Journal of Chemical and Engineering Data, Vol.52, No.1, 256-260, 2007
Solubility of felodipine and nitrendipine in liquid and supercritical carbon dioxide by cloud point and UV spectroscopy
The solubility of two calcium channel blockers, felodipine and nitrendipine, was measured in liquid and supercritical carbon dioxide at (298, 308, and 318) K and at pressures between (80 and 250) bar. The solubilites were measured experimentally through two methods: cloud point measurements and UV absorption. At lower pressures, and hence densities, the UV method was more accurate while at higher pressures and densities the solubilities measured by both methods were basically identical. Both of these compounds showed an increase in solubility with increasing temperature and density. The experimentally determined solubility was accurately modeled using an equation, derived from association laws, which had a strong solvent density and temperature dependence.