Development of Self Emulsifying Formulations of Poorly Soluble Naproxen for Enhanced Drug Delivery

Background: The objective of this investigation was to develop a self emulsifying drug delivery system (SEDDS) of naproxen, a poorly water soluble drug, which could improve its solubility and oral bioavailability. Methods: The recent patents on SEDDS of abiraterone acetate (WO2014/009434 A1) and tamoxifen (WO2013/0080083) helped in selecting the naproxen and excipients. Phase diagrams were constructed and the formulations were taken from the micro emulsion region. Formulations were subjected to thermodynamic stability, dispersibility and precipitation tests for optimization. Physico chemical characterization was carried out by FTIR and DSC studies. The selected SEDDS consisted of IPM+labrafac lipophile WL 1349, tween 80, PEG 400 and naproxen. The optimized formulation has globule size- 187.6 nm, zeta potential- -9.81 mv, viscosity- 1.772 cps and infinite dilution ability. Results: In vitro drug release was 98.21% and was found to be significantly different from the marketed product and plain drug. After oral administration in rats the SEDDS of naproxen showed anti inflammatory activity (69.82%) which was much improved as compared to the marketed formulation. The Cmax, AUC0t of naproxen was boosted with SEDDS to 133.63 μg/ml and 698.29 hr. μg/ml respectively. The optimized formulation was found to be stable for 6 months during stability studies conducted according to the ICH Q1A (R2) guidelines. Conclusion: Thus this developed self emulsifying drug delivery system may be a useful tool to enhance the solubility of oral poorly water soluble drug naproxen.