Reproduction study of 4-ethoxy-2-methyl-5-morpholino-3(2H)-pyridazinone (M73101) in rats (II). Administration of M73101 during the period of major organogenesis (author's transl)]

Pregnant female rats were given orally M73101 (0,100,250 and 600 mg/kg) or aspirin (225 mg/kg) on gestational days 7 to 17. About two-thirds of treated females in each group were sacrificed at day 21 of pregnancy and their fetuses were examined for abnormalities. The remaining females were allowed to deliver spontaneously in order to observe postnatal development of their offspring. The results were summarized as follows: 1. No significant effects of M73101 on number of the corpora lutea, litter size, fetal mortality, fetal weight or sex ratio were observed, but aspirin exhibited the intrauterine deaths and growth retardation in fetuses. 2. No external, internal or skeletal malformations attributable to M73101 were seen in fetuses, although aspirin caused malformations of various organ systems. 3. No apparent effects of M73101 on F1 generation were observed on postnatal development including emotionality, learning ability and reproductive performance. There were no adverse influences of M73101 on postnatal development of F2 generation. Aspirin, however, showed adverse effects on postnatal survival, growth, emotionality and mating performance of F1 generation.     

Pharmacological studies of 4-ethoxy-2-methyl-5-morpholino-3(2H)-pyridazinone (M73101). (4). Enzyme induction (author's transl)]

The effect of M7310U, a new non-steroidal analgesic anti-inflammatory agent, on liver microsomal drug-metabolizing enzymes was investigated. Rats were treated orally with M73101 (100, 200, 500 mg/kg), henylbutazone (PZ, 200 mg/kg), aminopyrine (AM, 100 mg/kg) or phenobarbital sodium (PB, 100 mg/kg) once daily for 2 weeks and then were observed for 2 weeks during which treatment was not given. On treatment with M73101, PZ, AM and PB, the liver enlarged but was restored to normal 1 week after the last administration. The rate of increase in the case of M73101 was lower than that seen with the reference compounds. M73101 markedly increased the content of microsomal protein, cytochrome P-450 or b5 and NADPH cytochrome C reductase, aniline hydroxylase and AM demethylase activity, but these increments returned to the normal level 1 week after the last administration. The serum concentration of M73101 after repeated administration (200 mg/kg, p.o.) for 1 week was lower than that after a single administration. Furthermore, M73101 increased Vmax for both aniline hydroxylase and AM demethylase, whereas it increased Km only for aniline hydroxylase. M73101 did not enhance the lipid peroxidation. Our observations suggest that the enlargement of rat liver seen with M73101 was due to the induction of drug-metabolizing enzymes and that this agent can probably be classified as a phenobarbital-type inducer.     

Chronic toxicity test of 4-ethoxy-2-methyl-5-morpholino-3(2H)-pyridazinone (M73101) in beagle dogs (author's transl)]

Male and female dogs, aged 17--21 months, were administered orall M 73101 (0, 60, 120 and 240 mg/kg/day), a new analgesic and antiinflammatory drug, for 27 weeks, and following recovery test was carried out for 5 weeks. Dead animals were not found throughout the experimental period. Body weight gain, and food and water consumption were not affected due to M 73101 administration. Except for a slight increase of vomitting in the highest dose, there were no abnormal symptoms. Biochemical examination showed the slight increase in serum alkaline phosphatase activity and free cholesterol level. Pathological examination revealed a dose-dependent increase of liver weight and hypertrophy of hepatocytes due to proliferation of smooth endoplasmic reticulum. In addition, mitochondria became irregularly large in the highest dose. There were no abnormal findings in the gastro-intestinal tracts except for an erosion of gastric mucosa, which was noted in a female dog treated 240 mg/kg/day of M 73101. From these results, it was suggested that the maximum non-toxic dose was 60 mg/kg/day or less, and the greatest safety dose was 120 mg/kg/day in beagle dogs.     

Pharmacological studies of 4-ethoxy-2-methyl-5-morpholino-3(2H)-pyridazinone (M73101). (2). Anti-inflammatory activity (author's transl)]

The anti-inflammatory activity and the mode of action of M73101, a new non-steroid analgesic anti-inflammatory agent, were investigated in experimental animals and compared with those of reference drugs. M73101 inhibited the increase in vascular permeability induced by acetic acid and its activity was more potent than that of phenylbutazone. M73101 showed a marked inhibitory effect against rat paw edema induced by various phlogistic agents (carrageenin, dextran, histamine, serotonin and bradykinin) and the activities were equal to or more potent than those of aminopyrine, mepirizole and tiaramide HCl. M73101 also inhibited the edema induced by mustard, scalding and anti-rat rabbit serum in rats. In addition, the anti-edematous effect of M73101 on carrageenin-induced rat paw edema was not influenced by spinalectomy or adrenalectomy, indicating that the anti-inflammatory action of M73101 was not mediated by the central nervous system and the adrenals. Local and oral administration of M73101 inhibited significantly the leucocyte migration into the fluid of CMC pouch in rats and the activity was more potent than phenylbutazone, suggesting that the anti-inflammatory effect of M73101 was due to the direct action at the inflamed site. On the other hand, M73101 did not show any marked activities on the experimental chronic inflammatory models. From these results, it is suggested that M73101 may be useful for clinical application as a basic analgesic, anti-inflammatory drug with remarkable anti-inflammatory activity in acute and subacute cases. The mechanism of the anti-inflammatory action of M73101 probably involves inhibition of an increase in vascular permeability and leucocyte migration.     

Teratological study of 4-ethoxy-2-methyl 5-morpholino-3(2H)-pyridazinone (M73101) in mice and rats (author's transl)]

M73101 was given orally to pregnant mice (0, 100, 400 and 800 mg/kg/day) and rats (0, 100, 300 and 600mg/kg/day) during the major organogenesis to assess the influences of prenatal and postnatal development of progeny. There were no apparent effects of M73101 on litter size, fetal mortality or sex ratio in both species, although slight decrease in body weight occurred in fetuses of mice and rats exposed to the largest dose. No external, internal or skeletal malformations attributable to M73101 were observed in mouse and rat fetuses. No apparent influences of M73101 on postnatal development of mouse or rat offspring were seen.     

Pharmacological studies of 4-ethoxy-2-methyl-5-morpholino-3(2H)-pyridazinone (M73101). (3). General pharmacological actions (author's transl)]

General pharmacological actions of M73101, a new non-steroidal analgesic anti-inflammatory drug were investigated in mice, rats, guinea pigs, rabbits, cats and dogs. Intravenous administration of M73101 produced a slight transient fall in blood pressure, an increase in heart rate and a respiratory stimulation, but no remarkable change in the electrocardiogram. The contraction induced by epinephrine in the isolated ear vessels of rabbits relaxed by M73101. In the isolated trachea of guinea pigs, M73101 relaxed the contraction induced by histamine. Furthermore, M73101 inhibited the bronchoconstriction by histamine but not by bradykinin in guinea pigs. These properties of M73101 on the tracheal smooth muscle were similar to those seen with aminopyrine but different from those seen with aspirin which inhibited only the contraction by bradykinin in vivo, suggesting that M73101 is a compound with properties similar to basic non-steroidal anti-inflammatory drugs. M73101 inhibited the intestinal propulsion in mice and also the gastrointestinal movement in rats and dogs. Moreover, M73101 showed a spasmolytic activity on the isolated ileum of guinea pigs, but such was not due to any specific antagonistic action on the chemical mediators. On the other hand, M73101 had no effect on the isolated uterus and vas deferens of rats. M73101, unlike aminopyrine and phenylbutazone, slightly increased urine volume and electrolytes excretion in rats, indicating that this compound probably does not produced edema. M73101 showed no significant pharmacological activities on the blood sugar level, blood coagulation, platelet aggregation, methemoglobin formation and local irritation.     

Pharmacological studies of 4-ethoxy-2-methyl-5-morpholino-3(2H)-pyridazinone (M73101). (5) Action of M73101 on the central nervous system (author's transl)

M73101 decreased spontaneous locomotor activity in both mice and rats and prolonged sleeping time induced by hexobarbital in mice. There was no evidence of cataleptogenic action, anti-tremorine action and antagonistic effect on reserpine-induced hypothermia in mice. M73101 did not inhibit convulsions induced by maximal electroshock and pentylenetetrazol but slightly inhibited the convulsion induced by strychnine in mice. Moreover, M73101 depressed only the monosynaptic action potential in intact and spinal cats, indicating that this compound exerts an inhibitory action on spinal function. On the EEG of rabbits, M73101 produced an arousal pattern in the spontaneous EEG and inhibited the recruiting response, but had no marked influence on the EEG arousal response, augmenting response and hippocampal afterdischarge. The arousal pattern in the spontaneous EEG induced by M73101 and the inhibitory action of this compound on the recruiting response were absent in the cerveau isolé preparation of the rabbit, indicating that M73101 may stimulate the brainstem reticular formation and that the inhibition of recruiting response may be related to the stimulatory effect. These properties of M73101 on the central nervous system are similar to those seen with aminopyrine though the potency was weaker. M73101 like aminopyrine showed no marked activity on the motor function.     

Pharmacological investigations of 4-ethoxy-2-methyl-5-morpholino-3(2H)-pyridazinone (M 73101), a new analgesic and anti-inflammatory drug

Analgesic, anti-inflammatory and other related actions of 4-ethoxy-2-methyl-5-morpholino-3(2H)-pyridazinone (M73101) were investigated in experimental animals, and the following results were obtained: Analgesic activity of M73101 was more potent than that of other anti-inflammatory drugs except for aminopyrine in phenylquinone test in mice. M73101 showed the most potent analgesic activity among the drugs tested in Randall-Selitto test in rats. The mode of analgesic action of M73101 resembled that of aminopyrine. M73101 possessed potent inhibitory activities on acute inflammatory edema and suppressed the permeability of capillary vessels. M73101 inhibited histamine release from isolated rat mast cells (in vitro) and rat skin (in vivo) by the condensation product of N-methyl-homoanisylamine formaldehyde (compound 48/80), and leucocyte emigration in carrageenin rat pleurisy. M73101 was much less active than phenylbutazone and other anti-inflammatory drugs in causing gastric lesion. Considering from therapeutic index, M73101 was found to be much superior to mepirizole, tiaramide, benzydamine, phenylbutazone and acetylsalicylic acid.     

Photolysis of 3-methyl- and 3-phenyl-4-amino-2-methyl-1-phenyl-3-pyrazolin-5-one (author's transl)

Photolysis of 3-Methyl- and 3-Phenyl-4-amino-2-methyl-phenyl-3-pyrazolin-5-one During the irradiation of aqueous solutions of 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one ( 1d ) besides the compounds 2 and 3 characteristic photolysis products of pyrazolones (Type I), the compound 12 is obtained, which was formed from two molecules of 1d . 4-Amino-2-methyl-1,3-diphenyl-3-pyrazolin-5-one, however isomerises to 8, which upon further irradiation fragments into several components two of them being N-phenyloxamide and N,N′-diphenyloxamide.     

In vitro properties of 5-(benzylsulfonyl)-4-bromo-2-methyl-3(2H)-pyridazinone: a novel permeability transition pore inhibitor

Despite the increasing implication of the permeability transition pore (PTP) in the pathophysiology of neurodegenerative diseases, few selective PTP inhibitors have been reported so far. Here, we evaluate the pharmacological properties of a novel PTP inhibitor, BBMP (5-(benzylsulfonyl)-4-bromo-2-methyl-3(2H)-pyridazinone). This drug was discovered from the screening of a compound library against the PTP using a functional assay with isolated mitochondria. Similarly to cyclosporin A, the drug prevented Ca2+-induced permeability transition and mitochondrial depolarization. BBMP appeared more potent that minocycline in both swelling and membrane potential assays displaying pIC50 values of 5.5+/-0.1 and 5.6+/-0.0, respectively. Unlike minocycline, BBMP dose-dependently prevented DNA fragmentation induced by KCl 25/5 mM shift and serum deprivation in cerebellar granule neurons with a pIC50 of 5.7+/-0.6. The inhibition of PTP-mediated cytochrome c release observed in isolated mitochondria at 10 and 100 microM may explain its neuroprotective properties in vitro. These data suggest that the mitochondrial PTP is potentially involved in neuronal cell death and that PTP inhibitors, like BBMP, may possess a therapeutic potential in neurodegenerative disorders.     

Preparation of Di3H(9,10)-hydroergot Alkaloids (author's transl)]

In katalytic hydrogenation of native ergot alkaloids with tritium a specific addition of 3H in 9,10 position of the molecules results. The most favourable technique is described in detail on the example of ergotamine/dihydroergotamine.     

4-Hydroxy-5-hydroxyimino-7-methyl-5H-pyrano (2,3-b) pyridine 8-oxide (author's transl)

4-Hydroxy-5-hydroxyimino-7-methyl-5H-pyrano[2,3-b]pyridine 8-Oxide In the course of studies on the reaction between dehydroacetic acid ( 1 ), N,N-dimethylformamide dimethyl acetal and hydroxylamine, a new two-step synthesis of a pyranopyridine with the structure of a vinylogous hydroxamic acid was discovered. The isomeric structures 5a - 8b , derived from the empirical formula C₉H₈N₂O₄ are discussed. The existence of 5a in solution is indicated by the spectral data (ms, ir, nmr).