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Biomedical subjects

H Kamimura

Publications and source records attributed to H Kamimura.

At least 73 records · Page 4Linked to original sources
PubMed1984

Pharmacokinetics of amosulalol, an alpha, beta-adrenoceptor blocker, in rats, dogs and monkeys.

The pharmacokinetics of an alpha, beta-adrenoceptor blocker, amosulalol hydrochloride, were studied after i.v. and oral administration to rats, dogs and monkeys. After an i.v. dose (1 mg/kg), the plasma concentration-time curve fitted a two-compartment open model with terminal half-lives of 2.5 h in rats, 2.1 h in dogs and 1.8 h in monkeys. The order of plasma clearances for amosulalol was: rats greater than dogs greater than monkeys. After oral administration, the maximum plasma concentration was obtained at 0.5-1 h in rats (10-100 mg/kg) and dogs (3-30 mg/kg), and at 1.7-2.7 h in monkeys (3-10 mg/kg). A linear relationship between the area under the plasma concentration-time curve and dose administered was obtained for all three species. The systemic availabilities of the drug in rats, dogs and monkeys were 22-31%, 51-59% and 57-66%, respectively. After repeated oral administration (10 mg/kg) to dogs for 15 days, the pharmacokinetic parameters did not differ significantly from those on the first day.

Administration, Oral↗
PubMed1984

Disposition and metabolism of amosulalol hydrochloride, a new combined alpha- and beta-adrenoceptor blocking agent, in rats, dogs and monkeys.

The disposition and metabolism of amosulalol hydrochloride, a combined alpha- and beta-adrenoceptor blocking agent, were studied in rats, dogs and monkeys. After oral administration of [14C]amosulalol hydrochloride, the plasma concentration of radioactivity reached a maximum at 0.5 to 1 h in all species and declined with half-lives of about 2 h in both rats and monkeys, and of about 4 h in dogs. The ratios of unchanged drug to total radioactivity in the rat and dog plasma were 8 and 43% at 0.5 h after administration, respectively. The radioactivity in the rat tissues was high in the liver, kidney, blood and pancreas after oral administration. Following oral dosage, the urinary excretion of radioactivity was 26-34% of the dose in rats, 45% in dogs and 46% in monkeys in 48 h. The biliary excretion after oral dosage amounted to 66% and 41% in rats and dogs, respectively. Six metabolites were isolated and identified from the urine of rats and dogs. They were derived from one or two of the following pathways: I, hydroxylation of the 2-methyl group of the methylbenzenesulphonamide ring; II, demethylation of the o-methoxy group of the methoxyphenoxy ring; III, hydroxylation at the 4 or 5 position of the methoxyphenoxy ring; IV, oxidative cleavage of the C-N bond yielding o-methoxyphenoxy acetic acid. Moreover, some metabolites were metabolized to glucuronide or sulphate.

Adrenergic alpha-Antagonists↗
PubMed1983

Determination of the alpha, beta-adrenoceptor blocker YM-09538 in urine by gas chromatography with a nitrogen-sensitive detector.

A gas chromatographic method for the quantitative determination of the alpha, beta-adrenoceptor blocker YM-09538 in urine is described. YM-09538 was extracted from alkalinized urine with ethyl acetate and converted to its cyclic methylboronate derivative. Analysis by gas chromatography using a nitrogen-sensitive detector allowed quantitation of the drug over a concentration range of 0.2-5.0 micrograms/ml. Urinary excretion of YM-09538 was determined in humans after oral administration of 50 mg.

Adrenergic alpha-Antagonists↗
PubMed1982

Quantitative determination of the beta-adrenoceptor stimulant formoterol in urine by gas chromatography mass spectrometry.

A method for the quantitative determination of the beta-stimulant formoterol in urine, using a gas chromatograph--mass spectrometer, is described. Formoterol can be analyzed after the addition of a deuterium-labelled internal standard and conversion to a mixed bis-pentafluoropropionyl-methyl derivative for selected ion monitoring. The detection limit was 5 ng/ml. Urinalysis after the oral administration of formoterol fumarate, using a combined enzymic hydrolysis method, revealed that the drug was conjugated with glucuronic acid in rats, dogs and humans.

Adrenergic beta-Agonists↗
PubMed1982

Bioavailability of griseofulvin from tablets in beagle dogs and correlation with dissolution rate and bioavailability in humans.

The bioavailability of four griseofulvin tablets in beagle dogs, including an ultramicrosize tablet used previously in a human bioavailability study, was investigated on the basis of the plasma 6-demethyl-griseofulvin concentration. The relations with the in vivo findings in humans and the in vitro dissolution rates also were examined. Contrary to the lower bioavailability of the ultramicrosize formulation in humans, it provided the best bioavailability in beagles. The microsize griseofulvin formulations showed similar in vivo results to those in humans. Poor correlation of in vivo parameters between humans and beagles was attributed to the discrepancy of the availability of the ultramicrosize formulation between the two species. The dissolution rates determined by the pretreatment method using plastic beads were correlated more with the in vivo findings than those determined by the other methods. Beagles were a useful animal model for bioavailability studies of certain griseofulvin formulations but not ultramicrosize ones.

Animals↗
PubMed1982

Disposition and metabolism of formoterol fumarate, a new bronchodilator, in rats and dogs.

1. The disposition and metabolism of formoterol fumarate, a highly potent beta 2-adrenoceptor stimulant, were studied in rats and dogs. 2. After oral administration of [3H] formoterol fumarate to dogs, unchanged formoterol accounted for greater than 60% of the plasma radioactivity immediately after dosage; greater than 20% was due to the unchanged drug until 12 h after dosage. In contrast, only 1-3% of the radioactivity was present as unchanged drug in rat plasma. After i.v. dosage, unchanged drug was much higher in both species. The elimination half-life of formoterol was 4-6 h in dogs and 1.7 h in rats. 3. In both species, 36-45% of the dose was excreted in urine and 50-56% in faeces in 72 h, irrespective of the administration route. Biliary excretion after oral dosage amounted to 65 and 31% in rats and dogs, respectively. 4. T.l.c. before and after enzymic hydrolysis revealed that the drug was excreted in urine and bile of rats mostly as a conjugate. Dog urine also contained the conjugate but the unchanged drug was much higher than in rats. The conjugated metabolite was purified from rat urine and identified as the 2-O-glucuronide. The glucuronide was the only metabolite detected in the urine and bile of rats and in the urine of dogs.

Administration, Oral↗
PubMed1981

Determination of the alpha,beta-adrenoceptor blocker YM-09538 in plasma by high-performance liquid chromatography with fluorescence detection.

A high-performance liquid chromatographic method for the determination of the alpha,beta-adrenoceptor blocker 5-(1-hydroxy-2-[2-(o-methoxyphenoxy)ethylamino]ethyl]-2-methyl-benzenesulphonamide hydrochloride (YM-09538) in plasma, using 5-di-n-butylaminonaphthalene-1-sulphonyl chloride as a reagent for fluorescence labelling is described. The detection limit is 20 ng/ml, which is sensitive enough to determine YM-09538 plasma levels after the oral administration of effective doses to dogs and human.

Animals↗
PubMed1981

Simultaneous detection of several Fusarium mycotoxins in cereals, grains, and foodstuffs.

A systematic method is described for the simultaneous determination of Fusarium mycotoxins (nivalenol, deoxynivalenol, fusarenon-x, diacetoxyscirpenol, neosolaniol, T-2 toxin, HT-2 toxin, butenolide, moniliformin, and zearalenone) in cereals, grains, and foodstuffs. Mycotoxins were extracted with aqueous methanol and purified by a 2-step chromatographic procedure using Amberlite XAD-4 and Florisil columns. The column eluates were concentrated and spotted on a thin layer chromatographic (TLC) plate which was then developed in CHCL3-methanol (93 + 7) and toluene-acetone-methanol (5 + 3 + 2). Each mycotoxin was quantitated by gas chromatography (GC) and TLC densitometry. The minimum detectable concentrations (microgram/kg) in various test materials were: nivalenol, deoxynivalenol, and fusarenon-x, 2.0; diacetoxyscirpenol, neosolaniol, T-2 toxin, and HT-2 toxin, 80; zearalenone, 10; butenolide, 30; and moniliformin, 50. Recoveries of the mycotoxins added to various cereal samples at 1.0-2.0 microgram/g were greater than 71% and averaged 85%.

Chromatography↗
PubMed1979

Simultaneous determination of griseofulvin and 6-desmethylgriseofulvin in plasma by electron-capture gas chromatography.

Two methods have been developed for the simultaneous determination of griseofulvin and its major metabolite 6-desmethylgriseofulvin in plasma using electron-capture gas chromatography. The first method was based on the quantitative reversion of the 6-desmethyl metabolite to griseofulvin by diazomethane. Plasma extract was chromatographed both before and after treatment with diazomethane, the former being the measure of griseofulvin and the latter representing the sum of the two compounds. In the second method, plasma extract was treated with diazobutane and griseofulvin and the butylated metabolite were separated by gas chromatography. The sensitivity for griseofulvin was 20 ng/ml by both methods and that for the metabolite was 20 ng/ml and 40 ng/ml by the first and the second method, respectively. The concentrations of the metabolite as well as griseofulvin were determined in dog and human plasma after oral administration of griseofulvin.

Animals↗