Novasomal Gel for Enhanced Dermal Delivery and Antibacterial Efficacy of Cinnamic Acid

While bacterial skin infections are highly prevalent worldwide, their eradication with conventional topical medications remains highly challenging. Cinnamic acid (CA) is a naturally occurring molecule with interesting antibacterial properties, but its efficacy is hindered by poor aqueous solubility and skin permeability. To overcome these challenges, CA was encapsulated within novasomes, which are multilamellar vesicles composed of fatty acids, cholesterol, and nonionic surfactants. The novasomes were optimized using a 2³ factorial design and the optimized formulation was incorporated in a carbopol gel base and evaluated for spreadability, rheological properties, drug release, ex vivo skin permeation and deposition, and antibacterial efficacy. The optimized novasomes featured desirable properties, including high drug entrapment (94.75 ± 0.05%), nanometric particle size (123.80 ± 1.44 nm), and negative zeta potential (-36.63 ± 0.61 mV). CA novasomal gel exhibited shear-thinning behavior, coupled with thixotropic properties. It also achieved approximately 1.7-fold higher flux through rat skin compared with the free CA gel. Moreover, the novasomes showed a two-fold reduction in the minimum inhibitory concentration of the drug against E. coli compared with the drug suspension. These findings support the potential of CA novasomal gel to enhance its antibacterial activity and skin permeability, making it a promising approach for topical delivery of this naturally occurring compound.