Preparation, characterization and stability study of dutasteride loaded nanoemulsion for treatment of benign prostatic hypertrophy.

Benign prostatic hyperplasia (BPH)is the most common condition in aging men, associated with lower urinary tract symptoms. It is caused due to the augmented levels of the androgen dihydrotestosterone. Dutasteride, a 5α-Reductase inhibitor has been recommended for the treatment of BPH upon oral administration. However, long term oral administration of dutasteride may cause sexual problem in man. Therefore the main objective of this study was to develop transdermal patch having nanoemulsion gel of dutasteride in order to enhance physical and chemical stability and eliminate adverse effect of dutasteride. Optimized nanoemulsion was prepared by aqueous phase-titration method and characterized by droplet size, viscosity and refractive index. In-vitro skin permeation of dutasteride through rat abdominal skin was determined by the Franz diffusion cell.Significant increase in the steady state flux (J ss), permeability coefficient (K p) and enhancement ratio (E r) was observed in optimized nanoemulsion formulation A1 (p < 0.05). The Er of optimized nanoemulsion A1 was found to be 1.52 times with respect to control which indicates transdermal delivery may be better approach for BPH. Stability studies were performed for the period of 3 months. It was found that droplet size, viscosity and refractive index were slightly increased at refrigerator and room temperature in 3 months period. However, the changes in these parameters were not statistically significant (p ≥ 0.05). The shelf-life of optimized nanoemulsion A1 was found to be 2.18 years at room temperature. These results indicated that both physical as well as chemical stability of dutasteride in nanoemulsion formulation.