Injectable vancomycin loaded hyaluronic acid-chitosan hydrogel for the treatment of Staphylococcus aureus septic arthritis

Staphylococcus aureus (S. aureus) is a Gram positive opportunistic pathogen and a major cause for bacterial septic arthritis. Vancomycin is the preferred antibiotic for the treatment of methicillin resistance S. aureus septic arthritis. Patients undergoing vancomycin treatment need to be hospitalized and their serum vancomycin level should be monitored, as increase in vancomycin concentration in serum may lead to hepatotoxicity. To overcome vancomycin mediated cytotoxicity, we have prepared a local injectable delivery system by incorporating vancomycin into hyaluronic acid (HA)-chitosan (van-HA-chitosan) hydrogel. The prepared van-HA-chitosan hydrogel was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and rheometer. The vanHA-chitosan hydrogel is injectable, has shear thinning behaviour; and is hemo- and cyto-compatible. In vitro drug release assay showed that 95 % of vancomycin was released from the hydrogel in 8 days. Under in vitro conditions the load of S. aureus decreased from 6.4 Log10 CFU/ml to 3.5 Log10 CFU/ml when treated with vanHA-chitosan hydrogel for 6 h. Significant decrease in bacterial counts was observed when S. aureus infected synovial fluid and bone samples were treated with van-HA-chitosan hydrogel. Our results suggest that the prepared van-HA-chitosan could be used for the treatment of septic arthritis caused by S. aureus.