Release Behavior of Telmisartan/Amlodipine Combination Drug According to Polymer Type

Patients at risk for hypertension with comorbidities such as diabetes and metabolic syndrome often require two or more antihypertensive drugs to lower their blood pressure. Telmisartan and amlodipine are widely known drugs to treat hypertension. However, telmisartan suffer of poor solubility in water that makes necessary to increase its dosage to reach a sufficient therapeutic concentration. In this study, a solid dispersion containing a water-soluble polymer was prepared to make the absorption rate of telmisartan similar to that of amlodipine, a water soluble drug. As water-soluble polymers, polyvinylpyrrolidone K30, polyethylene glycol 6000, and poloxamer 407 were used. The encapsulation of the solid dispersion was analyzed by differential scanning calorimetry, Xray diffraction, and high-performance liquid chromatography. The reduced flowability of the solid dispersion was improved by a wet granulation. Scanning Electron Microscopy was used to study the morphology and the flowability was verified by measuring the angle of repose, bulk density, and tap density, and expressed by Hausner ratio and Carr index. The release behavior was confirmed by dissolution test and high-performance liquid chromatography. As result we proved that telmisartan a higher release rate when encapsulated with PVP K30. Finally, we designed a drug formulation in which amlodipine and telmisartan could be absorbed at a similar rate.