Formulation of Piperine-Loaded Nanoemulsion: In Vitro Characterization, Ex Vivo Evaluation, and Cell Viability Assessment

Piperine is an alkaloid, but its therapeutic efficacyis limiteddue to poor aqueous solubility. In this study, piperine nanoemulsionswere prepared using oleic acid (oil), Cremophore EL (surfactant),and Tween 80 (co-surfactant) using the high-energy ultrasonicationapproach. The optimal nanoemulsion (N2) was further evaluated usingtransmission electron microscopy, release, permeation, antibacterial,and cell viability studies based on minimal droplet size and maximumencapsulation efficiency. The prepared nanoemulsions (N1-N6)showed a transmittance of more than 95%, a mean droplet size between105 +/- 4.11 and 250 +/- 7.4 nm, a polydispersity index of 0.19to 0.36, and a zeta potential of -19 to -39 mV. Theoptimized nanoemulsion (N2) showed significantly improved drug releaseand permeation compared with pure piperine dispersion. The nanoemulsionswere stable in the tested media. The transmission electron microscopyimage showed a spherical and dispersed nanoemulsion droplet. The antibacterialand cell line results of piperine nanoemulsions were significantlybetter than the pure piperine dispersion. The findings suggested thatpiperine nanoemulsions may be a more advanced nanodrug delivery systemthan conventional ones.