Using a Laser Monitoring Technique for Dissolution and Thermodynamic Study of Celecoxib in 2-Propanol and Propylene Glycol Mixtures

In the current work, a laser monitoring technique was used to study dissolution and solubility of celecoxib (CBX) in 2-propanol and propylene glycol mixtures at temperatures of 293.2–313.2 K. The solubility data were fitted to mathematical models, i.e., the van’t Hoff model, the mixture surface model, the Jouyban-Acree and Jouyban-Acree-van’t Hoff equations, and the modified Wilson model. Model accuracy was evaluated by mean relative deviation (MRD%) for back-calculated solubility values. The thermodynamic behavior of CBX dissolution was evaluated according to the van’t Hoff and Gibbs equations. CBX exhibited maximum solubility in 2-propanol with a mass fraction of 0.8 at all temperatures. CBX dissolution was identified as an endothermic and enthalpy-driven process, which was more favorable in mixtures with high drug solubilizing capacity. The various models described solubility data from the laser monitoring technique adequately, and the studied cosolvent mixtures have the potential to be used in analytical pharmaceutical development or as intermediate bulk solutions for CBX products.