Apparent Molal Volumes of Lidocaine−HCl and Procaine−HCl in Aqueous Solution as a Function of Temperature

Abstract

Apparent molal volumes of two local anesthetics, lidocaine HCl and procaine HCl, in water at (298.15, 303.15, and 310.15) K have been measured in the concentration range from (0.01 to 0.1) mol·kg-1. The densities were obtained with a magnetic float densimeter. The concentration dependence of Vφ has been calculated using the Redlich and Meyer equation. The values of apparent molal volumes at infinite dilution, , the empirical constants BV, and the partial molal expansibilities, , were calculated. The results are interpreted in terms of competitive effects between electrostriction and hydrophobic solvation.