Solution for inverse problem of medicine's one-dimensional diffusion out of chitosan film

The paper deals with one-dimensional model of medicine's diffusion out from the chitosan film (plaster) in surrounding water. The film's diffusion characteristics are determined using the set of measured average medicine concentrations in the film. The method is based on using of analytical solution of direct diffusion problem. Medicine's behaviour on the boundary of film and water may be described by the conditions of the first or of the third kind. The cases of constant and time-dependent (tending to zero as time increases) diffusion coefficient are discussed. The paper shows that using first-kind boundary conditions with the hypothesis about time-dependent diffusion coefficient leads to the best matching with experimental data.