Study on the "in vitro" controlled release of active substances from transdermal therapeutical systems

The paper presents the achievement and characterization of some new transdermal therapeutical systems based on polymeric matrix, with a controlled release of active substance. For investigations, there were used polymeric matrices based on polyvinylic alcohol, and as an active substance was used the salicylic acid The experimental basis of this paper consists in achieving the kinetic profiles for the active substance release from the polymeric system, using the experimental determinations and the concentration gradients calculus of the active substance, as well as the mass transfer coefficients. Based on the kinetic evaluation of the diffusion process of the active substance from the polymeric matrix, the study of the in vitro release allows the optimisation of the system concerning the quality of the experimental model, for the orientation of in vivo experiments.