REGULATION OF DRUG RELEASE USING HETEROGENEOUS POLYMER MATRIX

Abstract

Poly(N-isopropyl acrylamide)(IPAAm) shows a remarkable change in aqueous swelling with a change in temperature. Random copolymers of IPAAm and butyl methacrylate(BMA), hexylmethacrylate(HMA), or lauryl methacrylate(LMA) were systhesized and indomethacin was loaded into these polymers. Drug release experiment was performed at each temperature. At constant temperature, release pattern was observed as zero order release pattern when temperature was low. This can be explained in terms of permeability increase in polymer matrix and agree with release pattern derived from model. Pulsate release patternrn was found to be regulated by temperature flactuation between 20°C and 30°C due to surface shrinking layer with an increase in temperature. In the case of 20hr for 3°C, release rate remained constant. The results suggested that loaded drug in polymer migrates to the syrface at 30°C even if release was completely stopped.