The megaloporous system: A novel principle for zero-order drug delivery. II. A model for the mechanism of drug delivery

The megaloporous system is composed of two phases with different liquid-penetration properties (the housing matrix phase and the restraining matrix phase) and delivers most of its drug content at a zero-order rate. The mechanism of drug release from the system is based on the concept of a decrease in the rate of surface area exposure in time of the restraining matrix phase (containing the drug) to the penetration liquid with simultaneously an increase in time of the total restraining matrix phase surface area, contributing to the delivery process. This model is mathematically represented by a convolution integral. It provides an explanation for the substantially constant release characteristics of drug from the megaloporous system. By using empirical equations in the convolution integral for the rate of restraining phase unit supply to the extraction liquids and for the drug release function of one restraining phase unit, it can be concluded that the model adequately describes the release principle of the megaloporous system