[Variance of bioavailability of pharmaceutical preparations and analysis of factors affecting it].

Phenytoin (pulverized powder), mefenamic acid (capsule), and sulpiride (film-coated tablet) are currently available on the Japanese market. For absorption of these drugs from their pharmaceutical preparations, they must disintegrate and dissolve during passage through the gastrointestinal tract. The bioavailability of these drugs differ among different pharmaceutical preparations and even for the same preparation. This led to a review of the influence of the features of pharmaceutical preparations and the physicochemical properties of film coating materials as well as the physiologic factors affecting drug bioavailability. The influence of coadministered drugs and concomitant intake of beverages and food on the bioavailability of drugs from pharmaceutical preparations is also described.