Phases in temporal multiscale evolution of drug release mechanism from IPN-type chitosan based hydrogels

The paper proposes modeling calcein release kinetics (considered hydrophilic drug model) from interpenetrating network matrix of hydrogel type, based on combinations of two polymers, of which the chitosan is common. The release process is analyzed for different increasing time intervals, divided upon release kinetics evolution. For each time interval, a dominant release mechanism was identified and quantitative analysis were performed, probing the existence of four distinct stages during its evolution, each governed by a different kinetic model. An interesting and original aspect, analyzed through a novel approach, is that of drug release at long time scales, often overlooked. It revealed that system behaves as a complex one and its evolution can be described through a nonlinear theoretical model, that offer new insights on its order-disorder evolution.