DRUG LIBERATION FROM POLYMER-HYDROGELS .1. KINETICS OF THE PROCESS

The drug liberation of dissolved and suspended pharmacons was studied from hydrogels, which contained gel-forming polymers. The process of l iberation was studied on a flow-through membrane diffusion model. The quantities of the liberated drugs were measured as a function of the f low-through time and the cumulative curves were drawn. It was found th at the relation between the quantity of the liberated pharmacon and th e diffusion time could be described with a power function the exponent of which was 0.5. The validity of the relation did not depend on the type of the polymer, on the gel-forming concentration or on the type o f pharmacon dispersion.