Synthesis and evaluation of chitosan-alginate microspheres loaded with various combinations of enrofloxacin and selected phytochemicals against pathogenic bacteria

Abstract

Enrofloxacin in combination with phytochemicals such as Curcumin (CUR), Piperin (PIP), Cinnamic acid (CIA), Caffeic acid (CAA) and Syringic acid (SYA) exhibits notable synergism against pathogenic bacteria. Chitosan-alginate encapsulated microspheres containing enrofloxacin and phytochemicals prepared and evaluated for their synergistic effect and reduction in individual agent’s disadvantages. CSALG microspheres were prepared by impregnating enrofloxacin (CS-ALG-EN) alone and in combination with respective phytochemicals such as CS-ALG-EN-CUR, CS-ALG-EN-PIP, CS-ALG-EN-CIA, CSALG-EN-CAA & CS-ALG-EN-SYA and evaluated for shape, size, loading efficacy, release kinetics of enrofloxacin and MIC of enrofloxacin along with various phytochemicals against MTCC and clinical isolate bacteria. Microspheres were spherical. When combined with phytochemicals the enrofloxacin loading efficacy decreased variably with respective phytochemicals. The % cumulative release of enrofloxacin from all microspheres was maximum at pH 1.2 and further increased at pH 6.8. CAA and SYA improved the release and CIA, CUR and PIP decreased the release of enrofloxacin from respective microspheres compared to CS-ALG-EN. The dissolution efficacy increased by addition of SYA, CAA while PIP, CIA and CUR decreased. The mean dissolution time is same in PIP, SYA, CAA while CIA showed lowest and CUR highest when compared with enrofloxacin alone loaded microspheres. The release of enrofloxacin followed korsmeyer-peppas model by following Fickian diffusion/Quasi-Fickian diffusion from spheres. The MIC of enrofloxacin significantly lowered in combination with CUR, PIP, CIA, CAA on both MTCC and clinical isolates of pathogenic bacteria. In conclusion chitosan-alginate encapsulation improved the bioavailability of enrofloxacin and phytochemicals and combination showed synergistic antibacterial effect.