Enhancement of Solubility and Dissolution Rate of Olmesartan Medoxomil by Solid Dispersion TechniqueAuthor(s): A. Abdul Hasan Sathali and J. Jayalakshmi
The present study involved preparation of solid dispersions of Olmesartan medoxomil to improve the aqueous solubility and dissolution rate in order to enhance bioavailability. Olmesartan is a BCS Class II anti-hypertensive drug, having low aqueous solubility and low bioavailability of 26%. In the present study, solid dispersions of Olmesartan with different carriers like poly ethylene glycol 4000 (PEG 4000), HPMC K4, HPMC K100, Poloxamer-407 and crospovidone in different ratios (1 : 1, 1 : 2, 1 : 4, 1 : 6) were prepared by melting, solvent evaporation and kneading methods. The formulations were further characterized for percentage yield, drug content, in vitro release study, solubility study and stability study. In vitro release studies revealed that the solid dispersions prepared by solvent evaporation method showed faster drug release than melting and kneading method. Solid dispersion containing crospovidone (1 : 4) was considered as the best formulation because of its faster drug release among all formulations. Differential scanning calorimetry (DSC) and infrared spectroscopy (IR) studies revealed that no interactions exist between drug and polymer. Powder X-ray diffraction studies showed a significant decrease in crystalline nature of drug in solid dispersions. In conclusion, solid dispersions of Olmesartan in crospovidone (1:4) have shown to be a promising approach to enhance the bioavailability of Olmesartan.