Improving the oral bioavailability of sulpiride by a gastric-retained form in rabbits.

To improve the limited oral bioavailability of sulpiride, a gastric-retained form was developed and evaluated using gastric-emptying-controlled rabbits. The AUC value after oral administration of sulpiride as an aqueous solution was less than that after oral administration of sulpiride original powder. The dissolution was not important as a rate limiting factor for sulpiride oral absorption. Sulpiride was absorbed predominantly from the upper part of the small intestine of the rabbit. A gastric-retained tablet prepared from Carbopol 934P, with sustained-release characteristics, was found to be suitable for improving and extending the oral bioavailability of sulpiride.