CONTROLLED-RELEASE OF THEOPHYLLINE MONOHYDRATE FROM AMYLODEXTRIN TABLETS - IN-VITRO OBSERVATIONS

Amylodextrin is a linear dextrin and can be produced by enzymatic hydr olysis of the alpha-1,6 glycosidic bonds of amylopectin. Tablets compa cted from pure amylodextrin showed good binding properties and did not disintegrate in aqueous media. Extended and decreasing drug release r ates were found for tablets of 300 mg with a diameter of 9 mm containi ng 70% amylodextrin and 30% theophylline monohydrate, when compacted a t 5 kN. Almost-constant drug release rates were obtained for these tab lets when compacted at 10 or 15 kN. Nearly constant drug release rates were also shown for amylodextrin tablets with a drug load up to 75% c ompacted at 10 kN. Both release rate and release profile could be adju sted by selecting tablet thickness and incorporation of either lactose as a highly soluble excipient or talc as a hydrophobic excipient.