New approach for barbiturates, phenytoin, methyprylon and glutethimide determination and fragmentation (UHPLC-MS/MS).

Barbiturates which are old pharmaceutical drugs are still widely used in medical treatment of epilepsy and for general anesthesia. To date, more than 2500 different barbituric acid analogs have been synthesized, and 50 of them were introduced into medical use over the last century. Due to their highly addictive properties, pharmaceuticals containing barbiturates are under strict control in many countries. However, by considering the worldwide problem with new psychoactive substances (NPS) the introduction of new designer barbiturate analogs into the dark market might serve a serious public health problem in the near future. For this reason there is an increasing need for application methods for barbiturates monitoring in biological samples. The UHPLC-QqQ-MS/MS method for determination of 15 barbiturates, phenytoin, methyprylon and glutethimide was developed and fully validated. The biological sample volume was reduced to only 50 µL. A simple LLE (pH 3 with ethyl acetate) was successfully applied. The lower LOQ was 10 ng/mL. The method enables differentiation of structural isomers: hexobarbital and cyclobarbital; as well as amobarbital and pentobarbital. Chromatographic separation was achieved with the use of the alkaline mobile phase (pH 9) and Acquity UPLC BEH C18 column. Furthermore, the novel fragmentation mechanism of barbiturates was proposed, which may have a great impact in identification of novel barbiturates analogs introduced to illegal marketplaces. The presented technique has a great potential to be applied in forensic, clinical and veterinary toxicological laboratories, as was evidenced by the positive results of international proficiency tests.

4-Hydroxyglutamate is a novel predictor of pre-eclampsia.

BACKGROUND: Pre-term pre-eclampsia is a major cause of maternal and perinatal morbidity and mortality worldwide. A multi-centre randomized-controlled trial has shown that first-trimester screening followed by treatment of high-risk women with aspirin reduces the risk of pre-term pre-eclampsia. However, the biomarkers currently employed in risk prediction are only weakly associated with the outcome. METHODS: We conducted a case-cohort study within the Pregnancy Outcome Prediction study to analyse untargeted maternal serum metabolomics in samples from 12, 20, 28 and 36 weeks of gestational age (wkGA) in women with pre-eclampsia delivering at term (n = 165) and pre-term (n = 29), plus a random sample of the cohort (n = 325). We used longitudinal linear mixed models to identify candidate metabolites at 20/28 wkGA that differed by term pre-eclampsia status. Candidates were validated using measurements at 36 wkGA in the same women. We then tested the association between the 12-, 20- and 28-wkGA measurements and pre-term pre-eclampsia. We externally validated the association using 24- to 28-wkGA samples from the Born in Bradford study (25 cases and 953 controls). RESULTS: We identified 100 metabolites that differed most at 20/28 wkGA in term pre-eclampsia. Thirty-three of these were validated (P < 0.0005) at 36 wkGA. 4-Hydroxyglutamate and C-glycosyltryptophan were independently predictive at 36 wkGA of term pre-eclampsia. 4-Hydroxyglutamate was also predictive (area under the receiver operating characteristic curve, 95% confidence interval) of pre-term pre-eclampsia at 12 (0.673, 0.558-0.787), 20 (0.731, 0.657-0.806) and 28 wkGA (0.733, 0.627-0.839). The predictive ability of 4-hydroxyglutamate at 12 wkGA was stronger than two existing protein biomarkers, namely PAPP-A (0.567, 0.439-0.695) and placenta growth factor (0.589, 0.463-0.714). Finally, 4-hydroxyglutamate at 24-28 wkGA was positively associated with pre-eclampsia (term or pre-term) among women from the Born in Bradford study. CONCLUSIONS: 4-hydroxyglutamate is a novel biochemical predictor of pre-eclampsia that provides better first-trimester prediction of pre-term disease than currently employed protein biomarkers.

A study of the risk of mental retardation among children of pregnant women who have attempted suicide by means of a drug overdose.

BACKGROUND: The aim of the study was to estimate the effect on the fetal development of high doses of prescription drugs taken as a suicide attempt during pregnancy. METHODS: Pregnant women were identified among self-poisoned females in the toxicological inpatient clinic in Budapest between 1960 and 1993. Congenital abnormalities, intrauterine development based on birth weight and post-conceptional age, mental retardation, cognitive-behavioral status were compared in exposed children born to mothers who had attempted suicide by means of a drug overdose during pregnancy with their siblings, born either before or after the affected pregnancy, as sib controls. RESULTS: Of a total of 1 044 pregnant women, 74 used the combination of amobarbital, glutethimide and promethazine (Tardyl®, one of the most popular drugs for treatment of insomnia in Hungary) for suicide attempt. Of these 74 women, 27 delivered live-born babies. The mean dose of Tardyl® used for suicide attempts was 24 times the usually prescribed clinical dose. The rate of congenital abnormalities and intrauterine retardation was not higher in exposed children than in their sib controls. However, of the 27 exposed children, eight (29.6%) were mentally retarded (X²1=79.7, p= Sig) while mental retardation did not occur among 46 sib controls. These exposed children were born to mothers who attempted suicide with Tardyl® between the 14th and 20th post-conceptional weeks. The components of Tardyl® used separately for a suicide attempt during pregnancy were not associated with a higher risk of mental retardation. Therefore the high doses of Tardyl® associated with the high risk for mental retardation may be due to the interaction of its three drug components. CONCLUSIONS: The findings of the study showed that the high doses of a drug containing three components may be associated with a significantly increased risk for mental retardation without any structural defects, whereas each of these three component drugs taken alone was not associated with this adverse effect.

Determination of phenformin hydrochloride using molecular imprinting technology coupled with flow-injection chemiluminescence.

A novel method was developed using molecular imprinting technology (MIT) coupled with flow-injection chemiluminescence (FI-CL) for highly sensitive detection of phenformin hydrochloride (PH). The phenformin imprinted polymer was synthesized with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. Newly synthesized molecularly imprinted polymer (MIP) particles were packed into a column as a selective recognition element for determination of PH. A CL method for the determination of PH was developed based on the CL reaction of PH with N-bromosuccinimide sensitized by eosin Y in basic media. The optimization of detection conditions was investigated. The CL intensity responded linearly to the concentration of PH in the range 0.09-2.0 µg/mL, with a correlation coefficient of 0.9920. The detection limit was 0.031 µg/mL. The relative standard deviation for the determination of 1.0 µg/mL PH solution was 1.0% (n = 11). The method was applied to the determination of PH in urine samples, with satisfactory results.

A study of the effects of large doses of glutethimide that were used for self-poisoning during pregnancy on human fetuses.

Animal investigations showed some embryolethal and teratogenic effects of glutethimide, a piperidindion derivative non-barbital hypnotic drug. Thus, the objective of this study was to evaluate the effects of very large doses of glutethimide that were used for a suicide attempt during pregnancy on the embryo-fetal development of exposed children. Self-poisoned pregnant women were identified from the population of female patients of the Department of Toxicology Internal Medicine, Korányi Hospital, Budapest who had been admitted from the 3 million people of Budapest and its surrounding region. The rates of congenital abnormalities, intrauterine fetal development (based on birth weight and pregnancy age at delivery) and cognitive-behavioral status of exposed children born to mothers who attempted suicide with glutethimide alone or in combination with other drugs during pregnancy were compared with their sib controls. Of 1044 pregnant women with self-poisoning during pregnancy between 1960 and 1993, 33 used glutethimide for a suicide attempt sixteen of these women delivered live-born infants. The dose of glutethimide ranged between 1000 and 15,000 mg with a mean of 4234 mg. Of the 16 exposed children, five were male and 11 were female. Three exposed children were affected with congenital abnormalities (atrial septal defect type II, pectus carinatum, fetal alcohol syndrome). Of their 16 matched unexposed sib pairs, two had congenital abnormalities. The mean birth weight of the exposed children was somewhat larger due to somewhat longer pregnancy age at delivery. Cognitive status and behavioral scale of the exposed children did not indicate a fetotoxic (including neurotoxic) effect of large doses of glutethimide. Very large doses of glutethimide used for a suicide attempt by 16 pregnant women did not produce teratogenic or fetotoxic (including neurotoxic) effects in their children.

Automated screening platform with isochronal-parallel analysis and conditioning for rapid method development of chiral separations.

An automated chiral separation-screening platform was developed, allowing separation analysis on one column while another column is simultaneously equilibrated with a different mobile phase (MP). The platform can be set up from usual HPLC components at moderate cost and it considerably speeds up the screening process, allowing numerous chromatographic conditions to be tested within a short period of time and leading to a significant gain in time and productivity in preparative separations.

Aminoglutethimide-induced protein free radical formation on myeloperoxidase: a potential mechanism of agranulocytosis.

Aminoglutethimide (AG) is a first-generation aromatase inhibitor used for estrogen-dependent breast cancer. Unfortunately, its use has also been associated with agranulocytosis. We have investigated the metabolism of AG by myeloperoxidase (MPO) and the formation of an MPO protein free radical. We hypothesized that AG oxidation by MPO/H2O2 would produce an AG cation radical that, in the absence of a biochemical reductant, would lead to the oxidation of MPO. We utilized a novel anti-DMPO antibody to detect DMPO (5,5-dimethyl-1-pyrroline N-oxide) covalently bound to protein, which forms only by the reaction of DMPO with a protein free radical. We found that AG metabolism by MPO/H2O2 induced the formation of DMPO-MPO, which was inhibited by MPO inhibitors and ascorbate. Glutethimide, a congener of AG that lacks the aromatic amine, did not cause DMPO-MPO formation, indicating the necessity of oxidation of the aniline moiety in AG. When analyzed by electron spin resonance spectroscopy, we detected a phenyl radical adduct, derived from AG, which may be involved in the free radical formation on MPO. Furthermore, we also found protein-DMPO adducts in MPO-containing, intact human promyelocytic leukemia cells (HL-60). MPO was affinity-purified from HL-60 cells treated with AG/H2O2 and was found to contain DMPO. These findings were also supported by the detection of protein free radicals with electron spin resonance in the cellular cytosolic lysate. The formation of an MPO protein free radical is believed to be mediated by one of two free radical drug metabolites of AG, one of which was characterized by spin trapping with 2-methyl-2-nitrosopropane. These results are the first demonstration of MPO free-radical detection by the anti-DMPO antibody that results from drug oxidation. We propose that drug-dependent free radical formation on MPO may play a role in the origin of agranulocytosis.

Haem repression of the housekeeping 5-aminolaevulinic acid synthase gene in the hepatoma cell line LMH.

Haem is essential for the health and function of nearly all cells. 5-Aminolaevulinic acid synthase-1 (ALAS-1) catalyses the first and rate-controlling step of haem biosynthesis. ALAS-1 is repressed by haem and is induced strongly by lipophilic drugs that also induce CYP (cytochrome P450) proteins. We investigated the effects on the avian ALAS-1 gene promoter of a phenobarbital-like chemical, Glut (glutethimide), and a haem synthesis inhibitor, DHA (4,6-dioxoheptanoic acid), using a reporter gene assay in transiently transfected LMH (Leghorn male hepatoma) hepatoma cells. A 9.1 kb cALAS-1 (chicken ALAS-1) promoter-luciferase-reporter construct, was poorly induced by Glut and not by DHA alone, but was synergistically induced by the combination. In contrast, a 3.5 kb promoter ALAS-1 construct was induced by Glut alone, without any further effect of DHA. In addition, exogenous haem (20 microM) repressed the basal and Glut- and DHA-induced activity of luciferase reporter constructs containing 9.1 and 6.3 kb of ALAS-1 5'-flanking region but not the construct containing the first 3.5 kb of promoter sequence. This effect of haem was subsequently shown to be dependent on the -6.3 to -3.5 kb region of the 5'-flanking region of cALAS-1 and requires the native orientation of the region. Two deletion constructs of this approx. 2.8 kb haem-repressive region (1.7 and 1.1 kb constructs) retained haem-dependent repression of basal and drug inductions, suggesting that more than one cis-acting elements are responsible for this haem-dependent repression of ALAS-1. These results demonstrate that there are regulatory regions in the 5'-flanking region of the cALAS-1 gene that respond to haem and provide a basis for further investigations of the molecular mechanisms by which haem down-regulates expression of the ALAS-1 gene.

Generic capillary electrophoresis conditions for chiral assay in early pharmaceutical development.

Generic capillary electrophoresis (CE) conditions have been implemented for chiral separations in early pharmaceutical development. The chiral CE separations of several pharmaceutical samples at different stages of development, i.e., discovery, process chemistry, and investigative new drug application, have been obtained using sulfated beta-cyclodextrin (CD). Several sulfated beta-CDs have been screened to select an appropriate enantioselective agent. The use of a generic CE method allows for a convenient and rapid chiral recognition of different weak bases, with minimal or no method development. CE using sulfated beta-CD for the chiral separation of N-benzoyl methyl piperazine has been validated for linearity, precision, accuracy, limits of detection and quantitation (LOD, LOQ). Although less sensitive than a specific liquid chromatography method using a Chiralpak AD column, the overall performance of the chiral CE method was found comparable. Validation data demonstrate that a LOD of 0.1%, sufficient to fulfill regulatory requirements, is achievable by chiral CE.

Enantiomeric separation of glutethimide derivatives using a Ceramospher RU-2 column.

The enantiomeric resolution of p-acetylaminoglutethimide and p-nitroglutethimide was achieved on a Ceramospher RU-2 column using methanol as the mobile phase. The flow rates of the mobile phase were 1.0 and 0.5 mL/min for p-acetylaminoglutethimide and p-nitroglutethimide, respectively, with UV detection at 254 nm. The values of alpha of the resolved enantiomers of p-acetylaminoglutethimide and p-nitroglutethimide were 1.63 and 1.24 while the values of Rs were 1.44 and 0.86 respectively. The possible chiral mechanism was the formation of transient diastereomeric intermediates between the enantiomers and the chiral selector (1,10-phenanthroline) ruthenium II complex which was stabilized by pi-pi interactions.

The study of codeine-gluthetimide pharmacokinetic interaction in rats.

A high-performance liquid chromatographic (HPLC) assay with native fluorescence detection was developed for the simultaneous quantification of codeine and its two metabolites, morphine and morphine-3-glucuronide (M-3-G), in rat plasma. Solid-phase extraction was used to separate codeine and its metabolites from plasma constituents. Extraction efficiencies of codeine, morphine and M-3-G from rat plasma samples were 97, 92 and 93%, respectively. The chromatographic separation was performed using a reversed-phase C18 column and an elution gradient at ambient temperature. Using native fluorescence detection (excitation at 245 nm and emission at 345 nm), the detection limits of 50 ng/ml for morphine, 25 ng/ml for codeine and 20 ng/ml for M-3-G were obtained. The method had good precision, accuracy and linearity, and was applied to the study of glutethimide's influence on codeine metabolism in rat, following single doses of codeine-glutethimide association. The results confirmed the fact that glutethimide was responsible for a significant increase of morphine plasma levels and for their maintenance in time, concomitant with a significant decrease of M-3-G plasma levels, explained by the inhibition of morphine glucuronidation. In conclusion, glutethimide potentiates and prolongs the analgesic effect of codeine by a pharmacokinetic mechanism.

[Suicidal attempts with old (currently unused) drug]. / Zatrucie samobójcze lekiem z przeszlosci.

Suicidal attempt with old (currently unused) drug is described. The suicidal attempts are usually performed with the use of contemporary pharmacotherapeutics. In the report a case of suicidal attempt with old drug Tardyl is presented. Tardyl (Glutethimid) was prescribed to the patient and has been stored for 20 years. The patient was previously treated for depression and many suicidal attempts. In the course of intoxication: balance disturbances, psychomotor retardation, changes in consciousness with temporary excitation were observed. The concentration of glutethimid in the urine was 1.1 mg% and 0.5 mg% in the blood. Patient was treated according to the general rules of intensive care. After 4 days of therapy the patient improved and was transferred to psychiatric unit in Koscian.

Enantioseparation of glutethimide and its 5-OH-metabolite in capillary electrophoresis and study of selector-selectand interactions using one-dimensional rotating frame nuclear Overhauser and exchange spectroscopy.

Enantioseparation of glutethimide (GT) and its 5-hydroxy metabolite (5-OH-GT) has been studied with several charged cyclodextrin (CD) derivatives. The emphasis was made on the enantiomer migration order of GT and simultaneous enantioseparation of GT and 5-OH-GT. The possible structural differences of GT complexes with three different single isomer charged CD derivatives were studied using one-dimensional rotating frame nuclear Overhauser and exchange spectroscopy (1-D ROESY).

Isolation of regioisomers of N-alkylprotoporphyrin IX from chick embryo liver after treatment with porphyrinogenic xenobiotics.

Several porphyrinogenic xenobiotics cause mechanism-based inactivation of cytochrome P450 (P450) isozymes with concomitant formation of a mixture of four N-alkylprotoporphyrin IX (N-alkylPP) regioisomers, which have ferrochelatase inhibitory properties. To isolate the four regioisomers of N-methylprotoporphyrin IX (N-methylPP), 3,5-diethoxycarbonyl, 1-4-dihydro-2,4,6-trimethylpyridine (DDC) was administered to untreated, beta-naphthoflavone-, phenobarbital-, and glutethimide-pretreated 18-day-old chick embryos. Separation of the N-methylPP regioisomers by high pressure liquid chromatography (HPLC) revealed no marked difference in the regioisomer pattern among the different treatments. After administration of griseofulvin, allylisopropylacetamide (AIA), or 1-[4-(3-acetyl-2,4,6-triemethylphenyl)-2,6-cyclohexanedionyl]-O-ethyl propionaldehyde oxime (ATMP) to untreated and glutethimide-pretreated 18-day-old chick embryos, an N-alkylPP was isolated after AIA administration only. This finding strengthened previous reports of the species specificity of N-alkylPP formation with griseofulvin and ATMP. A series of dihydropyridines, namely 4-ethylDDC, 4-hexylDDC, and 4-isobutylDDC were administered to untreated and glutethimide-pretreated 18-day-old chick embryos and hepatic N-alkylPPs were isolated and separated by HPLC into regioisomers. The regioisomer patterns obtained did not support a previous proposal of masked regions above both rings B and C in the heme moieties of the P450 isozymes responsible for N-alkylPP formation. However, the data support the hypothesis of a partially masked region above ring B alone. The regioisomer patterns were in agreement with results previously obtained in rats showing that the percentage of Nc and (or) ND regioisomers in the regioisomer mixture increases as the length and bulk of the 4-alkyl substituent of a DDC analogue increase. Differences in the regioselectivity of heme N-alkylation may be due to intrinsic chemical features of DDC analogues themselves or to differences in the P450 isozymes inactivated.

Conservation of signaling pathways of xenobiotic-sensing orphan nuclear receptors, chicken xenobiotic receptor, constitutive androstane receptor, and pregnane X receptor, from birds to humans.

Chicken xenobiotic receptor, pregnane X receptor, and constitutive androstane receptor are orphan nuclear receptors that have recently been discovered to regulate drug- and steroid-mediated induction of hepatic cytochromes P450 (CYP). This induction is part of an adaptive response involving numerous genes to exposure to drugs and chemicals and has major clinical and toxicological implications. Here we report experiments in the chicken hepatoma cell line LMH that suggest evolutionary conservation of the signaling pathways triggered by pregnane X receptor, constitutive androstane receptor, and chicken xenobiotic receptor. Thus, the phenobarbital-inducible enhancer units of the mouse Cyp2b10, rat CYP2B2, and human CYP2B6 genes were activated in reporter gene assays by the same compounds that activate the chicken CYP2H1 phenobarbital-inducible enhancer units. Chicken xenobiotic receptor, pregnane X receptor, and constitutive androstane receptor all bound to the CYP2H1 phenobarbital-inducible enhancer units in gel-shift experiments. In CV-1 cell transactivation assays, mammalian pregnane X receptors activate the chicken phenobarbital-inducible enhancer units to the same extent as does chicken xenobiotic receptor, each receptor maintaining its species-specific ligand spectrum. To assess the reported role of protein phosphorylation in drug-mediated induction, we treated LMH cells with okadaic acid and observed increased mRNA of delta-aminolevulinate synthase and CYP2H1 whereas expression of CYP3A37 was decreased. The effects of okadaic acid and other modifiers of protein phosphorylation in LMH cells are comparable to those seen on CYP2Bs and CYP3As in mammalian primary hepatocyte cultures. These results indicate that closely related nuclear receptors, transcription factors, and signaling pathways are mediating the transcriptional activation of multiple genes by xenobiotics in chicken, rodents, and man.

Influence of glutethimide on rat brain mononucleotides by sub-chronic codeine treatment.

It was investigated the in vivo effect of glutethimide on the intracellular neuroadaptation characteristic for m-opioid receptor tolerance induced by chronic codeine treatment and reflected by increased levels of adenylyl cyclase (AC) and cAMP-dependent protein kinase (PKA). AC activity was appreciated by cyclic-AMP (cAMP) formation, the levels of adenine and guanine nucleotides in brain extracts being assayed using a high performance liquid chromatographic method. The concomitant chronic administration of codeine and glutethimide resulted in a pronounced and long-lasting energetic depletion of the neurons, consistent with the high risk of overdose, and increase of cAMP's stable metabolite, 5'-AMP. This increase is persistent even after withdrawal and suggests an interference with the adenylyl cyclase system involved in the development of tolerance of opioid receptor and in relapse and provides a possible explanation of addiction and fast increase of doses observed in humans abusing this combination.

Heme biosynthesis in a chicken hepatoma cell line (LMH): comparison with primary chick embryo liver cells (CELC).

5-Aminolevulinic acid synthase (ALA synthase), the rate-controlling enzyme of hepatic heme biosynthesis, is feed-back repressed by heme. In the liver, chemicals such as barbiturates markedly induce ALA synthase, especially in the presence of partial defects of heme biosynthesis. The inducibility and regulation of ALA synthase have been investigated using a variety of models, including intact animals and liver cell culture systems. A widely used model that closely approximates what occurs in vivo and in humans is that of primary cultures of chick embryo liver cells (CELCs). However, CELCs have some limitations: the cells obtained are somewhat heterogeneous; isolation and culture must be repeated every week resulting in weekly variations; and cells are short-lived limiting the feasibility of time-course and transfection studies. The aim of this study was to determine if LMH cells, a chick hepatoma cell line, are a good model comparable to that of CELCs. In both cells similar patterns of response of, ALA synthase activities and mRNA levels, and of porphyrin accumulation were obtained following treatments known to affect heme biosynthesis. Similarly, heme repressed ALA synthase mRNA levels in both cell types and ALA synthase activities in LMH cells. We conclude that LMH cells are a useful model for the study of hepatic heme biosynthesis and regulation of ALA synthase.