Development and Evaluation of Gel Incorporated Polymeric Microspheres Loaded With Neomycin Sulphate for Prolonged Topical Drug Delivery

ABSTRACTIntroduction The aim of the work was to formulate and evaluate polymeric microspheres loadedwith Neomycin Sulphate incorporated in a gel for topical drug delivery. Neomycin Sulphate wasselected because of its spectrum antibacterial activity and suitability for topical application.Methods Preformulation studies were carried out for properties, solubility, pH determination,calibration curve study and drug-excipient compatibility study by FTIR. Neomycin Sulphateloaded microspheres were prepared by emulsion solvent diffusion method and evaluated for theirphysical properties, zeta potential, surface morphology, drug entrapment efficiency and percentageyield. The gel compositions loaded with microspheres were evaluated for pH, viscosity,washability, extrudability and spreadability. In vitro drug release and antimicrobial activity werealso evaluated.Results Neomycin Sulphate was white to yellow in color, odorless, soluble in ethanol and waterand showed a pH value of 6.9. The calibration curve showed a concentration-dependent increasein absorbance in the range of 2–10 µg/mL. FTIR analysis confirmed the characteristic functionalgroups of Neomycin Sulphate and no major incompatibility was observed.The microspheresexhibited a sponge-like shape with a mean zeta potential of −9.5 mV, drug entrapment efficiencyof 94.01% and percentage yield of 84.20%. The gel compositions loaded with microspheresshowed pH values of 6.3–6.6 and viscosity of 4099–5062 cP, with satisfactory washability,extrudability and spreadability. In vitro drug release experiments showed 60.54–94.33% drugrelease after 60 min, with F5 showing the highest drug release of 94.33%. Antimicrobial screeningrevealed activity against Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli.Discussion The produced gel loaded with Neomycin Sulphate microspheres showedphysicochemical properties, effective entrapment of drug, topical application and antibacterialactivity in general.Conclusion The produced Neomycin Sulphate microsphere-loaded gel demonstrated suitablephysicochemical properties, effective drug entrapment, topical applicability and antibacterialactivity, indicating its potential as a topical drug delivery system.