D. A. Bhagwat, J. I. D’Souza
ABSTRACT
Nearly 40% of new drug candidates exhibit low solubility in water, which leads to poor oral bioavailability, high intra- and inter-subject variability and lack of dose proportionality. Various approaches should use to improve the dissolution rate of the drug. Among them, Self micro emulsifying drug delivery systems (SMEDDS) have shown great promise for enhancing bioavailability of low solubility compounds. Conventional SMEDDS are normally prepared in a liquid dosage form that can be administered in soft gelatin capsules, which have some disadvantages especially in the manufacturing process. Solid-SMEDDS prepared by solidification of liquid/semi-solid self emulsifying ingredients into powders in order to create solid dosage forms.
The main objective of the study was to develop and evaluate an optimal S-SMEDDS formulation containing Telmisartan by spray drying technique. In present study solubility of Telmisartan was determined in various oil, surfactant and co-surfactant. Pseudoternary phase diagrams were used to evaluate the microemulsification existence area. Three component SMEDDS formulation were established which contain Polyoxyl 35 castor oil, Tween 80 and Carbitol as oil, surfactant and co-surfactant respectively. Selected combinations were exposed to spray drying using water soluble maltodextrin as solid carrier. S-SMEDDS formulations were tested for microemulsifying properties and for solid state characterization. The in-vitro dissolution studies of S-SMEDDS of Telmisartan filled into hard gelatin capsule and marketed formulation NEWTEL 20®was carried out.
Results showed that the mean droplet size of all reconstituted S-SMEDDS were very low and all were found to be in the nanometric range (<100 nm). Drug releases from S- SMEDDS formulations were found to be significantly higher as compared with that of pure drug. Thus study concluded with S-SMEDDS provides useful solid dosage form to improve solubility and dissolution rate of Telmisartan and concomitantly bioavailability.
Keywords: Solid self micro emulsifying drug delivery system, spray drying, oral bioavailability