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Biomedical subjects

N Aoyagi

Publications and source records attributed to N Aoyagi.

At least 91 records · Page 5Linked to original sources
PubMed1984

Bioavailability of nalidixic acid from uncoated tablets in humans--Part I: Correlation with the dissolution rates of the tablets.

Bioavailabilities of three commercially available tablets and two trial tablets of nalidixic acid were determined. The correlation between in vivo bioavailability parameters and in vitro dissolution rates derived by eight methods (oscillating basket I and II, beaker I, II, and III, rotating basket, paddle and rotating flask) is discussed. Nalidixic acid and its metabolite, 7-hydroxynalidixic acid, were determined in serum by HPLC with a strong anion-exchange resin column. All parameters for nalidixic acid bioavailability showed significant differences among the tablets tested. The relationship between Cmax and AUC was not linear but concave. However, Cmax decreased linearly in proportion to the delay of Tmax. The rank order of tablets according to bioavailabilities was just the same as the rank order obtained when comparing dissolution rates determined by any of the above methods, with the exception of one tablet which had a poor disintegrating ability. The parameters for the rate of bioavailability (Cmax and Tmax) showed good linearity with 1/T50 determined by all of the methods. However, AUC showed significant correlation with neither T50 nor 1/T50.

Adult↗
PubMed1984

Bioavailability of Nalidixic acid from uncoated tablets in humans--Part II: Bioavailability in beagles and its correlation with bioavailability in humans and in vitro dissolution rates.

The bioavailability of nalidixic acid in beagles was determined using the same tablet formulations previously tested on humans and was compared with bioavailability in humans and with in vitro dissolution rates. The beagle bioavailability test provided lower power in all of the bioavailability parameters than did the human test. Tmax of the tablets did not greatly differ in beagles, although in humans a wide variation of Tmax was seen. A linearity between Cmax and AUC0-infinity was observed in beagles, but Tmax did not show a linearity with Cmax or AUC in dogs, which is quite different from the relations observed in humans. The rank order of tablets according to Cmax was exactly the same between humans and beagles. AUC also showed the same rank order between humans and beagles except for on tablet with a poor disintegrating ability. A significant correlation between human and beagle Cmax values was obtained (r = 0.8952; p less than 0.05), but not between human and beagle AUC and Tmax values.

Animals↗
PubMed1983

Acute myelomonocytic leukemia following remission of sarcoidosis.

A 55-year-old woman was described who developed an acute myelomonocytic leukemia 4 years after remission of sarcoidosis. This association is of particular interest since pronounced T cell dysfunction appears in sarcoidosis. We traced serum angiotensin-converting enzyme and serum or urinary lysozyme levels of this patient.

Clinical Enzyme Tests↗
PubMed1983

[Analysis of 223 cases of intracranial aneurysms--with special reference to re-rupture of the intracranial aneurysms].

Reviewing 223 cases of intracranial ruptured aneurysms including 46 cases of re-ruptured aneurysms, the following results were obtained. 1) The outcome of the re-rupture aneurysms was more miserable than that of the first rupture. Even low grade cases (Hunt and Hess 0-II) of re-rupture showed no better outcome than high grade cases (Hunt and Hess IV) of first rupture. 2) Re-rupture most often occurred on the 12th (11.6 +/- 6.7) day after the first attack of the subarachnoid hemorrhage. Re-rupture more often occurred in the vertebrobasilar system. In the internal carotid artery and its branches, aneurysms with daughter or bleb tended to rupture again. Aneurysms with daughter, regardless of these location, showed greater incidence of re-rupture than those without daughter. Also rupture often occurred in the cases of lower grade with less vasospasm and with the acute hydrocephalus. 3) It was suggested that the sequential changes of some factors of both the coagulating system and fibrinolytic system might forecast the vasospasm, infarction, re-rupture and prognosis of the patient of intracranial ruptured aneurysms. And therefore, in the cases in which re-rupture is likely, operation should be performed as early as possible, except in those showing diffuse vasospasm or clinical down hill course or in grade V.

Adult↗
PubMed1983

The bioavailability of flufenamic acid and its dissolution rate from capsules.

The bioavailabilities of five commercially available flufenamic acid (FA) capsules were studied in humans and beagle dogs. The dissolution rates of these capsules were determined by several methods. Experiments on in vitro/in vivo and humans/dogs correlations were performed to evaluate the dissolution test methods and the values of beagle dogs as models for predicting bioavailability of weak acid drugs in humans. Significant differences in the rates and extents of bioavailability of the different capsules were observed both in humans and dogs, but results in humans differed from those in dogs. The dissolution rates, determined by dissolution methods involving pretreatment with acidic solutions, correlated significantly with bioavailabilities in humans and dogs; however, those obtained by the rotating basket and paddle methods without any surface active agents did not correlate with in vivo data.

Adult↗
PubMed1982

Bioavailability of griseofulvin from tablets in humans and the correlation with its dissolution rate.

Dissolution rates of 10 commercial microsize griseofulvin tablets and one ultramicrosize griseofulvin tablet were preliminarily determined in 18 liters of pH 7.2 phosphate buffer and in 900 ml of 40% dimethylformamide as test media. Addition of dimethylformamide affected the dissolution behavior of the formulations. The products, three microsize and one ultramicrosize, were selected for further studies on the bioavailability in humans and dissolution. Significant differences among the formulations were found in serum levels Cmax, and AUC47.5 hr, but not in AUC infinity and tmax. The maximum difference of Cmax was approximately 40%. The ultramicrosize product showed lower Cmax and serum levels at earlier sampling times than two microsize products. The dissolution rates determined under sink and nonsink conditions without pretreatment significantly correlated with the serum level at 1 hr but not with the other in vivo parameters. Only the dissolution rate determined by the sink method with pretreatment with a small quantity of water (1.0 ml) and plastic beads significantly correlated with serum levels at 3 and 5 hr, Cmax, and AUC 47.5 hr.

Biological Availability↗
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

Effect of food on the bioavailability of griseofulvin from microsize and PEG ultramicrosize (GRIS-PEG) plain tablets.

Effect of food on the bioavailability of griseofulvin from its two plain tablets, a commercial microsize product and a PEG ultramicrosize (GRIS-PEGR) one, was investigated. The drug was dissolved at a slower rate from ultramicrosize formulation than from microsize one in 18 1 of pH 7.2 buffer but at a little faster rate in 40% dimethylformamide. When administered to fasting subjects, the microsize product showed higher serum levels and peak serum level than ultramicrosize one but the extent of the bioavailability was nearly the same. A standard breakfast enhanced the rate of absorption of the drug from both the products, especially from ultramicrosize one, and those products were equivalent in the rate and extent of bioavailability after food ingestion. The peak serum level of ultramicrosize product in nonfasting was about twice higher than that in fasting subjects. The different intensities of food effect on the bioavailabilities from two dosage forms suggest that formulation factors should be considered for the evaluation of food effect.

Adult↗
PubMed1982

The bioavailability of flufenamic acid from aluminum flufenamate tablet and flufenamic acid capsule, and the influence of food and aluminum hydroxide gel.

The bioavailabilities of flufenamic acid (I) from a commercial aluminum flufenamate (II) tablet and I capsule were estimated by measuring urinary excretion of I and its metabolites fluorometrically. The dissolution rates of I from both dosage forms were also determined. The effects of concomitant intake of food or antacid on the bioavailabilities from the II tablet and the I capsule were investigated. The extent on I bioavailability from the II tablet was less than 30% of that from the I capsule. Dissolution tests suggested that the low bioavailability of I from II tablet resulted from the extremely slow release of I from the II complex. Intake of a standard meal retarded I absorption from I capsule, but did not affect that from the II tablet. Ingestion of dried aluminum hydroxide gel granules had little effect on I bioavailability from the I capsule.

Adult↗