## Abstract Silica xerogels doped with diclofenac diethylamine were prepared by the solโgel method from a hydrolysed tetraethoxysilane (TEOS) solution containing diclofenac diethylamine. Two different catalysts, drying conditions and levels of water content were used to alter the microstructure of
The controlled release of drugs from emulsified, sol gel processed silica microspheres
โ Scribed by Shula Radin; Tiffany Chen; Paul Ducheyne
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 427 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0142-9612
No coin nor oath required. For personal study only.
โฆ Synopsis
Controlled release silica sol gels are room temperature processed, porous, resorbable materials with generally good compatibility. 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. The synthesis of controlled release sol gels typically includes acid catalyzed hydrolysis to form a sol with the molecules included. This is then 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 sol gel microspheres by using a novel process with only two steps. The novelty is related to acid-base catalysis of the sol prior to emulsification. Sol gel microspheres containing either vancomycin (antibiotic) or bupivacaine (analgesic) were successfully synthesized using this method. Both drugs showed controlled, load dependent and time dependent release from the microspheres. The in vitro release properties of sol gel microspheres were remarkably different from those of sol gel granules produced by grinding and sieving. In contrast to a fast, short-term release from granules, the release from microspheres was slower and of longer duration. In addition, the degradation rate of microspheres was significantly slower than that of the granules. Using various mathematical models, the data reveal that the release from sol gel powder is governed by two distinct phases of release. In addition, the release from emulsified microspheres is delayed, a finding that can be attributed to differences in surface properties of the particles produced by emulsification and those produced by casting and grinding. The presented results represent an excellent data set for designing and implementing preclinical studies.
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## Abstract A single step solโgel process was used to precipitate silica microspheres containing ibuprofen or naproxen for controlled drug delivery applications. The drug release behavior from these systems was analyzed __in vitro__. Pure ibuprofen and naproxen exhibited linear release with time, w
Silica gels that controlled the pore size were prepared by calcination of silica/organic polymer (50/50 wt %) composites prepared by the sol-gel process. Poly-(ethylene oxide) (PEO) -poly(propyrene oxide) (PPO) -PEO triblock copolymers, which are called poloxamers, were used as an organic polymer. T