Enhancement of dissolution rates of several drugs by low-molecular chitosan and alginate.

Abstract

The dissolution behaviors of acidic, basic and neutral drugs from kneaded mixtures with low-molecular chitosan or alginate (LM chitosan or LM alginate) have been studied in comparison with that of the drug alone. The results revealed a significant increase of dissolution rate of drugs from kneaded mixtures. Although essentially no interaction of any drug with LM chitosan or LM alginate was observed in an aqueous solution, changes of drug crystals in the kneaded mixtures were apparent. In addition, the contact angle of kneaded mixtures was obviously reduced in comparison with that of the corresponding drug powder and physical mixture.Thus, the enhanced dissolution rate of kneaded mixtures may be due to improvement of wettability and to changes of the crystallinity, microcrystal size and shape.