PREPARATION, CHARACTERIZATION, AND PHARMACEUTICAL APPLICATION OF LINEAR DEXTRINS .2. COMPLEXATION AND DISPERSION OF DRUGS WITH AMYLODEXTRINBY FREEZE-DRYING AND KNEADING

The ability of amylodextrin (a linear dextrin) to act as a complexing agent or as a carrier for solid dispersion was evaluated. Blends of am ylodextrin with diazepam or prednisolone were freeze-dried and kneaded at elevated temperatures, respectively. The products were analyzed by DSC, X-ray diffractometry, and FTIR spectroscopy. Complex formation w ith amylodextrin by freeze-drying was found not to occur for diazepam but for prednisolone at a molar ratio of 1 to 1. The freeze-dried prod uct of diazepam with amylodextrin proved to be a solid dispersion. Sol id dispersions were formed by both wet (with ethanol) and dry kneading at elevated temperatures of low-melting drugs such as lidocain, diaze pam, and methyl-PABA with amylodextrin. No solid dispersions were obta ined for high-melting drugs such as prednisolone and salicylic acid. T he results point to the formation of solid dispersions by a melting me chanism during the process of kneading at elevated temperatures of low -melting drugs with amylodextrin.