Tenoxicam (Mobiflex) Solubility in Carbon Dioxide under Supercritical Conditions

We reported the solubility values for an active pharmaceutical ingredient (API) at different operational conditions. Tenoxicam was considered as the API model in this work, and the values of API solubility were determined between 308-338 K and 120-400 bar under supercritical conditions in CO2 as a dense solvent. The solubility measurements were performed via gravimetric technique in a designed pressure-volume-temperature (PVT) cell. The experimental data showed that the solubility of tenoxicam changes between 0.0000151 and 0.000786 mole fraction versus system pressure/temperature. The lowest tenoxicam solubility was obtained at the pressure of 120 bar and the highest temperature of 338 K. On the other hand, the highest solubility was obtained at the maximum pressure (400 bar) and temperature. As such, it turned out that the pressure had a direct influence on the API solubility such that the highest solubility was obtained at the maximum pressure. On the other hand, at low pressures, the temperature showed a negative effect on solubility. Furthermore, a theoretical study was carried out to correlate five different semiempirical correlations to the tenoxicam data, and among the employed models, the Mendez-Santiago-Teja (MST) model indicated the best performance with an AARD of 11.9%. The employed models indicated a linear trend, which can be exploited for extrapolation of the measured tenoxicam data.

Automated summary

The solubility of the active pharmaceutical ingredient, tenoxicam, was determined under supercritical conditions in CO2, showing a direct influence of pressure on solubility and a negative effect of temperature at low pressures. The Mendez-Santiago-Teja (MST) model had the best performance in correlating the solubility data, indicating a linear trend which can be utilized for data extrapolation.