Total and partial solubility parameters prediction: Lornoxicam in individual solvents

Abstract

BackgroundThe solubility behavior of lornoxicam was used to predict its solubility parameter in untested solvents of several chemical classes varying from nonpolar to highly polar in nature. MethodsSupersaturated solution of lornoxicam was shaken in a water bath for 72 h at 25 °C. The drug content was determined after attaining the equilibrium. The extended Hansen's method was applied for analyzing the solubility datum and partial solubility parameters were obtained for knowing the solute–solvent interaction. The method applied regression analysis of logarithm of the experimental mole fraction solubility of the drug against the partial solubility parameters of the solvent. ResultsA correlation was up to 90% using Flory–Huggins size correction term B, in the prediction of lornoxicam solubility. The four parameter approach involving proton-donor and proton-acceptor parameters was used in fitting the solubility data (R2 = 84%). Further, the ‘B’ term coupled with four-parameter approach was result in 2% improved in the correlation. The total solubility parameter obtained by this method was 11.10 H, which was closer to the value obtained by Van Krevelan method (11.69 H). ConclusionThe ensuing partial solubility parameters obtained are δ2d = 9.03 H; δ2P = 5.40 H; δ2a = 3.27 H; δ2b = 1.93 H gives insights into the interaction capabilities of the drug. As δ2a > δ2b, proves lornoxicam is a Lewis acid i.e. a better proton donor which are in favor with its chemical structure. By various methods of datum analysis, the solubility parameter of lornoxicam was consigned at 11.10 H.