Thermodynamics study of the naproxen dissolution in ethylene glycol + water cosolvent mixtures at different temperatures

Abstract

Due to the low water solubility of most drugs, improving this feature is one of the important steps in drug research and development. One of the simplest and oldest ways to increase solubility is using cosolvent. In addition, to predict their solubility in different solvent systems to save time and money can be used modeling with a variety of mathematical models provided. Aim Measurement of naproxen solubility in ethylene glycol + water system and ethanol + ethylene glycol system in the temperature range of 293.2 to 313.2 K and correlation of the obtained data with mathematical equations to predict drug solubility are the objectives of this study. Method In the shake flask method, after preparing and saturating the selected solvent mixture with the studied drug, the solutions are placed on the shaker for a certain time in the incubator at a certain temperature until the solution is saturated and reaches equilibrium. Then, after centrifugation and dilution of the solution, its absorption is taken at the maximum wavelength for the drug and the concentration of saturated solutions is obtained using the drawn calibration curve. Finally, the correlation of experimental data with computational models is examined. Results The solubility of naproxen is directly related to the increase in temperature, and in both the ethylene glycol + water and ethylene glycol + ethanol systems, the solubility increases with increasing temperature and the mass fraction of the solvent.

Conclusion The obtained data show that the solubility in the ethanol and ethylene glycol system, unlike the ethylene glycol and water system, which is exponential, follows the cosolvence effect and the highest solubility of the drug is observed in the combination of solvents