No abstract

The bioavailability of 2 kinds of digoxin tablets (0.25mg) on the Japanese market was compared. Two tablets were given daily in empty stomach to 3 each of healthy men and women. Serum levels of digoxin were measured by radioimmunoassay before and 0.5, 1, 2, 4 and 6 hours after the administration.In vitro tests were performed to determine the weight variation, hardness, content, disintegration time and dissolution time of the tablets. As a result, some differences in the test items were found although they might be caused by additives in the tablets.There was no statistically significant difference in the serum level among the products because of the fact that the difference among the human subjects was larger than that among the products. Therefore, it can be said on the basis of the in vitro and in vivo tests that the two products are interchangeable.But the blood level of digoxin should occasionally be determined in patients under this therapy because of individual difference in bioavilability.

Dissolution profiles of a few sustained release preparations containing $-blockers were examined in media of various pH.Dissolution patterns of carteolol from Mikelan-LA tablets were found to be independent of pH values of media,while those from sustained release products containing pindolol depended on pH values of media.The latters consisted of pH-independent fast dissolving part and pH-dependent sustained release part.There were also difference in dissolution rates among brands.In Blocklin-L capsule,apparent dissolution rates of pindolol at pH 5.0-6.0 exceeded those at the first and second dissolution media of JP XII when UV absorbance was measured.Its dissolution rates measured by HPLC were found to be smaller than those measured by UV absorbance.Some material(s) was likely to be dissolved in dissolution media from capsule ingredients which exhibited UV absorption only at pH 5.0-6.0.