Development of thermoresponsive poloxamer in situ gel loaded with gentamicin sulfate for cavity wounds

Abstract

Poloxamer hydrogels are thermoresponsive hydrogels that become fluid when cooled and gel-like when heated. Adding poloxamer 188 to a poloxamer 407 solution increases the overall gelation temperature, thereby allowing adjustments to the window of operating temperatures. The rheological properties of the poloxamer hydrogel, including gelation temperature and gelation time, were investigated, and the biocompatibility, drug release, and antibacterial properties of a gentamicin-loaded hydrogel were determined. An injectable hydrogel was successfully formulated using 20 wt% of poloxamer 407 and 3 wt% of poloxamer 188. This system became fluid at room temperature (25 °C) in the presence of deionized water; at human body temperature (37 °C), it changed to a gel-like state. The gelation time was approximately 95 seconds. The poloxamer hydrogels showed no cytotoxicity to L929 cells after seven days of culturing. A poloxamer hydrogel loaded with gentamicin sulfate, an antibiotic, was studied for its antibacterial properties against E. coli, B. cereus, S. aureus, and MRSA using gentamicin solution as the control. The results showed that the gentamicin-loaded poloxamer hydrogel inhibited bacteria from the first hour of testing. Moreover, the zone of inhibition of the gentamicin-loaded poloxamer hydrogel was larger than that of the gentamicin solution for a similar concentration of gentamicin sulfate. It can be a potent drug carrier for infected cavity wounds.