Controlled release silica sol-gels are room temperature processed, porous, resorbable, and
biocompatible materials. Many molecules including drugs, proteins, and growth factors can be
released from sol-gels, and the quantity and duration of the release can vary widely. Processing
parameters render these release properties exquisitely versatile [1]. The synthesis of controlled
release sol-gels involves several steps: an acid-catalyzed hydrolysis to form a sol with the molecules
included, followed by casting, aging, and drying. Additional steps such as grinding and sieving are
required to produce sol-gel granules of a desirable size. In this study, we focus on the synthesis of
controlled release sol-gel microspheres by using a novel process, which involves only two steps:sol
formation followed by emulsification. Sol-gel microspheres containing either vancomycin
(antibiotic) or bupivacaine (analgesic) were successfully synthesized via this synthesis route. Both
drugs showed controlled, load-dependent and time-dependent release from the microspheres. The in
vitro release properties of sol-gel microspheres were different from those of sol-gel granules
produced by grinding and sieving. In comparison to a fast, short-term release from the granules, the
release from the microspheres was slower and of longer duration. In addition, the degradation rate of
microspheres was significantly slower than that of the granules. These data enable the use of sol-gel
powders for controlled long-term release.
In Vitro Release of Cisplatin from Sol-Gel Processed Porous Silica Xerogels
