Controlled release of small molecules from silica xerogel with limited nanoporosity.
Conventional sol-gel processing requires several distinct steps involving hydrolysis, condensation and drying to obtain a highly porous, glassy solid material. With the goal of achieving controlled release of small molecules, herein we focus on the acceleration of the condensation and drying steps by casting the hydrolyzed sol on a large open surface to achieve a denser 100 % silica xerogel structure. Thus, cast xerogel with a more limited porosity was prepared. The effect of synthesis parameters during sol-gel synthesis on the release kinetics of bupivacaine, vancomycin and cephalexin was investigated. The release kinetics fitted well with the Higuchi model, suggesting a diffusional release mechanism. Combining the release and nanostructure data, the formation mechanism of cast xerogel is described. Without introducing additional precursors or additives into sol-gel systems, sol-gel casting is an easy technique that further expands the applicability of sol-gel materials as excellent carriers for the controlled release of a variety of drugs.
Department of Bioengineering, Center for Bioactive Materials and Tissue Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
Rong
R
Chen
Haibo
H
Qu
Ashwin
A
Agrawal
Shaoyun
S
Guo
Paul
P
Ducheyne
D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics; D002045:Bupivacaine / Q000493:pharmacokinetics; D002506:Cephalexin / Q000493:pharmacokinetics; D005782:Gels; D006868:Hydrolysis; D036103:Nanotechnology; D012822:Silicon Dioxide / Q000737:chemistry*; D014640:Vancomycin / Q000493:pharmacokinetics
D000900:Anti-Bacterial Agents; D005782:Gels; D014640:Vancomycin; D012822:Silicon Dioxide; D002506:Cephalexin; D002045:Bupivacaine