Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

Although beta-lapachone is a promising drug with pharmacological activity, issues concerning its low aqueous solubility are known. The objective of this study was to measure the solubility of beta-lapachone in water and ten organic solvents at temperatures ranging from 298.15 K to 318.15 K under atmospheric pressure. The modified Apelblat model, the Buchowski-Ksiazaczak Lambda-h model, and the ideal model were used to correlate experimentally obtained solubility values. Moreover, thermodynamic analysis of beta-lapachone dissolution was performed based on experimental solubility data using the van't Hoff equation. The highest mole fraction solubility of beta-lapachone at 298.15 K was found in acetone (2.05 x 10-2), followed by acetonitrile (1.80 x 10-2), ethyl acetate (8.53 x 10-3), 1-butanol (7.43 x 10-3), 1- propanol (6.69 x 10-3), 2-butanol (5.65 x 10-3), methanol (5.40 x 10-3), ethanol (4.99 x 10-3), 2-propanol (3.76 x 10-3), propylene glycol (3.06 x 10-3), and water (2.85 x 10-6). Correlation results showed that the modified Apelblat model was more accurate than the Buchowski- Ksiazaczak Lambda-h model and the ideal model. Thermodynamic analysis indicated that beta- lapachone dissolution was endothermic and entropy-driven process in all solvents studied. Data on solubility and thermodynamic properties in various solvents obtained in this study could be helpful in formulation development, purification, and crystallization of beta-lapachone.