The aim of this work was to study the adsorption/desorption processes of two corticosteroids (6-methylprednisolone and sodium hemisuccinate of 6-methylprednisolone) on a cellulosic polymer of ethylcellulose, the commercial latex, Aquacoat(R). We measured the time, pH and concentration of the drug necessary to produce the best adsorption and its subsequent release. The data were obtained with spectrophotometry and differential scanning calorimetry. Several overlapping mechanism appeared be involved in the adsorption of the drugs. Identification of these mechanisms helped to determine the best conditions for adsorption, and to predict degradation of the drugs.