Release kinetics of 5-aminosalicylic acid from halloysite

This paper investigates desorption of 5-aminosalicilyc acid (5-ASA) adsorbed onto halloysite (HL). Desorption isotherms were fitted according to kinetic laws obtained considering release of 5-ASA from HL as the phase of desorption of the previously adsorbed drug molecules both inside the nanotubes of HL as onto the surface of clay particles and/or in the inter-particle spaces of their aggregates [28]. Desorption isotherms has been also fitted with other equations frequently used in drug release kinetics studies. The best fitting corresponded to the kinetic model proposed; in agreement with the results of adsorption [28].

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► A novel mechanistic model for in vitro dissolution drug release is proposed.
► The proposed model adequately fits data of drug release from solid inorganic adsorbates.
► The postulated model arises from kinetic laws associated with physical–chemical processes in the solid–liquid interface.
► The proposed model provides real hypotheses about mechanisms implicated in drug release.