Occurrence of Z-drugs, benzodiazepines, and ketamine in wastewater in the United States and Mexico during the Covid-19 pandemic

Z-drugs, benzodiazepines and ketamine are classes of psychotropic drugs prescribed for treating anxiety, sleep disorders and depression with known side effects including an elevated risk of addiction and substance misuse. These drugs have a strong potential for misuse, which has escalated over the years and was hypothesized here to have been exacerbated during the COVID-19 pandemic. Wastewater-based epidemiology (WBE) constitutes a fast, easy, and relatively inexpensive approach to epidemiological surveys for understanding the incidence and frequency of uses of these drugs. In this study, we analyzed wastewater (n = 376) from 50 cities across the United States and Mexico from July to October 2020 to estimate drug use rates during a pandemic event. Both time and flow proportional composite and grab samples of untreated municipal wastewater were analyzed using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry to determine loadings of alprazolam, clonazepam, diazepam, ketamine, lorazepam, nordiazepam, temazepam, zolpidem, and zaleplon in raw wastewater. Simultaneously, prescription data of the aforementioned drugs were extracted from the Medicaid database from 2019 to 2021. Results showed high detection frequencies of ketamine (90 %), lorazepam (87 %), clonazepam (76 %) and temazepam (73 %) across both Mexico and United States and comparatively lower detection frequencies for zaleplon (22 %), zolpidem (9 %), nordiazepam (<1 %), diazepam (<1 %), and alprazolam (<1 %) during the pandemic. Average mass consumption rates, estimated using WBE and reported in units of mg/day/1000 persons, ranged between 62 (temazepam) and 1100 (clonazepam) in the United States. Results obtained from the Medicaid database also showed a significant change (p < 0.05) in the prescription volume between the first quarter of 2019 (before the pandemic) and the first quarter of 2021 (pandemic event) for alprazolam, clonazepam and lorazepam. Study results include the first detections of zaleplon and zolpidem in wastewater from North America.

Pharmacokinetics of Diazepam and Its Metabolites in Urine of Chinese Participants

BACKGROUND

Urine is conventionally used as a specimen to document diazepam-related crimes; however, few reports have described the pharmacokinetics of diazepam and its metabolites in urine.

OBJECTIVE

This study aimed to investigate the pharmacokinetics of diazepam and its metabolites, including glucuronide compounds, in the urine of Chinese participants.

METHODS

A total of 28 volunteers were recruited and each participant ingested 5 mg of diazepam orally. Ten milliliters of urine were collected from each participant at post-consumption timepoints of prior (zero), 1, 2, 4, 8, 12, and 24 h and 2, 3, 6, 12, and 15 days. All samples were extracted by solid-phase extraction and analyzed using high-performance liquid chromatography-tandem mass spectrometry. Diazepam and its main metabolites, except for temazepam, were detected in the urine of volunteers. Pharmacokinetic parameters were analyzed using the pharmacokinetic software DAS according to the non-compartment model.

RESULTS

Urinary diazepam peaked at 2.38 ng/mL (C_max) and 1.93 h (T_max). The urinary metabolite nordiazepam peaked at 1.17 ng/mL and 100.21 h; temazepam glucuronide (TG) peaked at 145.61 ng/mL and 41.14 h; and oxazepam glucuronide (OG) peaked at 101.57 ng/mL and 165.86 h. The elimination half-life (t_½z) and clearance (CLz/F) for diazepam were 119.58 h and 65.77 L/h, respectively. The t_½z of the metabolites nordiazepam, TG, and OG was 310.58 h, 200.17 h, and 536.44 h, respectively. Finally, this study found that both diazepam and its main metabolites in urine were detectable for at least 15 days, although there were individual differences.

CONCLUSION

The results regarding diazepam pharmacokinetics in urine would be of great help in forensic science and drug screening.

A comparative study of primary secondary amino (PSA) and multi-walled carbon nanotubes (MWCNTs) as QuEChERS absorbents for the rapid determination of diazepam and its major metabolites in fish samples by high-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry

BACKGROUND

A simple and fast modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method is presented for the determination of diazepam and its three major metabolites, nordiazepam, temazepam and oxazepam (benzodiazepines) in fish samples by liquid chromatography-electrospray ionisation-tandem mass spectrometry.

RESULTS

Muscle tissues were extracted with acetonitrile, and then cleaned with primary secondary amino (PSA) adsorbents. The cleanup effect of PSA was compared with that of multi-walled carbon nanotubes (MWCNTs) in term of extraction efficiency. The better results were obtained when PSA was used. The chromatography separation was achieved within 5.0 min on a C18 column. The limit of detection was 0.5 µg kg(-1) and the limit of quantification was 2.5 µg kg(-1). Average recoveries of diazepam and its main metabolites were in the range of 88.5-110.1%, with a relative standard deviation lower than 10.0%.

CONCLUSION

The proposed method for fish samples gives good recoveries, linearity, precision and accuracy.

Diazepam and its metabolites in the mothers' and newborns' hair as a biomarker of prenatal exposure

Pregnant women are exposed to benzodiazepines for therapeutic purposes during gestation. The goal of this study was to evaluate prenatal exposure to benzodiazepines. Time of exposure during course of pregnancy is a significant aspect of fetal exposure to drugs. Benzodiazepine concentration assay in hair of mothers and newborns exposed prenatally to these drugs was performed in the studies. Development, validation and evaluation of benzodiazepine determination method in mothers and their newborns enables assessment of health risks for the child and implementation of adequate therapeutic procedures. We used A LC-ESI-MS/MS method that allowed determination of diazepam (the main benzodiazepine used by pregnant women was diazepam) and its metabolites (nordazepam, oxazepam) in hair of mothers and newborns. LOQ 10 pg/mg of hair was used in the study.

RESULTS

concentration of nordazepam was higher than parent drug (diazepam) and higher in newborns' hair when compared to mothers'. The mean concentrations of diazepam in mothers' hair were 31.6±36.0 and 34.1±42.4 pg/mg in the second and third trimester of pregnancy respectively. The mean concentration of diazepam in newborns' hair was higher and reached levels of 53.3±36.5 pg/mg. The mean concentration of nordazepam in the mothers' hair corresponding to the second and third trimester was 52.9±48.1 and 89.9±122.8 pg/mg, respectively. Nordazepam in the newborns' hair was detected at the mean level of 108.1±144.2 pg/mg. It was concluded that diazepam and nordazepam are permanently incorporated into the hair structure. Presence of diazepam and its metabolites in newborn's hair confirms that these benzodiazepines permeate placental barrier. Segmental analysis of mothers' hair enabled the assessment of drug administration time. Diazepam and its metabolites determined in hair of newborns may serve as biomarkers of prenatal exposure to these drugs. The performed LC-MS/MS analysis was accurate enough to determine even low concentrations of benzodiazepines, at the level of few pg/mg of hair. Levels of diazepam detected in hair of newborns were higher than levels determined in mothers. This may confirm the fact, that fetus's ability to metabolize diazepam is scarce. Nordazepam was found in higher concentrations in hair of newborns than in hair of mothers, which may suggest that it is cumulated in child's organism. Other metabolites of diazepam--oxazepam and temazepam--were detected in very few cases, in low concentrations.

Buprenorphine in Drug-Facilitated Sexual Abuse: A Fatal Case Involving a 14-Year-Old Boy

The first case involving repetitive sexual abuse linked to the use of buprenorphine is reported. Under the tradename Subutex, buprenorphine is largely used for the substitution management of opiate-dependent individuals, but it can also be easily found on the black market. A 14-year-old boy was found dead at the home of a well-known sex offender of minors. At the autopsy, no particular morphological changes were noted, except for pulmonary and visceral congestion. There was no evidence of violence, and no needle marks were found by the pathologist. Toxicological analyses, as achieved by liquid chromatography-mass spectrometry, demonstrated both recent and repetitive buprenorphine exposure in combination with nordiazepam. Buprenorphine concentrations were 1.1 ng/mL and 23 pg/mg in blood and hair, respectively. The boy's death was attributed to accidental asphyxia in a facilitated repetitive sexual abuse situation due to the combination of buprenorphine and benzodiazepines, even at therapeutic concentrations. The use of buprenorphine as a sedative drug was not challenged by the perpetrator.

Liquid-phase microextraction as a sample preparation technique prior to capillary gas chromatographic-determination of benzodiazepines in biological matrices

Liquid-phase microextraction (LPME) and gas chromatography were applied to determine diazepam and the main metabolite N-desmethyldiazepam in human urine and plasma. The analytes were extracted from 3.0-3.5 ml sample volumes directly into 25 microl of extraction solvent. The microextraction device consisted of a porous hollow fiber of polypropylene attached to two guiding needles inserted through a septum and a 4 ml vial. The hollow fiber filled with extraction solvent was immersed in sample solution. The extraction device was continuously vibrated at 600 rpm for 50 min. An aliquot (1 microl) of the extraction solvent with preconcentrated analytes was injected directly into the capillary gas chromatograph. Thirty samples were extracted simultaneously on the vibrator, providing a high sample capacity. The limits of detection were from 0.020 to 0.115 nmol/ml for diazepam and N-desmethyldiazepam in plasma and urine using a nitrogen-phosphorus detector (NPD).

Determination of benzodiazepines in human urine and plasma with solvent modified solid phase micro extraction and gas chromatography; rationalisation of method development using experimental design strategies

Solid phase micro extraction (SPME) and gas chromatographic analysis was used for the analysis of several benzodiazepines (oxazepam, diazepam, nordiazepam, flunitrazepam and alprazolam) in human urine and plasma. Several factors likely to affect the analyte recovery were screened in a fractional factorial design in order to examine their effect on the extraction recovery. Parameters found significant in the screening were further investigated with the use of response surface methodology. The final conditions for extraction of benzodiazepines were as follows: Octanol was immobilised on a polyacrylate fibre for 4 min. The fibre was placed in the sample and extraction took place at pH 6.0 for 15 min. Urine samples were added to 0.3 g ml(-1) sodium chloride. In plasma, the extraction recovery was less than in urine and releasing the benzodiazepines from plasma proteins followed by protein precipitation was found necessary prior to sampling. The method was validated and found linear over the range of samples. The limits of detection in urine were determined to be in the range 0.01-0.45 micromol l(-1). The corresponding limits of detection in plasma were in the range 0.01-0.48 micromol l(-1). Finally, the method developed was applied to determine some benzodiazepines after administration of a single dose. This method offers sufficient enrichment for bioanalysis after a single dose of high dose benzodiazepines as diazepam, but for low dose benzodiazepines as flunitrazepam, further sensitivity is needed.

[Possibilities for toxicologic evidence in adipocere formation and postmortem interval of several years]

It is reported on a 31-year-old man, whose dead body was found together with numerous packets of poisons and medicaments in a forest after a post-mortem period of nearly 3 years. Despite advanced skeletization and complete transformation of the still existing residual soft tissues to adipocere, highly toxic concentrations of two heavy metals (cadmium: 0.30 mg/kg; thallium: 0.91 mg/kg) and minor levels of three organic substances (phenobarbitone: 0.32 mg/kg; nordazepam: 0.14 mg/kg; salicylic acid: 0.04 mg/kg) were detected in adipoceratous samples. Even if it is not possible to derive similar blood levels from post-mortem values, the cause and manner of death (suicidal intoxication) could be clarified with the necessary degree of certainty. Few comparable literature reports either deal with exhumations or non-toxic concentrations of substances in morphologically better preserved adipoceratous bodies. Our case demonstrates that toxicological analyses may contribute to the clarification of the cause of death even if advanced adipocere formation with a longer post-mortem interval is present.

Application of microdialysis to study the in vitro metabolism of drugs in liver microsomes

Current methods for studying in vitro drug metabolism involve add-incubate-separate-measure approach. Separation of the desired analytes requires removal of protein which is typically accomplished by precipitation and centrifugation and extraction of the analytes into an organic phase. The analysis scheme then becomes more complex resulting in a decrease in precision and an increase in assay time. Microdialysis sampling circumvents these problems by allowing researchers to sample the reaction mixture periodically and obtain the complete metabolic profile. In the present study, microdialysis sampling was used to investigate Phase I metabolism of salicylic acid, diazepam and ibuprofen in rat liver microsomes. The major metabolites of these drugs were profiled by LC. Michaelis-Menten enzyme kinetic parameters, Km and Vmax were obtained for the formation of diazepam metabolites by both microdialysis and conventional microsomal incubations and were in good agreement with the values reported in the literature. This study shows that microdialysis has considerable promise as a sampling technique for in vitro drug metabolism studies. By making minor modifications to the instruments, microdialysis can be applied to other in vitro systems such as isolated hepatocytes to study the Phase II metabolism or tissue slices to study drug distribution.

A fatality due to moclobemide

A fatality due to ingestion of the antidepressant drug moclobemide is reported. Moclobemide is a selective and reversible inhibitor of monoamine oxidase type A. Previous reports have suggested that it is a safe drug even when taken in large quantities. The few reported fatalities have all been ascribed to serotonin syndrome, due to an interaction between moclobemide and other serotonergic agents. A 48-year-old woman with a history of depression and suicide attempts was found deceased at home. Autopsy revealed no evidence of significant natural disease or injury. Toxicologic analysis was performed and drug levels measured by capillary gas chromatography. The blood concentration of moclobemide was 137 mg/L and the liver concentration was 432 mg/kg. Low levels of diazepam, nordiazepam, and trifluoperazine were also detected. Death was considered to be due to acute poisoning by moclobemide. This case report is the first, to our knowledge, where death has been attributed to the toxic effects of moclobemide alone.

Automation of toxicological screenings on a Hewlett Packard Chemstation GC-MS system

OBJECTIVES

To optimize the interpretation of GC-MS toxicological screenings (i.e., to facilitate ion specific queries, create custom reports specifically adapted to each confirmation procedure, and eliminate redundant and/or inaccurate data on library search reports).

DESIGN AND METHODS

The MS Chemstation software of the Hewlett Packard 5972 is constructed in a modular way. We made extensive modifications to two modules, the data analysis and the report modules, using the built-in MS Chemstation macro language.

RESULTS

Ion specific queries were automated for over 60 commonly encountered analytes. Custom reports were created for the confirmation of positive drugs-of-abuse immunoassay results. With the incorporation of decision support rules into the data processing and the reporting phases, we obtained sensitive, accurate, and concise reports.

CONCLUSIONS

The MS Chemstation software can be tailored to the needs of each individual application. The incorporation of a rule-based decision support system enhances the quality of the GC-MS toxicological screenings and results in faster, easier, and more reliable processing.

Hair analysis for nordiazepam and oxazepam by gas chromatography--negative-ion chemical ionization mass spectrometry

A procedure is presented for the identification of nordiazepam and its metabolite, oxazepam, in human hair. The method involves decontamination of hair with dichloromethane, incubation in phosphate buffer (pH 7.6) in the presence of deuterated internal standards, liquid-liquid extraction, derivatization with N,O-bis(trimethylsilyl)trifluoroacetamide plus 1% trimethylchlorosilane and gas chromatography-mass spectrometry using negative-ion chemical ionization with methane. Among thirty samples obtained from polydrug abusers, thirteen tested positive for nordiazepam, in the range of 0.25-18.87 ng/mg. Five samples were also positive for oxazepam, in the range 0.11-0.50 ng/mg.

Elevated brain concentrations of 1,4-benzodiazepines in fulminant hepatic failure

BACKGROUND

Increased gamma-aminobutyric acid (GABA) neurotransmission has been implicated in the pathogenesis of hepatic encephalopathy. The mechanism by which GABA-ergic activity is increased in hepatic failure is unclear, but recent studies in animals with encephalopathy due to fulminant hepatic failure suggest that GABA-ergic neurotransmission may be increased by the presence of elevated concentrations of benzodiazepine agonists such as diazepam and N-desmethyldiazepam.

METHODS AND RESULTS

Samples of frontal cortex were obtained at autopsy from 11 patients with hepatic encephalopathy who died of acetaminophen-induced fulminant hepatic failure and 8 patients who died of cardiovascular disease or trauma. None of the 19 patients had received benzodiazepines while hospitalized. Chromatographic analyses of extracts of these samples revealed 4 to 19 peaks representing substances that inhibited the binding of a radiolabeled imidazobenzodiazepine ([3H]flumazenil) to its receptors. Several of these peaks had retention times corresponding to those of known 1,4-benzodiazepines. Ultraviolet- and mass-spectroscopic analysis confirmed that two of these peaks represented diazepam and N-desmethyldiazepam. The patients who died of fulminant hepatic failure could be divided into two groups: six who had had significantly elevated brain concentrations (2-fold to 10-fold higher than normal) of substances inhibiting the binding of [3H]flumazenil and five who had normal concentrations.

CONCLUSIONS

Brain concentrations of substances inhibiting the binding of [3H]flumazenil to its receptors are increased in some patients with hepatic encephalopathy due to fulminant hepatic failure. The origin of these substances is unknown, but these findings provide a rational basis for trials of benzodiazepine-receptor antagonists in the management of this disorder.

Determination of diazepam and nordazepam in milk and plasma in the presence of oxazepam and temazepam

For studies on the excretion of drugs into milk a sensitive high-performance liquid chromatographic assay was developed to quantitate diazepam and nordazepam in the milk and plasma of humans and rabbits in the presence of their major metabolites, oxazepam and temazepam. Flurazepam was used as an internal standard. The assay involves extractions with diethyl ether and an additional acid clean-up step. Chromatographic separation was achieved by a LiChrospher 60 RP-select B (5 microns) column and KH2PO4- acetonitrile (69:31, v/v) adjusted to pH 2.80 as a mobile phase. The same extraction and chromatographic conditions were suited to both types of samples, milk and plasma. The limits of determination using ultraviolet detection at 241 nm was for diazepam 20 ng/ml and for nordazepam 15 ng/ml. The absolute recoveries of diazepam, nordazepam and flurazepam in human milk were 84, 86 and 92% and in human plasma 97, 89 and 94%, respectively. The within- and between-day accuracy and precision for diazepam and nordazepam in milk and plasma at all concentrations tested (20-1500 ng/ml) were better than 8%. The high fat content which occurs in rabbit milk presented no limitation for the extraction of lipophilic diazepam: the method was successfully used to monitor milk and plasma concentrations of diazepam and nordazepam in lactating New Zealand White rabbits during 26-h infusions of diazepam (1.4 mg/h).

Excretion of diazepam and its metabolites in human milk during withdrawal from combination high dose diazepam and oxazepam

The excretion of diazepam, N-desmethyldiazepam, temazepam and oxazepam in breast milk was studied during withdrawal of a 22-year-old patient from combined high dose diazepam and oxazepam therapy. Concentrations of these benzodiazepines in plasma from both the woman and her nursing infant (1 year old) were also documented. Diazepam, N-desmethyldiazepam, temazepam and oxazepam were found in the maternal plasma and milk with mean milk: plasma ratios of 0.2, 0.13, 0.14 and 0.10 respectively. It was calculated on a mg kg-1 basis that the infant received some 4.7% of the maternal dose. Diazepam could not be detected in the infant's plasma, but low levels of N-desmethyldiazepam (20 and 21 micrograms l-1), temazepam (7 micrograms l-1) and oxazepam (7.5 and 9.6 micrograms l-1) were present. The infant showed no overt physical or mental symptoms of benzodiazepine intoxication.

Benzodiazepines: are they of natural origin?

Three research groups have provided evidence that benzodiazepines might be also of natural origin. In the brain of different species including humans and in several plant products, desmethyldiazepam and diazepam are detectable by immunological methods and gas chromatography--mass spectrometry. Thus, benzodiazepines represent natural drugs which may be incorporated into animals and humans through plant products. Whether the measured low concentrations (ranging from 0.01 up to 600 ng/g wet weight) have any biological role or clinical significance remains to be determined.

Sensitive determination of diazepam and N-desmethyldiazepam in human material using capillary gas chromatography-mass spectrometry

A reliable and sensitive capillary gas chromatographic-mass spectrometric method was developed for the detection and determination of diazepam and its major metabolite, N-desmethyldiazepam, in human material. Medazepam served as the internal standard. Quantitative determination was achieved using mass fragmentography with selected ions of m/z 256 for diazepam and m/z 242 for N-desmethyldiazepam and medazepam. The limit of detection was 1 ng/g and the recoveries were 98.54 +/- 3.95% for diazepam and 98.66 +/- 6.48% for N-desmethyldiazepam. The calibration graph was linear over the concentration range from 1.0 ng/g to 1.0 microgram/g for diazepam and N-desmethyldiazepam. Using this method, trace amounts of diazepam and N-desmethyldiazepam were detected in the tissues of an autopsied individual.

Diazepam and N-desmethyldiazepam are found in rat brain and adrenal and may be of plant origin

Benzodiazepine-binding inhibitory (BBI) activity was detected in aqueous extracts of brain and peripheral tissues of rats. The BBI activity in brain and in adrenals was, at least partially, due to the presence of N-desmethyldiazepam and diazepam as shown by HPLC, UV-spectroscopy and mass spectrometry. In addition, BBI activity was found in standardized rat food, as well as in a variety of cereals and in other nutritive plant products. In wheat grains diazepam and N-desmethyldiazepam could be identified by HPLC and analysis by gas chromatography combined with mass spectrometry. The estimated amounts of the two benzodiazepines present in rat brain and adrenals and in wheat grains were in the low ppb range. Since laboratory contamination was rigorously excluded we conclude that diazepam and N-desmethyldiazepam are naturally occurring compounds. These findings may explain their occurrence in the brain and adrenals of animals.

Placental and blood-CSF transfer of orally administered diazepam in the same person

Both placental and blood-lumbar CSF transfer of diazepam (5 mg orally) and its two metabolites, N-desmethyldiazepam and unconjugated oxazepam, was measured (by GLC) in 15 patients undergoing Caesarean section under spinal analgesia. Differing from our earlier studies with atropine (Virtanen et al. 1982; Kanto et al. 1981 & 1987), a reasonably fast penetration of diazepam and its two metabolites through the two biological membranes was found. Diazepam, N-desmethyldiazepam and to a lesser extent unconjugated oxazepam accumulated on the foetal side of the placenta, apparently due to a higher degree of plasma protein binding in the foetus. No accumulation was found in CSF, probably due to the lack of binding proteins in this tissue compartment. Concerning atropine, lumbar CSF with an incomplete drug penetration was found to be a "deeper" compartment than amniotic fluid, but in the present study with diazepam there was no clear difference between these two tissue compartments.

Acute tolerance to diazepam in mice: pharmacokinetic considerations

The tolerance to the hypnotic effect of diazepam developed after a single exposure to diazepam in the presence or absence of cycloheximide, which blocks liver enzyme induction, was studied. At the high dose (30-35 mg/kg) used in this study, diazepam was found to be metabolized very rapidly in mice, consistent with previous findings using a much smaller dose (5 mg/kg). There was no significant difference in the pharmacokinetics of diazepam in control and tolerant mice as observed by monitoring the plasma and brain concentrations of diazepam and N-desmethyldiazepam. It is concluded that acute tolerance to diazepam in mice may not be attributed to changes in pharmacokinetic factors.

Long-lasting anticonvulsant effects of diazepam in different mouse strains: correlations with brain concentrations and receptor occupancy

There were marked strain differences in the duration of the protective effects of diazepam against the convulsant actions of penylenetetrazole and picrotoxin in mice. In no case was significant protection found at 12 h or longer, regardless of whether the incidence of or the latencies to myoclonus or tonic-clonic convulsions were considered. These behavioural differences could not be explained simply in terms of strain differences in benzodiazepine metabolism or in percent of receptor occupancy, as determined by the fractional displacement of 3H-flunitrazepam binding in vivo. It is suggested that there might be strain differences in the percent of receptor occupancy needed in order to produce an anticonvulsant effect.

Radioimmunoassay for determination of prazepam and its metabolites

The development of a radioimmunoassay for the analysis of prazepam and its metabolites is described. It includes the preparation of the immunogen, immunization and measurement of specificity and sensitivity.

Identification of some interferences in the analysis of clorazepate

Clorazepate presents several problems in identification. In addition to rapid acid decarboxylation to N-desmethyldiazepam, a noncontrolled substance often confused with clorazepate, extracts of the pharmaceutical forms (Tranxene and Azene capsules) contain substances that interfere with isolation of intact and unaltered clorazepate. These substances have been identified and have been found to be quite dependent on both capsule type and, especially, on capsule age. The cause of the conversion of dipotassium clorazepate to the monopotassium salt, following solution, has also been identified. An infrared analysis method, which removes all of the interferences, is presented.

Methane negative chemical ionization analysis of 1,3-dihydro-5-phenyl-1,4-benzodiazepin-2-ones

The methane negative chemical ionization (NCI) mass spectra of the medically important 1,3-dihydro-5-phenyl-1,4-benzodiazepin-2-ones generally consisted solely of M- and (M-H)- ions. Attempts to find the location of the H lost in the generation of the (M-H)- ion were unsuccessful, although many possibilities were eliminated. A Hammett correlation analysis of the relative sensitivities of a series of 7-substituted benzodiazepines suggested that the initial ionization takes place at the 4,5-imine bond. For certain benzodiazepines, the (M-H)- ion generated by methane NCI was 20 times more intense than the MH+ ion generated by methane positive chemical ionization (PCI). By using NCI, a sensitive and simple GC-MS assay for nordiazepam was developed that can quantitate this important metabolite of many of the clinically used benzodiazepines in the blood and brain of rats.

[A screening radioimmunoassay for 1,4-benzodiazepines in human blood, serum, and urine using anti-oxazepam-hemisuccinate-antibodies (author's transl)]

A simple and specific radioimmunoassay (RIA) was developed for the determination of oxazepam and other 1,4-benzodiazepines in human blood serum and urine (e.g., diazepam, desmethyldiazepam, chlorazepate). For serum a 1:10 dilution, for urine a 1:100 dilution is recommended. Blood and hemolyzed samples need prior extraction by Amberlite XAD-2. The antisera were raised by immunizing "White New Zealand"-rabbits with an oxazepam-3-hemisuccinate bovine serum albumin conjugate. Using 0.1 ml serum dilution the sensitivity is 0.01 mg/l per tube. Especially higher concentrations show a tendency toward underestimation. Being not limited to a single 1,4-benzodiazepine derivative, the specificity of the antisera is also suitable for a screening analysis. Compared to thin-layer chromatographic analysis of urine this assay shows improved sensitivity (0.05--0.1 mg/l in 0.1 ml of a 1:100 dilution = 1 microliter of urine). For forensic investigations, an analysis in the sequence of urine-RIA, blood/serum-RIA, blood/serum-"electron-capture"-gas-liquid chromatography (ECD-GLC) seems to be a helpful approach. Blood levels of diazepam and desmethyldiazepam determined by RIA and GLC after extraction are in satisfactory agreement.

Feto-maternal concentrations of diazepam and W-demethyldiazepam after intra-amniotic diazepam injection

Ten milligrams of diazepam were injected intraamniotically in 8 mothers prior to therapeutic abortion between 12 and 19 weeks. The diazepam concentrations in the maternal plasma were comparable to those found after the same intramuscular diazepam dose to the mother. The concentration of diazepam in the amniotic fluid 12 to 18 hours after the injection was no longer significantly higher than in the maternal plasma. The concentrations of diazepam in the fetal plasma, liver and brain were comparable to the concentrations resulting from a 10 mg intramuscular diazepam dose to the mother about 2 hours before legal abortion. The feto-maternal ratio of diazepam was of same magnitude as after the intramuscular application to the mother. The results indicate that the disappearance of diazepam from the amniotic fluid in this stage of pregnancy occurs extraplacentally, through the mambranes into the uterine circulation. In the treatment of a fetus with drugs having properties similar to diazepam, intra-amniotic administration is no better than intramuscular administration to the mother.