An Alcohol‐Free SiO 2 Sol‐Gel Matrix Functionalized with Acetic Acid as Drug Reservoir for the Controlled Release of Pentoxifylline

Pentoxifylline (PTX) is a xanthine derivative, with hemorrheologic properties, that has been useful in the treatment of several diseases. However, a conventional route of administration implies high doses, what is unnecessary to the organism, seriously increasing the risk of toxicity because of side effects. Because of the facility to modify their surface, sol‐gel materials have proved to be suitable reservoirs for a variety of molecules for biological applications. In this work we prepared alcohol‐free SiO 2 material by the sol‐gel process using acetic acid as surface modifier and hydrolysis catalyst, the alkoxide/water ratio (Rw) used was 1/16, and tetraethylorthosilicate was used as SiO 2 precursor. Spectroscopic characterization was carried out by means of FTIR‐ATR and UV‐Visible spectroscopies; the results confirmed the presence of the drug and interactions between sol‐gel matrix and PTX. BET specific surface area values of the sol‐gel materials were 365 and 462 m 2 /g for SiO 2 and PTX‐SiO 2 , respectively. Synthesized SiO 2 nanoparticles showed efficient entrapment of PTX since a controlled release of 83% of drug content was reached.