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Biomedical subjects

A Ejima

Publications and source records attributed to A Ejima.

At least 55 records · Page 3Linked to original sources
PubMed1985

Bioavailability of indomethacin capsules in humans (III): Correlation with bioavailability in beagle dogs.

The bioavailabilities of five indomethacin capsules were studied in ten beagle dogs and correlations with the in vivo results in humans and dissolution rates were investigated. The difference in bioavailability between two commercial products was smaller in dogs than in humans, which seemed to be due to strong disintegration forces in dogs. The difference in the dissolution rate among the products was reflected less in the Tmax in dogs than in humans, and the Tmax was shorter in dogs which seems to be due to faster gastric emptying and passage of the drug through the absorption site in dogs. Gastric acidity effects on the indomethacin availability found in humans were not observed in dogs. The Cmax and Tmax correlated well with the in vitro dissolution rates, but AUC24 did not. The Cmax and Tmax in dogs also correlated with the corresponding parameters in humans, especially those in high gastric acidity humans, but AUC24 did not.

Animals↗
PubMed1984

Bioavailability of griseofulvin plain tablets in stomach-emptying controlled rabbits and the correlation with bioavailability in humans.

Bioavailability after giving oral doses of 62.5 mg griseofulvin tablets having different dissolution rates to stomach-emptying controlled rabbits, was estimated and compared with that in humans receiving 125 mg dose of the same griseofulvin preparations. The relative differences in Cmax and AUC infinity between the product with the highest availability and others tended to be greater in rabbits than in humans. The in vivo parameters correlated well between the two species. However, power analysis indicated a larger variability of Cmax in rabbits than in other species (dogs, minipigs and humans). Water volume (5 and 50 ml) coadministered with the drug did not significantly influence the bioavailability. The rabbits which were not given food after oral dosing with griseofulvin exhibited a lower Cmax than those which were fed immediately after dosing. The bioavailability of an ultramicronized formulation in rabbits was higher after the postprandial dose than after the preprandial dose. Food intake just after the drug administration seems to be an important factor for controlling the passage rate of the drug through the gastrointestinal tract in stomach-emptying controlled rabbits.

Animals↗
PubMed1984

Development and evaluation of a new peroral test agent GA-test for assessment of gastric acidity.

A new peroral test capsule, GA-Test, containing riboflavin (5 mg) granules coated with polyvinylacetal diethylaminoacetate (AEA) for assessing gastric acidity without intubation was developed and evaluated for usefulness. GA-Test is based on the tracing in the urine of riboflavin, which is released in the stomach only in the presence of acidic fluid and is absorbed. Due to the film coating, riboflavin released very quickly at a pH of less than 5, and not at all at a pH of greater than 6. GA-Test gave a significant correlation, quantitatively, with peroral Gastrotest in assessing acidity, a non-intubation method which had been marketed in Japan prior to 1980. GA-Test results allowed division of the subjects into two groups i.e., subjects having low (hypo- or anacidity) gastric acidity and those having high (normal or hyperacidity) gastric acidity, GA-Test results agreed well with results of intubation (around 91.4%; 32 out of 35 cases) and were easily reproduced during the evaluation.

Adult↗
PubMed1984

Bioavailability of griseofulvin from plain tablets in Göttingen minipigs and the correlation with bioavailability in humans.

Intravenous administration of 125 mg of griseofulvin to G ottingen minipigs showed biexponential elimination of the drug from plasma, in which the half lives of the initial and terminal phases were 0.2-0.6 h and 4.3-6.6 h, respectively. The bioavailability of four griseofulvin tablets used in a human bioavailability study was investigated in the pigs and compared with the human results. The differences of Cmax and AUC between the standard product and the others were smaller in the pig than in humans, however, the correlations of Cmax and AUC between humans and minipigs were high for the four products. The differences of Tmax among the products were small, and the Tmax of the standard product was large in the pigs compared with that in humans. In addition, delayed onset of drug absorption was observed in some of the pigs. The findings suggest slow gastric emptying of the drug in the pigs. The statistically small powers for the in vivo parameters observed in the pig, seem to indicate variable absorption of the drug in the animal.

Administration, Oral↗
PubMed1984

Effect of food on bioavailability of nalidixic acid from uncoated tablets having different dissolution rates.

The effect of food on the bioavailability of two single lots of commercial tablets and one trial tablet of nalidixic acid, varying widely in drug dissolution characteristics, was determined in healthy male subjects after oral administration. Four subjects received, in a crossover fashion, a single 250 mg dose in an uncoated tablet during periods of fasting and non-fasting. Significant differences in Cmax, Tmax and AUC0-8 were observed between the tablet having the fastest dissolution rate and the other tablets tested, when administered postprandially. Both Cmax and AUC0-8 were significantly increased after administration of the two tablets exhibiting the poorer dissolution characteristics to the non-fasting subjects. However, food was not observed to affect any of the bioavailability parameters after postprandial administration of the tablet exhibiting the fastest dissolution rate. The improvement of bioavailability of the two tablets exhibiting the poorer dissolution by food intake was ascribable to enhanced dissolution of nalidixic acid resulting from vigorous mixing and agitation in the digestive tract. It was concluded that the effect of food on the bioavailability of nalidixic acid from uncoated tablets varies with formulation factors, especially with dissolution characteristics.

Adult↗
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

Bioavailability of two preparations of furosemide and their pharmacological activity in normal volunteers.

The relative bioavailability and diuretic effect of 2 commercially available tablet preparations of furosemide 40 mg was examined in 10 healthy male volunteers. A close linear relationship between the urinary excretion rate of furosemide and the rate of sodium ion excretion in urine and/or flow rate of urine was demonstrated. There were no significant differences in the urinary excretion of furosemide, sodium and potassium ions or urinary volume following the oral doses. The difference in drug content affected the urinary recovery of furosemide over 24 h but had no effect on the pharmacological response. The analytical power of ANOVA using the various parameters of the responses to furosemide was no lower than when the parameters of urinary excretion of furosemide were used.

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↗