Solubility and dissolution thermodynamic properties of lansoprazole in pure solvents

In this work, solubility data of lansoprazole in twelve pure solvents (methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, acetone, acetonitrile, methyl acetate, ethyl acetate, propyl acetate, butyl acetate) was measured by using a static gravimetric method at temperatures ranging from 278.15 K to 318.15 K under atmospheric pressure. The results showed that the solubility of lansoprazole increased with the increasing of temperature in the investigated temperature range. The modified Apelblat equation, the λh equation and the NRTL model were used to correlate the experimental solubility data of lansoprazole in selected solvents and the computational data showed that the Apelblat equation gave the best correlation result. Furthermore, the apparent dissolution thermodynamic properties, including Gibbs energy, entropy and enthalpy, of lansoprazole in different solvents were calculated based on the experimental solubility data and the NRTL model.