Swelling kinetics and release studies of theophylline and aminophylline from acrylic acid-alkyl methacrylate hydrogels

摘要

Swelling kinetics and drug release (theophlline and aminophylline) from acrylic acid-alkyl methacrylate hydrogels are presented. Swelling rate of xerogels decreases as the alkyl chain lengthinthe hydrogels increases because of the increasing hydrophobicity; however, the equilibrium swelling increases with increasing chain length. Drug release from swollen hydrogels is Fickian. Theophylline release is fairly independent of alkyl chain length weheras aminophylline release is highly dependent of alkyl chain length which suggest steric effects and stronger affinity of the latter with the hydrogels. Drug release from xerogels is also different for theorphylline and aminophylline. The release of theophylline from xerogels is diffusion controlled and so, it has only a small dependence on the viscoelastic relaxation of the polymeric matrix. By contrast, release of aminophylline fromxerogels is non-Fickian.