Development of rivaroxaban microemulsion-based hydrogel for transdermal treatment and prevention of venous thromboembolism

We have developed a microemulsion (ME)-based hydrogel, containing propylene glycol, Azone (R), Labrasol (R), isobutanol and water (20:3:18:3:56), for the transdermal delivery of rivaroxaban (RVX). Formulation ME-1:RVX, which was loaded with 0.3 mg/g of RVX, presented as a clear, homogenous fluid with a droplet size of 82.01 +/- 6.32 nm and a PdI of 0.207 +/- 0.01. To provide gelation properties, 20 % (w/w) of Plumnic (R) F-127 was added to ME-1:RVX to generate formulation PME-1a. An added benefit was an increased capacity for RVX to 0.4 mg/g (formulation PME-1b). PME-1b displayed spherical droplets with a nanoscale diameter as observed by Transmission Electron Microscopy. The release of RVX from PME-1b was 20.71 +/- 0.76 mu g/cm(2) with a permeation through pig epidermis of 18.32 +/- 8.87 mu g/cm(2) as measured in a Franz Cell for 24 h. PME-1b presented a pseudoplastic behavior, pH value compatible with the skin and good stability over 60 days at mom and elevated temperatures. The prothrombin time was assessed for each concentration of RVX obtained in the permeation assay and each demonstrated a relevant anticoagulant activity. PME-lb also presented no cytotoxicity against HaCaT cells. Utilizing GastroPlus (R) software, an in silico analysis was performed to simulate the delivery of PME-1b through a transdermal system that suggested a minimum dose of RVX for the treatment and prevention of venous thromboembolism could be achieved with an 8 h administration regimen. These results suggest that PME-1b is a promising transdermal formulation for the effective delivery of RVX that could be a viable alternative for the treatment and prevention of venous thromboembolism.