Abstract
The aim of this study was to evaluate the two different viscosity grades of Polyethylene oxide (PEO WSR 1105 and PEO WSR COAGULANT) as compression coating polymers in chronotherapy of hypertension. Solubility enhancement of the olmesartan medoxomil was performed by incorporating disintegrant (crospovidone) and surfactant (Poloxamer 188) in the core formulation and were compressed to tablets by direct compression technique. Compression coating technique involves the preparation of core tablet which contains drug and compression coating of hydrophilic or hydrophobic rate controlling polymers around the coat. Tablets were evaluated for physico-chemical characteristics as per the methods described in the Indian Pharmacopoeia and United States Pharmacopoeia. Significant increase in the solubility of the olmesartan medoxomil was observed compared to pure drug further, the drug release of the optimized formulation was comparable to commercial tablet (OLMEZEST). Desired release profile corresponding to formulations designed for chronotherapy of hypertension was achieved with both grades of polyethylene oxide. Less concentration of PEO WSR COAGULANT (high viscosity) was required compared to PEO WSR 1105 (low viscosity) to achieve the desired release profile, indicating the effect of viscosity on drug release retarding capacity of polymer. FTIR studies of the optimized formulation had shown no interaction between the drug and polymers.
