Preparation of oral nanoemulsion drug delivery system loaded with punicalagin: in vitro antibacterial activity, drug release, and cell safety studies

The objective of the present study was to develop a W/O/W nanoemulsion (NE) drug delivery system loaded with punicalagin (PGN) for oral delivery and evaluate its potential in antibacterial therapy. The W/O/W PGN-NE was prepared using a two-step process by combining ultrasonic with high-energy emulsification and subsequently characterized by its droplet size, zeta potential, and morphology. The PGN-NE was further evaluated for its pH, in vitro antibacterial activity, drug release property, and cytotoxicity. The results indicated the formation of spherical, nano-sized globules of PGN-NE had a mean particle size of 45.53 ± 2.2 nm, with a PDI value of 0.22 ± 0.028, zeta potential was −4.67 ± 0.88 mV, and pH value was 5.8. In vitro antibacterial activity studies showed a significantly higher antibacterial activity of PGN-NE in comparison to free PGN, suggesting that NE can effectively improve the antibacterial effect of natural pharmaceuticals. The drug release assay demonstrated that PGN was slowly released from the NE preparation and absorbed, helping to prolong the potency and improve the bioavailability of PGN. Cytotoxicity testing showed that PGN had reduced toxicity when encapsulated in NE. Thus, the developed NE formulation of PNG exhibited a greater potential for the slow-release effect delivery and in the treatment of microbial infections with favorable safety profile.

Graphical abstract

Micromorphology of W/O/W PGN nanoemulsion

The W/O/W PGN-NE are uniform in size and non-adhesive, with a size distribution of 28.214 to 141.772 nm and a mean size of 45.53 ± 2.2 nm, respectively, with a PDI value of 0.22 ± 0.028.