Mechanistic modeling of drug release from chitosan coated tablets

A mechanistic model for drug release from tablets coated with chitosan was derived, assuming that: (1) core tablets are spherical and the drug dissolution is diffusion dependent. (2) In order for the drug release to occur, dissolution medium penetrates through the coated film and leaches out the drug through the film and the lag-time, t(lag) is set for these processes. (3) The coated film itself dissolves and becomes thinner with time. (4) After the film has completely dissipated and the undissolved core tablet becomes naked, drug release proceeds just as the spherical core tablet. Drug release rate was given as a differential equation. Model adaptation was carried out to the release data of propranolol hydrochloride tablets coated with chitosan and kept in different storage conditions. The goodness-of-fit of our model was better than any other conventional equations tested and estimated model parameters were informative.