Organosilicate-polymer drug delivery systems: controlled release and enhanced mechanical properties

Dexamethasone-loaded poly(ethylene-co-vinyl acetate) (EVAc) nanocomposites were fabricated via solution-casting with three different organosilicates for study in a drug delivery system. X-ray diffraction (XRD) showed that all three nanocomposites were in an intercalated morphology. Release studies of dexamethasone into phosphate-buffered saline revealed that the presence of silicates reduced the rate of drug release, and this reduction was a function of volume fraction of silicate in the composite, as well as the aspect ratio of the silicate layers. It was also found that the presence of silicate in a nanocomposite resulted in an increase in the Young's modulus as compared to the pure polymer, and this increase was also a function of the volume fraction of silicate present as well as the aspect ratio of the silicate layers. Silicates are a viable additive to EVAc drug delivery systems, providing controlled release characteristics as well as enhanced mechanical properties in an economically and biologically safe manner. (C) 2003 Elsevier Science B.V. All rights reserved.