Influence of the inorganic matrix nature on the sustained release of naproxen

Naproxen, a non-steroidal anti-inflammatory drug, has been immobilised in different inorganic matrices, namely Mg, Al layered double hydroxide (LDH), MCM-41 mesoporous silica and mesoporous alumina. The synthesised systems were characterised using several physicochemical techniques and their delivery rates tested through in vitro experiments. It was found that the amounts of drugs incorporated in the mesoporous matrices are quite similar, ranging between ca. 15 and 20% in wt, mainly depending on their pore size, while the LDH can host up to ca. 41% wt. In all cases the release rate of naproxen for the mesoporous systems is lower than that detected measured for the LDH system and all of them can be well fitted to the Fick’s law.