Microemulsions as nanocarriers for oral and transdermal administration of enoxaparin

Low and high molecular weight heparins are essential anticoagulant drugs and usually given subcutaneously. In this research, the oral and transdermal absorption of enoxaparin via nonionic microemulsions as liquid nanocarriers was evaluated. The enoxaparin was incorporated into different nonionic inverted microemulsions (MEs). The microemulsions were characterized for their droplets' size, rheological properties and drug encapsulation. In addition, the flux of the loaded enoxaparin MEs was assessed using Franz diffusion cells. Furthermore, the efficacy of these enoxaparin-loaded MEs was evaluated in rats after oral administration and transdermal application in comparison to the subcutaneous solution. The results showed that these formulations have a droplets’ size in the range of 200 nm or less, and had Newtonian viscosity. The fitting of penetration data using Franz diffusion cells revealed a flux of enoxaparin through the epidermis as high as 3.47 ± 0.85 mg/cm2 h. Moreover, the recorded response after the oral administration and transdermal application showed a clear increase in the clotting time; and this response changed with time. Furthermore, the transdermal application showed a higher bioavailability in comparison to the oral administration. This novel in vitro and in vivo research disclosed the possibility of using nonionic microemulsions to facilitate the oral and noninvasive transdermal applications of enoxaparin.