Linalool-encapsulated alginate microspheres as anti-virulence target against wound infections using In vitro and In vivo models

Abstract

The study describes development of a drug delivery system consisting of microspheres of sodium alginate (Alg) incorporating linalool as an anti-virulence agent to treat wound infection. The linalool-Alg microspheres formulated were lyophilized and subjected for characterization, and biocompatability studies. The chemical structure, thermal stability, crystallinity, surface area, surface morphology and energy dispersive spectrum of linalool microspheres were determined by the standard methods. The Fourier Tranform-Infra Red spectra showed signature peaks of alginate and linalool between 3200 and 3400 cm−1. Thermal Gravimetric analysis data displayed thermal stability up to 700 °C with 43% of weight loss and the SEM analysis exhibited compact morphology of the linalool-Alg microspheres. The in vitro release studies showed >85% release of linalool from the microspheres into dissolution media within 12 h at 37 °C and room temperature. The linalool-Alg microspheres were compatible with fibroblasts at the tested concentrations. The treatment of Psuedomonas aeruginosa (strain PAO1) with linalool-Alg microspheres (60, 80, 100 μg/mL) resulted in significant (p < 0.01) reduction in the virulence factors such as pyocyanin (>80%), rhamnolipids (>60%) and biofilm formation (>70%). The in vivo experiments using Swiss albino mice P.aeruginosa wound infection model showed reduction in the microbial load. The linalool-Alg treatment group showed a microbial load of 1.6 × 102 CFU/mL on 7th day, whereas it was 3.78 × 106 CFU/mL in infected non-treated group. The re-epithelialization of the infected wound treated with linalool-Alg microspheres was 100% on 9th day while in the infected non-treated group 60% of healing was observed. In conclusion, linalool-Alg microspheres are effective as anti-virulent agents to treat wound infection and accelerate healing of cutaneous wounds.