Enhancement of Dissolution Rate of Ramipril Tablets by Solid Dispersion Technique

Ramipril is an ACE inhibitor mainly used for management of mild to severe hypertension and myocardial infarction. The poor solubility and wettability of Ramipril leads to poor dissolution and hence showing variations in bioavailability.The present study is aimed to improve the physicochemical properties of the drug using solid dispersion [SD] techniques. Solid dispersions [SDs] of ramipril were prepared with different polymers or carriers such as polyvinylpyrrolidone (PVP K25, PVP K30 and PVP K90), polyethylene glycol (PEG 4000 and PEG 6000) at three drug : carrier ratios (1:1), (1:2) and (1:3). Different methods such as melting and kneading methods were used. The formulations were characterized by X-Ray Diffractometry studies, Fourier transform infrared spectroscopy and in vitro dissolution rate studies. In contrast to the slow dissolution rate of pure Ramipril, the dispersion of the drug in the PEG4000 or 6000 considerably enhanced the dissolution rate. Furthermore; Ramipril 10 mg immediate release tablets prepared in a ratio of 1:1 (drug: carrier) by the fusion method has been resulted in an acceptable dissolution results; 91% and 97% for ramiprilPEG4000 and ramipril-PEG6000 respectively.