Dissolution characteristics of interactive powder mixtures. 4. Effects of additives on the dissolution of griseofulvin from Emcompress carrier

Abstract

Excipient particles having highly indented surfaces such as Emcompress powder, entrapped drug particles and/or agglomerates, thus hindering their dispersion into the powder mixture and reduced the surface area available for dissolution. The result was a reduction in the dissolution of griseofulvin from such interactive powder systems relative to those excipients which have smooth paniculate surfaces. At pH 1.0 the dissolution efficiency of the drug showed a maximum value since effects arising from indentations were insignificant. On the other hand, at pH 7.0 Emcompress powder was insoluble and hence, indentations, with the drug particles and/or agglomerates entrapped therein, impaired the dissolution process. Filling entrapment sites with additives, e.g. calcium hydrogen phosphate dihydrate, lactose, sucrose and maize starch improved dissolution. Different mechanisms are discussed to explain the role of each filling agent in improving dissolution from the griseofulvin-Emcompress interactive mixtures.