Optimization of felodipine nanosuspensions using Full Factorial Design

The present work is aimed at the optimization of nanosuspension of felodipine, a poorly water soluble antihypertensive drug using Full factorial Design. A 3 Full factorial design using Design Expert Version 8.0.7.1was employed to study the effect of the independent variables (diffusing drug concentration and stabilizer concentration) on the dependent variables (particle size, percentage of drug released and polydispersity index). The relationship between the dependent and independent variables was further elucidated using contour plots and response surface plots.The nanosuspensions were prepared by nanoprecipitation with ultrasonnication method using ethanol as solvent and water as antisolvent. The uniform spherical shaped discrete nanoparticles were obtained in the size range of 60 300 nm. With increasing drug concentration the particle size decreases while the drug release increases. The uniformity of size indicated by polydispersity index(PI) value was found to be more dependent of stabilizer concentration as with increase in the stabilizer concentration PI decreases showing better homogeneity. The suggested optimized formulation was prepared and the observed values were comparable to the predicted values. It may be concluded that the full factorial design can be used to design and optimize the desired formulation based on different process variables. The optimized nanosuspension showed enhanced release which may lead to enhanced oral bioavailability of felodipine.