Evaluation of Propolis and Diclofenac Sodium Eye Drops for Animals: Physicochemical Properties and In Vitro Biological Activity.

Eye diseases are common in veterinary clinical practice and are most often treated with topical ophthalmic preparations. Increasing resistance to antimicrobial agents is driving the search for safe and effective alternatives to traditional treatment methods. The aim of this study was to develop and evaluate gel-based ophthalmic formulations based on poloxamer 407 and sodium carboxymethylcellulose, containing propolis extracts and diclofenac sodium, by assessing their physical and chemical properties, antimicrobial activity, and cytotoxicity in vitro. Propolis extracts were prepared using a solvent consisting of ethanol and choline chloride, and the developed formulations were evaluated for pH, viscosity, refractive index, gelation temperature, SIRC cell viability and apoptosis, and antimicrobial activity against clinical and reference bacterial strains. The developed formulations exhibited physicochemical properties suitable for ophthalmic preparations and antimicrobial activity, particularly against Gram-positive bacteria. Most of the concentrations of the active ingredients tested were well tolerated by SIRC cells, although higher concentrations of the ethanol propolis extract caused a greater cytotoxic effect. The results obtained indicate that gelled ophthalmic formulations based on propolis extracts and diclofenac sodium are promising for the further development of topically acting ophthalmic preparations; however, their biological efficacy and safety must be confirmed. The results obtained indicate that gelled ophthalmic formulations based on propolis extracts and diclofenac sodium are promising for the further development of topical ophthalmic preparations; however, their bioavailability and safety must be confirmed by further in vivo studies.