Using chitosan and xanthan gum mixtures as excipients in controlled release formulations of ambroxol HCl - in vitro drug release and swelling behavior

Directly compressed matrices were produced using a binary mixture of different chitosan (CH) and xanthan gum (XG) ratios. These hydrophilic excipients were used to control the release of ambroxol HCl. CH and XG were investigated at three ratios of 1:1, 1:4 and 4:1. Mucosolvan LA® was used as a commercially available reference product. The optimal CH to XG ratio was 1:1 and the optimal drug to polymer ratio was 1:3. Matrix erosion, hydration and drug release studies were carried out using a dissolution apparatus (basket method). The release mechanism is also discussed