Low doses of ethanol markedly potentiate the anti-seizure effect of diazepam in a mouse model of difficult-to-treat focal seizures.

Ethanol is commonly used as a solvent in injectable formulations of poorly water-soluble drugs. The concentrations of ethanol in such formulations are generally considered reasonably safe. It is long known that ethanol can potentiate central effects of sedatives and tranquillizers, particularly the benzodiazepines, most likely as a result of a synergistic interaction at the GABAA receptor. However, whether this occurs at the low systemic doses of ethanol resulting from its use as solvent in parenteral formulations of benzodiazepines is not known. In the present study we evaluated whether a commercial ethanol-containing aqueous solution of diazepam exerts more potent anti-seizure effects than an aqueous solution of diazepam hydrochloride or an aqueous emulsion of this drug in the intrahippocampal kainate model of temporal lobe epilepsy in mice. Spontaneous epileptic seizures in this model are known to be resistant to major antiepileptic drugs. Administration of the ethanol-containing formulation of diazepam caused an almost complete suppression of seizures. This was not seen when the same dose (5 mg/kg) of diazepam was administered as aqueous solution or emulsion, although all three diazepam formulations resulted in similar drug and metabolite concentrations in plasma. Our data demonstrate that ethanol-containing solutions of diazepam are superior to block difficult-to-treat seizures to other formulations of diazepam. To our knowledge, this has not been demonstrated before and, if this finding can be translated to humans, may have important consequences for emergency treatment of acute seizures, series of seizures, and initial treatment of status epilepticus in patients.

Direct determination of diazepam and its glucuronide metabolites in human whole blood by µElution solid-phase extraction and liquid chromatography-tandem mass spectrometry.

A µElution solid-phase extraction (SPE) liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of diazepam, nordiazepam, oxazepam, oxazepam glucuronide, temazepam and temazepam glucuronide in human whole blood is presented. 200 µL of whole blood samples were loaded onto a Waters Oasis HLB 96-well µElution SPE plate using 75 µL of methanol as the elution solvent, and the eluents were injected into an Eclipse XDB C18 column. No hydrolysis, solvent transfer, evaporation or reconstitution was involved in the sample preparation procedures. Tandem mass spectrometric detection with Turbo Ion Spray was conducted via multiple reaction monitoring (MRM) under positive ionization mode. The method was validated and proved to be accurate (accuracy within 93-108%), precise (intra-day RSD<9.9% and inter-day RSD<7.2%) and sensitive with limits of detection (LOD) in the range of 0.05-0.25 ng/mL for all the compounds. Extraction recoveries were in the range of 31-80% for all the analytes. This method demonstrated to be reproducible and reliable. The applicability of the method was demonstrated by analysis of several forensic cases involving diazepam and its metabolites.

Quantification of total and unbound concentrations of lorazepam, oxazepam and temazepam in human plasma by ultrafiltration and LC-MS/MS.

BACKGROUND: A fast and sensitive assay for quantifying total and unbound concentrations of lorazepam (Lzp), oxazepam (Ozp) and temazepam (Tzp) in human plasma was needed for a plasma protein binding study. RESULTS: Plasma samples were precipitated with acetonitrile for determination of total concentrations or subjected to ultrafiltration for determination of unbound concentrations. An LC-MS/MS assay was developed with an Allure® PFP propyl column and a mobile phase of 35% acetonitrile/0.1% formic acid over 4.5 min and ESI+-MS/MS detection. Matrix effects were negligible in plasma and approximately 70% in ultrafiltrate but were accounted for by the internal standards Lzp-d4, Ozp-d5 and Tzp-d5. The assay was validated for total concentrations of 10-100 ng/ml Lzp, 200-2000 ng/ml Ozp and 100-1000 ng/ml Tzp, and for unbound concentrations of 1-10 ng/ml Lzp, 20-200 ng/ml Ozp and 10-100 ng/ml Tzp. Precision was <14% CV and accuracy was 96-110% throughout the calibration range. The mean precision of triplicate analysis of 60 study samples was <4% CV for total and <8% CV for unbound concentrations. CONCLUSION: A fast and sensitive assay was developed and validated. It has been applied successfully to a protein binding study.

Biotransformation of diazepam in a clinically relevant flat membrane bioreactor model using primary porcine hepatocytes.

In vitro biotransformation of drug using commercial culture medium with serum may not be the ideal culture medium for clinical application in extracorporeal bioartificial liver support (BAL) systems. In these systems, patient's blood or plasma is plumbed to primary hepatocytes within a seeded bioreactor, creating interaction between plasma and seeded hepatocytes. To address this situation, we investigated the biotransformation potential of diazepam in primary porcine hepatocytes with a flat membrane bioreactor (FMB); we used human plasma exposure and serum-free media in organotypical double gel culture model for long-term culture. We investigated diazepam clearance and all major metabolites of diazepam, such as oxazepam, temazepam, and desmethyldiazepam, in conventional single gel and organotypical sandwich models and compared them to the FMB model. Diazepam elimination was higher in double gel cultures with exposure to both SF 3 medium conditions and plasma, when compared to the single gel model in a Petri dish. It was observed that in the FMB, diazepam elimination was stable at about 3 pg/h/cell in plasma and SF 3 exposure. Oxazepam synthesis in the bioreactor was approximately one quarter less than in the Petri dish, but there were no differences between N-desmethyldiazepam and temazepam synthesis in double gel culture. In the flat membrane bioreactor, there was no decrease in the biotransformation of diazepam in plasma exposure compared with the control group. Our results suggest that this plasma exposure bioreactor may offer a useful approach in clinical use of extracorporeal BAL, as well as for drug metabolite investigation into toxicological research.

Simultaneous analysis of diazepam and its metabolites in rat plasma and brain tissue by HPLC-UV and SPE.

Diazepam is frequently used as an adjuvant during antidepressant therapy. Recently, some studies have suggested that the treatment with benzodiazepines could have different efficacy in depressed patients as opposed to non-depressed ones. To clarify the matter, a study is currently underway, regarding the drug metabolism in rats. In order to obtain a more complete and significant set of data, the main diazepam metabolites have also been considered, namely: nordiazepam, temazepam and oxazepam. A feasible and reliable HPLC method has been developed for the simultaneous determination of these compounds in plasma and brain tissue of rats. The method has been applied to "normal" rats and to genetic rat models of depression in order to estimate drug metabolism in different breeds. Analyte separation was achieved on a C8 reversed phase column using an acidic phosphate buffer/acetonitrile mixture as the mobile phase. The detection wavelength was 238 nm. An original sample pre-treatment, based on solid-phase extraction (SPE) was developed in order to eliminate endogenous interference, using only 250 microL of matrix (brain homogenate or plasma) for a complete analysis. The method has been validated with good results in terms of precision, extraction yield, sensitivity, selectivity and accuracy on both matrices and has been successfully applied to samples from some rats subjected to the preliminary study. The obtained data will hopefully contribute to the clarification of possible differences between depressed and non-depressed subjects with respect to benzodiazepine biotransformation.

Highway driving in the elderly the morning after bedtime use of hypnotics: a comparison between temazepam 20 mg, zopiclone 7.5 mg, and placebo.

A major problem related to hypnotic drug use is residual sedation the morning after bedtime administration. This constitutes a particular safety hazard for patients who have to drive a car the next morning. Information on the severity of residual effects is mainly derived from studies conducted with young healthy volunteers. However, most users of hypnotics are older people who may be more sensitive to drug effects. The aim of this study was to evaluate the residual effects the morning after evening doses of temazepam 20 mg and zopiclone 7.5 mg on driving performance in healthy elderly drivers. Eighteen healthy elderly drivers (10 females and 8 males; mean age, 64.3 years) participated in a double-blind, 3-way crossover study. Treatments were single oral doses of temazepam 20 mg, zopiclone 7.5 mg, and placebo administered at bedtime. Subjects performed a standardized highway driving test between 10 and 11 hours after hypnotic intake. Before and after the driving test, cognitive performance was assessed. Driving performance did not differ between temazepam and placebo but was significantly impaired after zopiclone 7.5 mg (P < 0.002). The results of the laboratory tests were in line with the effects on driving of both hypnotics. Temazepam 20 mg is unlikely to impair driving 10 hours or more after bedtime administration in healthy elderly aged 75 years or younger. Zopiclone 7.5 mg moderately impairs driving in the elderly at least until 11 hours after administration. The magnitude of impairing effects in the elderly was comparable with those found previously in younger volunteers.

Effects of 2-week treatment with temazepam and diphenhydramine in elderly insomniacs: a randomized, placebo-controlled trial.

A randomized, controlled, crossover clinical study compared 14-night treatment with 15 mg temazepam, 50 mg diphenhydramine, and placebo in elderly individuals with insomnia (mean age, 73.9 years; range, 70-89 years). Primary outcome measures were subjective assessments of sleep recorded on sleep diaries. Secondary measures were the morning-after psychomotor impairment, using the digit symbol substitution task and the manual tracking task, and the morning-after memory impairment, using a free-recall procedure. Results showed sleep improvements with 15 mg temazepam compared with placebo-sleep quality (mean score, 3.3 +/- 0.9 vs 2.9 +/- 0.8; P = 0.03), total sleep time (6.9 +/- 1.0 hours vs 6.3 +/-1.3 hours; P = 0.02), number of awakenings (1.5 +/- 1.3 vs 2.0 +/- 1.2; P < 0.001), and sleep-onset latency (25 +/- 22 minutes vs 37 +/- 25 minutes; P = 0.03). Improvements were seen with diphenhydramine treatment compared with placebo on the number of awakenings only (mean, 1.7 +/- 1.1 vs 2.0 +/- 1.2; P < 0.05). Numbers of adverse events reported were similar after all treatments, although there was 1 fall during temazepam treatment. Findings indicate that temazepam is more effective than diphenhydramine when compared with placebo at the doses tested, although this advantage is mitigated by the risk of falls associated with temazepam use. The choice of agent to use in the elderly must consider these relative benefits and risks.

Associations between use of benzodiazepines or related drugs and health, physical abilities and cognitive function: a non-randomised clinical study in the elderly.

OBJECTIVE: To describe associations between the use of benzodiazepines or related drugs (BZDs/RDs) and health, functional abilities and cognitive function in the elderly. METHODS: A non-randomised clinical study of patients aged > or =65 years admitted to acute hospital wards during 1 month. 164 patients (mean age +/- standard deviation [SD] 81.6 +/- 6.8 years) were admitted. Of these, nearly half (n = 78) had used BZDs/RDs before admission, and the remainder (n = 86) were non-users. Cognitive ability was assessed by the Mini-Mental State Examination (MMSE). Patients scoring > or =20 MMSE sum points were interviewed (n = 79) and questioned regarding symptoms and functional abilities during the week prior to admission. Data on use of BZDs/RDs before admission, current medications and discharge diagnoses were collected from medical records. Health, physical abilities and cognitive function were compared between BZD/RD users and non-users, and adjustments were made for confounding variables. The residual serum concentrations of oxazepam, temazepam and zopiclone were analysed. RESULTS: The mean +/- SD duration of BZD/RD use was 7 +/- 7 years (range 1-31). Two or three BZDs/RDs were concomitantly taken by 26% of users (n = 20). Long-term use of these drugs was associated with female sex and use of a higher number of drugs with effects on the CNS, which tended to be related to diagnosed dementia. After adjustment for these variables as confounders, use of BZDs/RDs was not associated with cognitive function as measured by the MMSE. However, use of BZDs/RDs was associated with dizziness, inability to sleep after awaking at night and tiredness in the mornings during the week prior to admission and with stronger depressive symptoms measured at the beginning of the hospital stay. Use of BZDs/RDs tended to be associated with a reduced ability to walk and shorter night-time sleep during the week prior to admission. A higher residual serum concentration of temazepam correlated with a lower MMSE sum score after adjustment for confounding variables. CONCLUSIONS: Long-term use and concomitant use of more than one BZD/RD were common in elderly patients hospitalised because of acute illnesses. Long-term use was associated with daytime and night-time symptoms indicative of poorer health and potentially caused by the adverse effects of these drugs.

Errors in performance testing: a comparison of ethanol and temazepam.

Both ethanol and benzodiazepines impair psychomotor function. Previous work has suggested that ethanol may have a greater effect on errors while benzodiazepines may cause greater slowing, but this has not been tested in a direct comparison. We assessed the effects of ethanol, at blood concentrations of approximately 80-100 mg/100 ml, compared to two doses of temazepam (20 mg and 30 mg) on psychomotor speed and accuracy and on long-term memory. Sixteen healthy volunteers (eight male, aged 20-25 years) took part in a four-period, placebo-controlled cross-over study. Performance was evaluated using analysis of covariance (critical significance level, p = 0.05) comparing the areas under the response-time curves. Performance on a psychomotor maze showed an almost complete dissociation, with ethanol leading to a substantial and significant increase in errors with little effect on speed, while temazepam slowed performance with no significant change in accuracy. Other tasks showed a similar pattern, but the dissociation was less complete. Handwriting size was substantially increased by ethanol, but not by temazepam. Information processing capacity and long-term memory formation were reduced by a similar amount both for ethanol and 30 mg temazepam. The faster, more error-prone, behaviour on ethanol than with a similarly impairing dose of temazepam has clear implications for the relative potential of the two drugs to contribute to accidents. The results are also important in understanding the differential effects of drugs with different mechanisms of action on human performance.

Fast analysis using monolithic columns coupled with high-flow on-line extraction and electrospray mass spectrometric detection for the direct and simultaneous quantitation of multiple components in plasma.

In this work, monolithic columns were used as a fast separation tool for multiple-component quantitative liquid chromatography-tandem mass spectrometry (LC-MS-MS) assays of drug candidates in biological fluids. A considerably reduced runtime was achieved while maintaining good chromatographic separations. This significantly improved separation speed demanded higher throughput on sample extraction. To this end, monolithic separations were coupled on-line with high-flow extraction, which allowed for the fast extraction and separation of samples containing multiple analytes. An evaluation of this system was performed using a mixture of fenfluramine, temazepam, oxazepam, and tamoxifen in plasma. A total cycle time of 1.2 min was achieved which included both sample extraction and subsequent monolithic column separation via column switching. A total of over 400 plasma samples were analyzed in less than 10 h. The sensitivity and responses were reproducible throughout the run. The system has been routinely used in the authors' laboratory for high-throughput quantitation of compounds in biological fluids in support of drug discovery programs. The assay for samples from a 9-in-1 dog pharmacokinetic study is shown as an example to demonstrate the capability of this system.

High-speed gradient parallel liquid chromatography/tandem mass spectrometry with fully automated sample preparation for bioanalysis: 30 seconds per sample from plasma.

In this work, a high-throughput and high-performance bioanalytical system is described that is capable of extracting and analyzing 1152 plasma samples within 10 hours. A Zymark track robot system interfaced with a Tecan Genesis liquid handler was used for simultaneous solid-phase extraction of four 96-well plates in a fully automated fashion. The extracted plasma samples were injected onto four parallel monolithic columns for separation via a four-injector autosampler. The use of monolithic columns allowed for fast and well-resolved separations at a considerably higher flow rate without generating significant column backpressure. This resulted in a total chromatographic run cycle time of 2 min on each 4.6 x 100 mm column using gradient elution. The effluent from the four columns was directed to a triple quadrupole mass spectrometer equipped with an indexed four-probe electrospray ionization source (Micromass MUX interface). Hence, sample extraction, separation, and detection were all performed in a four-channel parallel format that resulted in an overall throughput of about 30 s per sample from plasma. The performance of this system was evaluated by extracting and by analyzing twelve 96-well plates (1152) of human plasma samples spiked with oxazepam at different concentrations. The relative standard deviation (RSD) of analyte sensitivity (slope of calibration curve) across the four channels and across the 12 plates was 5.2 and 6.8%, respectively. An average extraction recovery of 77.6% with a RSD of 7.7% and an average matrix effect of 0.95 with a RSD of 5.2% were achieved using these generic extraction and separation conditions. The good separation efficiency provided by this system allowed for rapid method development of an assay quantifying the drug candidate and its close structural analog metabolite. The method was cross-validated with a conventional liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay.

Drug related deaths in the Strathclyde region of Scotland, 1995-1998.

The misuse of drugs, both illicit and prescribed has increased dramatically in the west of Scotland over the last few decades. Consequently, the number of drug related deaths has risen as a direct result. Since, discrepancies exist between data collected by the Department of Forensic Medicine and Science, University of Glasgow and official statistics, this project, was funded to investigate all known drug related deaths that occurred within the Strathclyde region of Scotland in an effort to improve the accuracy of statistics and the dissemination of information pertaining to them. Changes in medical treatment, legislation and patterns of drug taking were noted and the effects of these on the year-by-year death tolls evaluated.

The simultaneous determination of diazepam and its three metabolites in dog plasma by high-performance liquid chromatography with mass spectroscopy detection.

A fast, sensitive and specific LC/MS/MS method for the simultaneous determination of diazepam and its three metabolites, oxazepam, temazepam and desmethyldiazepam, in dog plasma is described. The method consists of an automated 96-well solid phase extraction procedure and electrospray LC/MS/MS analysis. D(5)-Diazepam is used as the internal standard for all the compounds. Intra-day and inter-day assay coefficients of variations are less than 12.7%. The lower limit of quantitation (LLOQ) is 1 nM for each analyte, based on 0.1 ml aliquots of dog plasma. The analytical run time was 5 min. Linearity is observed over the range of 1--500 nM. This method has been used to support the discovery of pharmacokinetic studies.

High-speed liquid chromatography/tandem mass spectrometry using a monolithic column for high-throughput bioanalysis.

With the ever-increasing workload from a variety of in vitro and in vivo screening procedures, new analytical methodologies to perform bioanalysis in an accurate and high-throughput manner are in great demand. In this work, monolithic columns were used instead of conventional particulate HPLC columns to perform chromatographic separations. Because the pressure drop on a monolithic column was considerably lower than that on a particulate column, a high flow rate (6 mL/min) was used for a 4.6 x 50 mm monolithic column with a total backpressure of about 61 bar measured using acetonitrile/water (50:50). The capability of using a regular column length at high flow rates, combined with the extremely small dependency of separation efficiency on linear flow velocity, allowed for the generation of sufficient chromatographic resolving power in a significantly reduced runtime. As demonstrated in this work, a plasma extract of a mixture of tempazepam, tamoxifen, fenfluramine, and alprozolam were baseline separated within a total analysis time of one minute. An average peak width at half maximum of approximately one second was noted using a generic broad gradient. It was also found that the separation efficiency and signal/noise (S/N) ratios for this separation remained almost constant at flow rates of 1, 3, and 6 mL/min, respectively. The ruggedness of the separation was evaluated by injecting 600 plasma extracts containing the replicates of a standard curve of the above mixture during an overnight run. The chromatographic retention time, separation quality, peak response and sensitivity were highly reproducible throughout the run. This high-speed liquid chromatography/tandem mass spectrometry (LC/MS/MS) system has been used routinely in the authors' laboratory to support drug discovery programs.

Efficacy of activated charcoal versus gastric lavage half an hour after ingestion of moclobemide, temazepam, and verapamil.

OBJECTIVE: To compare the efficacy of activated charcoal and gastric lavage in preventing the absorption of moclobemide, temazepam, and verapamil 30 min after drug ingestion. METHODS: In this randomized cross-over study with three phases, nine healthy volunteers received a single oral dose of 150 mg moclobemide, 10 mg temazepam, and 80 mg verapamil after an overnight fast. Thirty minutes later, they were assigned to one of the following treatments: 25 g activated charcoal as a suspension in 200 ml water, gastric lavage (10x200 ml), or 200 ml water (control). Plasma concentrations of moclobemide, temazepam, and verapamil were determined up to 24 h. RESULTS: Activated charcoal reduced the area under the plasma concentration time curve from 0 h to 24 h (AUC0-24 h) of moclobemide and temazepam by 55% (P<0.05) and by 45% (P<0.05), respectively. The AUC0-24 h of verapamil was not significantly reduced by charcoal. Gastric lavage decreased the AUC0-24 h of moclobemide by 44% (P<0.05), but had no significant effect on that of temazepam or verapamil. The peak plasma concentration (Cmax) of moclobemide, temazepam, and verapamil was reduced by 40%, 29% (P<0.05), and 16%, respectively, by activated charcoal. Gastric lavage did not significantly decrease the Cmax of any of these drugs. CONCLUSION: The absorption of moclobemide, temazepam, and verapamil can be moderately reduced by activated charcoal given 30 min after drug ingestion, while gastric lavage seems to be less effective.

Benzodiazepine findings in blood and urine by gas chromatography and immunoassay.

Gas chromatography (GC) and immunoassay techniques applied to blood and urine specimens were compared for the screening of benzodiazepines in postmortem forensic toxicology. Five hundred and six such successive postmortem cases in which both urine and peripheral blood was sent for toxicological analysis by the medical examiners were selected. The urine specimens were tested by the Emit((R)) d.a.u. Benzodiazepine Assay, and in parallel, the blood and urine specimens were screened for benzodiazepine drugs and their metabolites by an established automated dual-column GC method. The lowest number of positives (153) was obtained when immunoassay was performed without enzyme hydrolysis. When urine samples were hydrolysed before immunoassay, the number of positives increased to 175. The highest number of positives (200) was obtained in urine by GC, and the screening of blood by GC yielded 185 quantitative results. Despite the urine GC screening produced the most positives, the quantitative screening of the blood by GC appears to be the most efficient approach in postmortem forensic toxicology, considering the fact that although urine findings confirm the presence of the drug, quantitative results in urine are irrelevant to acute toxicity.

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.

The urinary elimination profiles of diazepam and its metabolites, nordiazepam, temazepam, and oxazepam, in the equine after a 10-mg intramuscular dose.

A method for the extraction of diazepam and its metabolites (nordiazepam, temazepam, and oxazepam) from equine urine and serum and their quantitation and confirmation by liquid chromatography-tandem mass spectrometry is presented. Valium, a formulation of diazepam, was administered at a dose of 10 mg intramuscularly to four standard-bred mares. Diazepam is extensively metabolized in the horse to nordiazepam, temazepam, and oxazepam. Diazepam urinary concentrations were found to be less than 6 ng/mL. Nordiazepam was found to be mainly in its glucuronide-conjugated form and was measured out to a collection time of 53-55 h. Oxazepam and temazepam were entirely conjugated, and their urinary concentrations were measured out to collection times of 121 h and 77-79 h, respectively. Diazepam and nordiazepam were measured in equine postadministration serum out to collection times of 6 and 54 h, respectively. Oxazepam and temazepam were not detected in postadministration serum.

Rapid and simple chromatographic method for the determination of diazepam and its major metabolites in human plasma and urine.

A simple, rapid, sensitive and selective HPLC method has been developed for the analysis of diazepam (DZP) and its major metabolites, N-desmethyldiazepam (DMDZP), temazepam (TZP) and oxazepam (OZP), in plasma and urine, using clonazepam (CZP) as the internal standard and chloroform as the extracting solvent, with a 10 ng/ml limit of quantitation for the four assayed drugs, and an average (+/-S.D.) recovery of 87.7+/-6.46%, 92.9+/-5.31%, 91.4+/-4.01% and 91.7+/-2.68% for DZP, DMDZP, TZP and OZP, respectively (from plasma), and 89.6+/-2.26%, 90+/-4.24%, 87.45+/-0.64% and 94.50+/-0.71% for DZP, DMDZP, TZP and OZP, respectively (from urine). The method has also proved to be selective and reproducible.

Drug concentration in selected skeletal muscles.

We evaluated the homogeneity of drug concentrations in muscle in 14 cadavers, comprising 11 drug overdoses and three cases of chronic therapeutic drug use. Analyses were performed on samples from twelve named muscles and femoral venous blood. Standard analytical techniques and instrumentation were used throughout. There was marked within-case variability in drug concentrations with highest:lowest concentrations ranging up to 21.7. Overall highest concentrations were found in the diaphragm and mean diaphragm:blood ratios ranged from 1.1 (temazepam, two cases) and 1.2/1.3 (paracetamol, six cases) up to 6.5/13.5 (amitriptyline, three cases) and 5.3/21.3 (propoxyphene, four cases). Excluding the diaphragm, mean muscle:blood ratios ranged from 0.4 (prothiaden), 0.5 (temazepam), and 0.7 (paracetamol) up to 3.7 (temazepam), 4.3 (propoxyphene) and 5.7 (amitriptyline). We suggest that muscle is suitable for qualitative analysis but not for quantitative corroboration of a blood sample or as a quantitative alternative to blood.