Development and in vitro characterization of nanoemulsion and nanoemulsion-based gel formulations containing Heracleum persicum ethanol extract

Objective: We aimed to prepare the ethanol extract (Hp-Et) of the aerial parts of Heracleum persicum (Hp) and to determine its antioxidant capacity. We also aimed to develop nanoemulsion (NE) and NE-based gel (NEG) formulations containing this extract for topical application to the skin for wound healing and to characterize these formulations in vitro. Methods: After the preparation of Hp-Et, its antioxidant capacity was determined by FRAP, CUPRAC, and DPPH methods. Then, blank NE (B-NE) and the extract-containing NE (Hp-Et-NE) formulations were developed and in vitro characterized [morphological analysis; centrifuge test; the determination of droplet size (DtS), polydispersity index (PDI) and zeta potential; viscosity and pH measurements; FT-IR analysis]. Additionally, B-NEG and Hp-Et-NEG were prepared and in vitro characterized [viscosity and pH measurements; FT-IR analysis]. Results: DtS and zeta potential values of NE formulations were around 200 nm and -30 mV, respectively. PDI values were less than 0.4. The pH values for NE and NEG formulations were in the range of 4.63±0.01-5.73±0.01. The NE and NEG formulations showed Newtonian and pseudoplastic behaviors, respectively. Conclusion: Hp-Et-NEG exhibits the desired pseudoplastic behavior for topical application to the skin.