The aim of this study was to prepare organically modified silica xerogels by a two-step acid/base catalyzed sol-gel process that would provide a slow release of an anticancer drug -doxorubicin hydrochloride (DOX). The influence of different amounts of PDMS added on the properties of xerogels intended for the release of the drug and the dissolution of xerogels was investigated. SEM, BET, IR and nitrogen gas adsorption/desorption measurements were performed to characterize the microstructures and chemical properties of xerogels. It is shown that an increase in the proportion of PDMS in the silica network is associated with a decrease in bulk density, specific surface area, total volume of pores and proportion of silanol groups (higher hydrophobicity). These results also revealed the influence of PDMS on the release of doxorubicin hydrochloride and the dissolution behavior of xerogels. An increase in PDMS content results in a decrease in both the rate of drug release and dissolution of xerogels. After the release study, the changes of microstructures and physicochemical properties of these xerogels were also examined.