Volumetric-acoustic investigations of antihypertensive drug in aqueous acetaminophen system

Abstract

Captopril is an antihypertensive drug used to lower the blood pressure in living organisms. In order to arbitrate and understand the synergy between antihypertensive drug viz., captopril and antipyretic drug acetaminophen in aqueous system, the density and sound velocity at different temperatures (293.15 to 318.15) K with temperature interval of 5 K were measured using Anton Paar density sound velocity meter (DSA5000M). The experimental measured data were further used to calculate volumetric and acoustic parameters such as apparent and partial molar volume, apparent and partial molar isentropic compressibility, partial molar expansibility, Hepler’s constant, compressibility hydration number, and intermolecular free length. Positive values of apparent molar volume (ϕv) and negative values of apparent and partial molar compressibility (ϕk and ϕko) of captopril in water and aqueous acetaminophen solution has been shown strong intermolecular interactions in solutions. Negative values of Hepler's constant indicate the structure breaking behavior of drug in water.