In vitro release dynamics of insulin from a loaded hydrophilic polymeric network.

A hydrophilic semi-interpenetrating polymer network of polyvinyl alcohol (PVA), poly(ethylene glycol) (PEG) and crosslinked polyacrylamide (PAM) chains has been synthesized and its potential for controlled release of macromolecular drugs has been assessed by taking insulin as a representative drug. The semi-IPN was characterized by IR studies and network parameters such as the average molecular weight between crosslinks (Mc), crosslink density (q), and number of elastically effective chains (Ve) were evaluated. The effect of chemical architecture of the IPN was investigated on the percent loading of insulin and its subsequent release from the loaded device. Other parameters such as the thickness of the gel, molecular weight of PEG and pH and temperature of the release medium were also studied for their possible impact on the release of insulin. The whole release data was analyzed by Ficks power law and the influence of various factors on the plausible mechanism of insulin release was investigated.