Tablet Formulation Studies on Recrystallized Active Pharmaceutical Ingredients of Valsartan and Olmesartan Medoxomil

Both the Valsartan (VAL) and Olmesartan medoxomil (OLM) are widely prescribed anti-hypertensive agents with angiotensin II type I receptor antagonistic activity. Both VAL and OLM are type of BCS class II drugs and having a low and variable oral bioavailability.  Recrystallization of VAL and OLM from different organic solvents improved its aqueous solubility and thereby in vitro dissolution properties. In the present investigation, tablets containing Valsartan (VAL), Olmesartan medoxomil (OLM and)  recrystallized products were prepared by  direct compression method and evaluated for drug content, uniformity of weight, hardness, friability, disintegration time and dissolution properties. All the tablets fulfilled the compendial requirements with regarding to weight variation, friability and disintegration time etc for immediate release tablets.  The DP15 (drug percent dissolved at 15 min) values for V-1 (tablets of VAL), V-4 (tablets of methanol recrystallized product with crospovidone as disintegrant) and DIOVAN™ 40mg tablet formulations are 45.97,  98.95 and 82.65 respectively and V-4 formulation showed higher dissolution rate when compared to other formulations. The DP15 values of O-1(tablets of OLM), O-4 (tablets of acetonitrile recrystallized product with crospovidone as disintegrant and OLMY™ (20mg) tablet formulations are 29.25, 99.93 and 84.82 respectively. O-4 tablet formulations showed higher dissolution rate when compared to other tablet formulations. Keywords: Valsartan, Olmesartan medoxomil, Recrystallization, Aqueous solubility