Lipid Microspheres for Topical Delivery of Norfloxacin: Development and Evaluation.

Objective: The objective of the present study is the development and evaluation of Norfloxacin lipid microspheres as topical gels for adjunct therapy to overcome complex clinical challenges presented by moist, thermally coagulated burn wounds.

Methods: Norfloxacin-loaded lipid microspheres were prepared using the melt diffusion technique with Compritol ATO HD5, stearic acid, Tween 20, Span 80, and Transcutol P, and were incorporated into topical gels formulated with Carbopol 971P NF.

Results: Lipid microspheres exhibited an average size of 65.22+23.39 μm and a drug entrapment efficiency of 81.58 ± 0.81%. Scanning electron microscopy confirmed spherical particle morphology, while differential scanning calorimetry indicated the amorphous nature of norfloxacin within the microspheres. In vitro studies demonstrated extended release of norfloxacin, with 72.33 ± 1.46% released from microspheres and 63.18 ± 1.24% from topical gels after 8 hours. Ex vivo studies revealed 28.16 ± 0.63% of norfloxacin permeating through second-degree burnt porcine skin and 21.12 ± 1.38% through intact porcine skin after 8 hours from topical gels. In vitro antibacterial studies indicated a lower MIC₉₀ of lipid microspheres compared to the pure drug.

Conclusions: The approach shows promise in enhancing drug availability for managing burn wound complexities through improved solubility, extended release, and localized delivery. However, preclinical, clinical, and regulatory evaluations are required to establish the utility of the proposed approach. Further investigation into its application for other types of chronic or infected wounds could broaden its therapeutic potential.