mean half-life was 14.4 hours.

A new method for the determination in blood and urine of a novel triazolobenzodiazepine (estazolam) by HPLC.

In this study the authors report a new method to determine estazolam in blood and urine by high pressure liquid chromatography (HPLC). This compound is a triazolobenzodiazepine and shows an interesting psychopharmacological activity. The extraction from biological fluids was carried out using a mixture of ethylenechloride, methylenechloride, and ethylacetate (1:1:8). The HPLC analysis was carried out with a C18 column, using methanol:phosphate buffer (pH 7.5, 0.011M):acetonitrile (65:33:2) as mobile phase. The detector was set at lambda = 240 nm. The method shows good repeatability and a linear response in the range of 0.6 to 10 micrograms estazolam/mL both in serum and urine. A case of non-lethal acute intoxication in which the method was applied is also reported.