Purpose: To develop microemulsions containing atorvastatin for transdermal application, which will improve the bioavailability and reduce the side effects associated with the oral administration of atorvastatin.Methods: Atorvastatin-loaded microemulsions (MEs) were developed using tween 80 as a nonionic surfactant, isopropyl myristate, polyethylene glycol 400 and dimethyl sulfoxide. Their droplets’ size, and rheological properties were estimated, with the diffusion through the rat’s skin being evaluated using Franz diffusion cells. Furthermore, the in vivo transdermal and oral bioavailability, as well as the toxicity of formulation, were assessed in rats.Results: The results showed that the MEs have a droplet size lower than 100 nm and low Newtonian viscosity. In addition, a flux rate of atorvastatin as high as 10.078 μg/cm2.h was achieved after the loading of the MEs. The in vivo transdermal application maintained a steady state concentration of 1.02μg/mL for 48 h, in comparison to a maximum concentration of 7.7 μg/mL after 2.74 h following oral administration at the same dosing level. Moreover, the transdermally treated rats did not elicit skin irritation.Conclusion: The developed atorvastatin MEs for transdermal application delivers the drug to achieve a controlled plasma level, as well as reduce dosing frequency and toxicity in rats when compared to oral administration. Therefore, the formulation has a potential for development for use in humans.

Purpose: To develop microemulsions containing atorvastatin for transdermal application, which will improve the bioavailability and reduce the side effects associated with the oral administration of atorvastatin.Methods: Atorvastatin-loaded microemulsions (MEs) were developed using tween 80 as a nonionic surfactant, isopropyl myristate, polyethylene glycol 400 and dimethyl sulfoxide. Their droplets’ size, and rheological properties were estimated, with the diffusion through the rat’s skin being evaluated using Franz diffusion cells. Furthermore, the in vivo transdermal and oral bioavailability, as well as the toxicity of formulation, were assessed in rats.Results: The results showed that the MEs have a droplet size lower than 100 nm and low Newtonian viscosity. In addition, a flux rate of atorvastatin as high as 10.078 μg/cm2.h was achieved after the loading of the MEs. The in vivo transdermal application maintained a steady state concentration of 1.02μg/mL for 48 h, in comparison to a maximum concentration of 7.7 μg/mL after 2.74 h following oral administration at the same dosing level. Moreover, the transdermally treated rats did not elicit skin irritation.Conclusion: The developed atorvastatin MEs for transdermal application delivers the drug to achieve a controlled plasma level, as well as reduce dosing frequency and toxicity in rats when compared to oral administration. Therefore, the formulation has a potential for development for use in humans.