Solubility Determination and Thermodynamic Model Analysis of Adefovir in Different Solvents from 278.15 to 328.15 K

Abstract

In this experiment, we used eight pure solvents and three binary solvents to measure the solubility data of adefovir (AF) in the temperature range of 278.15–323.15 K. To ensure the accuracy of these data, we employed thermodynamic models to fit the data and assess their accuracy. We observed that the solubility of adefovir in all solvents increased with the temperature. Among the pure solvents, DMF exhibited the highest solubility of adefovir, while the solubility of adefovir in toluene was the lowest. The solubility of adefovir improved as the positive solvent’s molar fraction increased in the binary solvent mixtures. All five models effectively fitted the solubility data, and the reliability of the results was confirmed by comparing the relative average deviation (RAD) and the root-mean-square deviation (RMSD) for each model. In conclusion, the modified Apelblat model was found to be more effective for pure solvents, while the CNIBS/R–K model demonstrated superior performance for binary solvents. Additionally, analysis of the pure solvent parameters using the KAT-LSER model revealed that the hydrogen bonding alkalinity of the solvents was the main factor influencing the solubility of adefovir in the solvent.