Abstract

A NEW MATHEMATIC METHOD FOR CALCULATION OF PEPPASSAHLIN MODEL CONSTANTS AND INTERPRET THE RESULTS IN RELATION TO ZERO ORDER, HIGUCHI, KROSMEYER-PEPPAS MODELS AND MICROCAPSULE STRUCTURE IMAGE.

Dr. Omar Y. Mady* and Donia A.

Abstract

It was tried to calculate the constants values of Peppes-Sahlin model (k1&k2) using software packet and a mathematic matrix method for aspirin release data from Eudragit RS100 microcapsules. Then discuss the values of the constants as tool for the drug release mechanisms determination in relation to the physico-chemical microcapsule structure suggested by the author. In addition, applying the new mathematic method suggested by the author as a trial to have an image about the drug release mechanism(s) and the violet of each at every unit time from the microcapsules. The calculation of the Peppes-Sahlin constants (k1&k2) were done at fixed m value for Fickian drug diffusion from the spheres, at m value determined by the software packet and at m value equal to the exponent n value of Krosmeyer- Peppas model. The results showed the inability of using both fixed (m) value for Fickian diffusion from spheres and that calculated by software packet. The using of (m) value equal to (n) value showed the contribution of Fickian diffusion and polymer chain relaxation on the drug release process which is in agreement with the microcapsule structure but sometimes did not in agreement with the overall drug release mechanism. In addition the results cannot used for calculation the percent of drug released by each mechanism at each unite time of the drug release. The application of a new mathematic method using m value equal to n value led to calculate the percent of drug released by each mechanism at each unite time. Also showed the overlap, alternate, predominate and combination of drug release mechanisms at each unite time.

Keywords: New mathematic method, Krosmeyer-Peppas model, Peppas-Sahlin model, Zero order kinetic, Higuchi model.