Design and development of a self-nanoemulsifying drug delivery system for telmisartan for oral drug delivery

Telmisartan (TEL) is an angiotensin II receptor blocker (ARB) antihypertensive agent. The aim of the present investigation was to develop a self-nanoemulsifying drug delivery system (SNEDDS) to enhance the oral bioavailability of poorly water soluble TEL. The solubility of TEL in various oils was determined to identify the oil phase of a SNEDDS. Various surfactants and co-surfactants were screened for their ability to emulsify the selected oil. Pseudoternary phase diagrams were constructed to identify the efficient self-emulsifying region. A SNEDDS was further evaluated for its percentage transmittance, emulsification time, drug content, phase separation, dilution, droplet size, zeta potential, pH, refractive index, and viscosity. The developed SNEDDS formulation contained TEL (20 mg), Tween(®) 20 (43.33%w/w), Carbitol(®) (21.67%w/w), and Acrysol(®) EL 135 (32%w/w). The optimized formulation of the TEL-loaded SNEDDS exhibited a complete in vitro drug release in 15 min as compared with the plain drug, which had a limited dissolution rate. It was also compared with the pure drug suspension by oral administration in male Wister rats. The in vivo study exhibited a 7.5-fold increase in the oral bioavailability of TEL from the SNEDDS compared with the pure drug suspension. These results suggest the potential use of the SNEDDS to improve the dissolution and oral bioavailability of poorly water soluble TEL.