Dense silica material offers a crucial niche in the adaptable drug release domain due to its relatively straightforward synthesis and favorable internal structure for encapsulating drug substances. To support the development of silica-based drug delivery systems with optimized drug release kinetics, it is important to understand the structure-function relationship that drives silica matrix dissolution. This study provides a concise physical characterization of dense, non-mesoporous silica microparticles and examines how surface area and pore volume modulate dissolution behavior in a matrix-erosion-driven drug release system. Surface area and total pore volume were found to influence silica dissolution, with higher surface areas leading to faster silica matrix degradation. Gas adsorption analysis demonstrated that the microparticles exhibit either Type I or Type II isotherms, indicating microporous or non-porous structures. A homogeneous drug distribution in the silica microparticles was demonstrated by broad ion beam - scanning electron microscopy and energy dispersive X-ray analysis, and was supported by in vitro dissolution studies. This study has shown that gas adsorption-desorption measurements are a useful tool for determining surface properties and related pore sizes in these silica materials. The surface area was observed to be a contributing factor to the rate of dissolution of silica microparticles. Furthermore, the drug release was demonstrated to be mainly controlled by silica dissolution for a non-porous type of silica microparticles.
J.Kadiri et al. (Thu,) studied this question.