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The repeated dose liver micronucleus (RDLMN) assay using young adult rats has the potential to detect genotoxic hepatocarcinogens that can be integrated into a general toxicity study. The assay methods were thoroughly validated by 19 Japanese facilities. Methapyrilene hydrochloride (MP), known to be a non-genotoxic hepatocarcinogen, was examined in the present study. MP was dosed orally at 10, 30 and 100mg/kg/day to 6-week-old male Crl:CD (SD) rats daily for 14 days. Treatment with MP resulted in an increase in micronucleated hepatocytes (MNHEPs) with a dosage of only 100mg/kg/day. At this dose level, cytotoxicity followed by regenerative cell growth was noted in the liver. These findings suggest that MP may induce clastogenic effects indirectly on the liver or hepatotoxicity of MP followed by regeneration may cause increase in spontaneous incidence of MNHEPs., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Methylmethaqualone is a sedative designer drug created by adding a methyl group to the 3-phenyl ring of methaqualone, and is at present not subject to restrictive regulation in many countries. To our knowledge, no case of methylmethaqualone abuse has been published to date in the scientific literature, and the only sources of information are users' reports on Web discussion forums and data from preclinical animal studies. We report a case of oral methylmethaqualone abuse confirmed by liquid chromatography tandem mass spectrometry in a 24-year-old previously healthy Caucasian male. Observed symptoms and signs such as central nervous system depression alternating with excitation, psychomotor agitation, muscle hyperactivity, and tachycardia were compatible with methaqualone-induced adverse effects. Except for the mild tachycardia (115 beats/min), other vital signs were normal: blood pressure 134/89 mmHg, body temperature 36.2°C (97.16°F), and peripheral oxygen saturation 99% while breathing room air. The ECG showed no prolongation of the QT interval and the QRS duration was normal. Laboratory analysis revealed a slight increase in creatine kinase (368 U/L) and alanine aminotransferase (90 U/L) serum concentrations. Blood alcohol concentration was 0.32 g/L. Methylmethaqualone was identified in a serum sample collected on admission which was analyzed by a liquid chromatography tandem mass spectrometry toxicological screening method using turbulent flow online extraction. After a few days the patient ingested the same amount of substance with identical symptoms. Based on the chemical structure and animal data, and according to this case report and users' Web reports, methylmethaqualone appears to have a similar acute toxicity profile to methaqualone, with marked psychomotor stimulation. Symptoms of acute toxicity can be expected to resolve with supportive care.

KR-100 is a newly developed long-lasting insecticide that incorporates cinerins substance, drug-release control substance and synergistic agent following certain procedures under carefully regulated conditions. Tests of the efficacy, toxicity, stability and long-term effect of KR-100 were conducted, and it was show that the insecticide possessed strong and long-lasting effect against mosquitoes, flies and cockroaches but was by no means toxic to human. Morphological study of KR-100 under scanning electron microscope revealed porous membrane form. This insecticide, therefore, can be safely applied with good pesticidal effect.

A case of acute intoxication of both methaqualone and diphenhydramine is reported. The analysis of these compounds was performed by liquid-liquid extraction (Toxi-Lab DPC procedure) followed by gas chromatography/mass spectrometry determination; both substances are contained in the pharmaceutical formulation called Toquilone Compositum (Medichemie, Switzerland).

The substitution of either bromazepam, diazepam, methaqualone, mazindol, nortriptyline or bupropion for pentobarbital, in dependent rats, was assessed using a continuous drug infusion method. Male, Sprague-Dawley rats were made dependent on pentobarbital during 12 days of continuous, intraperitoneal, pentobarbital infusion. On Day 13, pentobarbital was replaced with either saline, vehicle, or one of the drugs of interest and rats were infused for 24 h. On Day 14, all rats were infused, for 24 h, with saline. Changes in both body weight and behavioral indices of withdrawal were assessed during Day 13 and 14. It was observed that bromazepam and methaqualone substituted for pentobarbital in a dose-dependent fashion. Diazepam also substituted in pentobarbital dependent rats but, inexplicably, the low dose of diazepam provided better substitution than did the higher dose. On the other hand, neither mazindol or nortriptyline substituted for pentobarbital and there was a tendency for exacerbation of the withdrawal signs. Finally, it was noted that the low dose of bupropion appeared to decrease the severity of the withdrawal symptoms. The data supports the view that the substitution of compounds for pentobarbital, in dependent rats, is limited to those compounds which, presumably, possess similar mechanisms of action in the CNS.

A series of 4(3H)-quinazolinones structurally related to 2-methyl-3-o-tolyl-4(3H)-quinazolinone (methaqualone, 3) were synthesized and evaluated for anticonvulsant activity. Preliminary screening of these compounds revealed that 2-[2-oxo-2-(4-pyridyl)ethyl]-3-aryl-4(3H)-quinazolinones 6l and 8i, 8k, and 8p-r having a single ortho substituent on the 3-aryl group had the most promising anticonvulsant activity. Compounds 6l and 8i possessing 3-o-tolyl and 3-o-chlorophenyl groups, respectively, showed good protection against MES- and scMet-induced seizures, combined with relatively low neurotoxicity after intraperitoneal administration in mice. They also exhibited low toxicity in tests for determining the mean hypnotic dose (HD50) and the median lethal dose (LD50). Although these compounds were markedly more potent as anticonvulsants when administered orally in mice and rats, they were also more neurotoxic. This neurotoxicity was particularly acute in oral tests with rats, which resulted in marginal protective indices. In drug differentiation tests, compound 6l was ineffective against seizures induced by bicuculline, picrotoxin, and strychnine, while 8i showed some protection against picrotoxin-induced seizures.

The effects of naloxone on narcosis and/or lethality induced by diazepam, lithium, methaqualone and phenobarbital either alone or in combination with ethanol were studied in mice. Interaction toxicities between ethanol and the various psychotropic drugs were dose-dependent and so was the degree of antagonism by naloxone. Treatment with phenobarbital (10 mg/kg) or methaqualone (50 mg/kg) or lithium (4 meq/kg) prolonged the narcosis induced by ethanol (5 g/kg) by 45, 269 and 107% respectively. Naloxone (10 mg/kg) shortened the ethanol (5 g/kg) induced narcosis by 38%. Naloxone (10 mg/kg) also shortened narcosis induced by ethanol (5 g/kg) in combination with phenobarbital (10 mg/kg) or methaqualone (50 mg/kg) or lithium (2meq/kg) by 31, 12 and 38% respectively. At 10 mg/kg of naloxone, the LD50 due to methaqualone was increased from 240 mg/kg to 416 mg/kg, and the LD50 due to ethanol was increased from 9.2 g/kg to 10.8 g/kg. Multiple injections of naloxone significantly (p less than 0.01) protected against the lethality of phenobarbital but not that of lithium. These findings provide further evidence of naloxone antagonism towards various CNS depressants.

1. The effects of acute and chronic treatment of methaqualone on ethanol preference, the rate of disappearance of ethanol and on toxicity were studied in mice and rats. 2. Acute treatment with methaqualone showed a dose-dependent suppression in the voluntary intake of ethanol in C57Bl/6J mice in rats. No significant change in ethanol intake was observed during chronic methaqualone treatment and withdrawal. 3. Methaqualone pretreatment significantly (P less than 0.005) delayed the disappearance of ethanol in the blood and brain over a period of 50 and 200 min after a loading dose of 2.0 g/kg, i.p., of ethanol. 4. Methaqualone pretreatment at doses of 140 and 200 mg/kg significantly increased ethanol toxicity by 11% and 28%, respectively. Co-administration of ethanol using 6.0, 7.0 and 8.0 g/kg also reduced the LD50 of methaqualone by 19%, 24% and 40%, respectively. 5. Chronic administration with ethanol decreased the toxicity due to methaqualone. Potentiation of ethanol toxicity by methaqualone may be of clinical importance in view of the narrow range of safety margin of ethanol.

Patients from a polydrug abuse treatment program were titrated with either secobarbital or methaqualone, their primary drug of abuse, to a state of mild intoxication, consisting of lateral and vertical nystagmus, ataxia, slurred speech, and drownsiness. The mean dose required to produce each sign was compared to that determined in a similarly treated control group. Tolerance to secobarbital was more easily demonstrated than tolerance to methaqualone, and nystagmus was the least sensitive indicator of patient tolerance. The individual signs were also cumulated into a graded rating scale of central nervous system depression which would be related to the dose administered. Tolerence was easily demonstrated at the higher stages of toxicity for secobarbital in the overall patient population, but tolerance to methaqualone was only unequivocal in the subjects indicating a relatively high frequency of abuse. Tolerance to methaqualone occurred at the lower stages of toxicity, suggesting that there is a difference between tolerance to secobarbital and tolerance to methaqualone. There was no indication that patients who also abuse alcohol are more tolerant than their patient counterparts. The patients who also had a history of amphetamine abuse, however, were less tolerant than the nonusers of these drugs.

Methaqualone treatment of pregnant rats in doses of 100-200 mg/kg day produces resorption and a series of anomalies whose incidence increases with the dose-level employed.