Experimental solubility of omeprazole in pure and ethanol-modified subcritical water.

The current research aimed to study and measure the solubility of omeprazole (used to treat and reduce stomach acid) for the first time in pure subcritical and ethanol-modified water. These tests have been performed in the 25-130 °C temperature range and constant pressure of 20 bar with the use of 0-10% ethanol weight as the cosolvent. The solubility of omeprazole in subcritical water ranged from 0.0697 × 10 to 5.843 × 10 mol fraction at temperatures from 25 to 130 °C, respectively. The highest solubility was obtained at 130 °C with a 10% ethanol weight as the cosolvent, which is indicative of a significant trend of improvement in omeprazole solubility with the increase in temperature and the use of ethanol cosolvent in various weight percentages. The solubility experimental data obtained were fitted using the semi-experimental and modified Apelblat linear model, and the findings revealed an excellent correlation between the experimental data and the data received from the linear and modified Apelblat model. Also, at the 25-130 °C temperature range, no degradation, phase transition, or other changes in the structure and physical state of the drug were observed.