Abstract
To improve the dissolution and oral absorption of poorly water soluble drug-telmisartan, a self-nanoemulsifying system (SNES) was developed, characterized, and its relative bioavailability was compared to commercially available formulation. Safsol-218, Tween-20, and Transcutol P were chosen as oil, surfactants, and cosurfactants respectively as they show highest solubility for telmisartan. The solubility of drug was further improved by adding sodium hydroxide (0.67%). The droplet size of the optimized emulsion was also evaluated and was observed to be in nano range. The dissolution of drug was rapid in simulated gastric fluid (pH 1.2) as well as in simulated intestinal fluid (pH 6.8) and was found to be pH independent. The pharmacokinetic parameters (AUC0→t ± SD, Cmax, and Tmax) of optimized formulation of telmisartan after oral administration as SNES were compared with oral tablet and API suspension of drug. The results showed a 4.34-fold increase in oral bioavailability of drug in comparison to tablet. The results demonstrate that SNES composed of Sefsol-218, Tween-20, and Transcutol P substantially enhanced the bioavailability of telmisartan. Further, it showed highly significant fall (p < 0.001) in mean blood pressure of hypertensive rats for 48 hours. Thus, our study provides a useful oral dosage form for telmisartan.
Acknowledgements
The authors are very grateful to Gattefosse (Saint Priest, Cedex France) for providing the free gift samples of surfactants. J. A. acknowledges University Grants Commission for providing financial assistance for the project.
Notes
a Time of peak concentration.
b Peak of maximum concentration.
c Area under the concentration time profile curve until last observation.
d Relative bioavailability of formulations.
e With respect to API.