Comparative analysis and properties evaluation of gelatin microspheres crosslinked with glutaraldehyde and 3-glycidoxypropyltrimethoxysilane as drug delivery systems for the antibiotic vancomycin

In the present comparative study, gelatin microspheres (GMs) were prepared by emulsification-solvent-extraction method using well-known crosslinker: glutaraldehyde (GA) and biocompatible silane-coupling agent glycidoxypropyltrimethoxysilane (GPTMS). Crosslinking with GA was done by a definite and common procedure, while GPTMS crosslinking potency was investigated after 5, 10, 24, and 48 h synthesis periods and the fabrication method was adjusted in order for preparation of GMs with optimized morphological and compositional characteristics. The prepared GMs were then evaluated and compared as drug delivery systems for the antibiotic vancomycin (Vm). Morphological observations, FTIR, ninhydrin assay, swelling behavior evaluation and Hydrolytic degradation analysis proved successful modification of GMs and revealed that increasing synthesis time from 5 h to 24 h and 48 h, when using GPTMS as crosslinker, led to formation of morphologically-optimized GMs with highest crosslinking degree ( similar to 50%) and the slowest hydrolytic degradation rate. Such GMs also exhibited most sustained release period of Vm. The antibacterial test results against gram-positive bacterium Staphylococcus aureus, were in accordance with the release profiles of Vm, as well. Together, GPTMS-crosslinked GMs with their preferable characteristics and known as biocompatible gelatin-siloxane hybrids, could act as proper drug delivery systems for the sustained release of the antibiotic vancomycin.