Carboxylic acid decorated silica aerogel nanostructure as drug delivery carrier

Surface functionalization of silica aerogel could pioneer great utilities, including the modified release of loaded drugs through the specific interaction that emerged. In this work, the effect of carboxylic modification of silica aerogel on drug loading capacity and drug dissolution rate was studied to evaluate as celecoxib (CCB) delivery carrier. The modification was successfully carried out on calcined ambient pressure dried silica aerogel (SA-OH) through two-step treating with N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTES) and then succinic anhydride. The characterization methods of FT-IR, FE-SEM, nitrogen adsorption-desorption analysis, TGA, DSC, XRD, zeta-potential measurements, and UV-spectrophotometry were used to study the surface modification and drug loading process systematically. The results have shown that the modification to grafting the terminal –COOH groups on the SA-OH were successfully carried out. The modified aerogels have a similar mesoporous structure to the original ones with a smaller mean pore size. After CCB loading on the carriers, its crystallinity state converts to the non-crystalline and amorphous in the SA-OH and SA-COOH carriers, respectively. Besides, loading on SA-COOH benefits the COO− - NH3+ bonding between carrier and drug functional groups. Drug release results displayed a faster drug dissolution from both carriers than the pure drug, and the controlled release rate was observed from SA-COOH/CCB compared with the SA-OH/CCB due to the existence of stronger bonding and smaller pore size. It was found that SA-COOH has good potential, considering the ability to adjust drug dissolution and exhibiting good biocompatibility on exposure to model cell line.