Poloxamer and Chitosan-Based Gels Loaded with Benth. Extracts Containing Rosmarinic Acid for the Treatment of Ocular Infections.

Objectives: Benth. (OS) is a commonly used medicinal plant for curbing bacterial infections globally. This work aimed to fabricate poloxamer and chitosan-based gels loaded with standardized aqueous-ethanolic OS leaf extracts and investigate their antimicrobial efficacy as a potential remedy against ocular infections.

Materials And Methods: gels containing 0.5% w/v OS extract prepared using cold dispersion method were subjected to physicochemical characterization, including -release studies. Antimicrobial efficacy was tested against , and using agar diffusion method.

Results: Thin layer chromatography and high performance liquid chromatography chromatograms confirmed the presence of rosmarinic acid (RA) and sinensitin in OS extracts with same retention factor (0.26 and 0.49) and retention times (12.2 and 20.7 min) against reference standards. A homogenous brown coloured gel exhibited low viscosity as a solution and increased viscosity in gel form at ocular temperature. The optimized formulations, P7 (21% P407/4% P188), P8 (21% P407/5% P188) and F5 (1.5% chitosan and 45% -glycerophosphate) exhibited ideal ocular pH (7.27-7.46), phase transition at ocular temperature (33-37°C) and prolonged RA release up to 12 h. Formulation F5 showed an inhibition zone of 4.3 mm against .

Conclusion: Among all, formulation F5 alone exhibited modest antimicrobial activity against . OS extracts at 5% and 10% were most active against tested bacteria however, loading them into gels resulted in sedimentation. Hence, isolation of RA from OS extract is suggested before loading into formulations for a better antimicrobial activity.