Extended Hansen's solubility approach: meloxicam in individual solvents.

The solubility behaviour of meloxicam in individual solvents ranging from non-polar to highly polar was studied. For understanding the solute-solvent interactions, partial solubility parameters concept was utilized. The extended Hansen's method was used for analyzing the solubility data and for obtaining partial solubility parameters of meloxicam. The analysis was not successful though correlations were 81%. The Flory-Huggins size correction term 'B' was found to improve the prediction of solubility. The correlations were high (92%) and total solubility parameter was 11.6 H. The four-parameter approach involving proton-donor and proton-acceptor parameters was also used in fitting the solubility data. The correlations were appreciable (87%) and total solubility parameter was 11.2 H. The term 'B' combined with four-parameter approach was also used in order to improve the data, and was found to be improved the correlations (R2=0.94). This new approach may thus be used in fitting the experimental solubility data and to predict solubility behaviour of meloxicam in untested solvents. The total solubility parameter of meloxicam was assigned at 11.2 H.