Evaluation of Indomethacin Sustained-Release Suppositories Using a Hydroxypropylmethylcellulose Acetate Succinate-Polyethylene Glycol 2000 Solid Matrix

Abstract

Indomethacin (IM) sustained-release suppositories were prepared by using a solid matrix of cellulose acetate phthalate (CAP) or hydroxypropylmethylcellulose acetate succinate (AS·MF) as a poorly soluble carrier and polyethylene glycol 2000 (PEG 2000) as a soluble carrier, and the utility of AS·MF as a poorly soluble carrier was compared with that of CAP. The release rate of IM from the AS·MF matrix suppositories, as well as that from the CAP matrix suppositories, decreased with increase of the content of AS·MF. The sustained release of IM from the AS·MF matrix suppositories was attributed to the formation of a network structure of AS·MF. Rectal administrations of the CAP or AS·MF matrix suppositories in rabbits resulted in good sustained-release characteristics. The bioavailability of the AS·MF matrix suppositories was higher than that of the CAP matrix suppositories.