Topical delivery of bee venom through the skin by a water-in-oil nanoemulsion

Objective(s): Bee venom (BV) contains peptides that do not pass through healthy skin due to their high molecular weight. Nanoemulsions (NEs) are capable of facilitating drug permeation through the skin.Materials and Methods: We prepared water-in-oil (W/O) NEs containing BV with a mixture of Span 80, Tween 80, and olive oil by low energy method. Then, based on stability studies, four different NE formulations with 3, 5, 7, and 9% aqueous phase were chosen, each having different BV concentrations and characterized for their particle size, polydispersity index (PDI), viscosity, and refractive index. Afterwards, an NE preparation having 5% BV solution was used for skin permeation studies by Franz diffusion cell at three BV concentrations (i.e., 5000, 2500, and 1250 µg/ml).Results: The results showed that by increasing the percentage of BV content (from 3 to 9 %) and surfactants (from 30 to 60 %), the size of NEs decreased while increasing BV concentration at a fixed percentage of BV content, led to increase in size and PDI. Skin permeation studies showed that after 12 h, NEs could permeate approximately 10 % of initial BV through the skin, depending on BV concentration in the NE.Conclusion: The data showed that NEs could be used for topical delivery of peptides of BV through the skin.