Solubility Data, Solubility Parameters and Thermodynamic Behavior of an Antiviral Drug Emtricitabine in Different Pure Solvents: Molecular Understanding of Solubility and Dissolution.

The solubility values, various Hansen solubility parameters (HSPs) and thermodynamic behavior of emtricitabine (ECT) in twelve different pure solvents (PS) were estimated using various experimental as well as computational methods. Experimental solubility values (xe) of ECT in twelve different PS were obtained at T = 298.2 K to 318.2 K and p = 0.1 MPa. The xe values of ECT were correlated by "van't Hoff, Apelblat and Buchowski-Ksiazaczak λh models". Various HSPs for ECT and twelve different PS were also calculated using "HSPiP software". The xe values of ECT were estimated maximum in polyethylene glycol-400 (PEG-400; 1.41 × 10-1), followed by ethylene glycol, Transcutol-HP, propylene glycol, methanol, water, isopropanol, ethanol, 1-butanol, dimethyl sulfoxide, 2-butanol and EA (1.28 × 10-3) at T = 318.2 K. "Apparent thermodynamic analysis" showed an "endothermic and entropy-driven dissolution" of ECT. Overall, PEG-400 was found as the best/ideal solvent for solubility/miscibility of ECT compared to other solvents studied.