Combination of microneedles and microemulsions to increase celecoxib topical delivery for potential application in chemoprevention of breast cancer.

In spite of the high incidence of breast cancer worldwide, there are few strategies for its chemoprevention, and they have limited adherence mainly due to their serious adverse effects. As a new approach for local breast cancer chemoprevention, we developed and optimized microemulsions for topical delivery of celecoxib to the breast skin, and evaluated their combination with microneedles to improve drug penetration for localization in the mammary tissue. Microemulsions containing water at 15% (ME-15), 29% (ME-29) and 60% (ME-60) were obtained and characterized. They were isotropic, displayed Newtonian behavior and particle size smaller than 100 nm. ME-15 and ME-29 increased transepidermal water loss (TEWL) compared to ME-60, and displayed stronger vascular toxicity, evidenced by hemorrhage and lysis in HET-CAM assays. ME-60 was more efficacious at increasing celecoxib cutaneous and percutaneous delivery (1.3-4-fold). Increasing the number of microneedle roller applications from 1 to 8 increased the number of skin punctures and TEWL; its association with ME-60 promoted no further increase in TEWL, but improved (1.6-4-fold) celecoxib cutaneous and percutaneous delivery. Microemulsion incorporation reduced celecoxib IC50 in MCF-7 cells (3.3-fold), suggesting that presence of formulation components in the mammary tissue might improve drug cytotoxicity.