Study on the peroral absorption of the endekapeptide cyclosporine A

The beagle dog was found to be a suitable model for pharmacokinetic and bioavailability studies of cyclosporine A (CsA). All pharmacokinetic parameters studied were in the same order of magnitude as those found in man. Three CsA peroral formulations in the form of capsules were compared with a commercially available P.O. solution (to be diluted for administration) and a solution for intravenous administration. Of the three experimental capsule formulations, one based on a microemulsion resulted in an extent of absolute and relative bioavailability not different from that of the available P.O. solution. The advantage, however, is that it is a capsule preparation, ready to swallow, and does not need any manipulation by the patient to dilute the solution. The other two capsule preparations, based on a Gelucire gel with sorption promoters and a microemulsion containing Azone, resulted in a lesser bioavailability than the solution.