2.4.6. Solubility Studies

The solubility of KET from the crystalline acid form (KETH) and ZnAl-KET was measured in water, and the samples were prepared as follows: an excess of the sample (10 mg KETH and 24.10 mg of ZnAl-KET corresponding to 10 mg of KETH) was dispersed in 10 mL of ultrapure water under magnetic stirring (600 rpm) at 25 ◦C until equilibrium was achieved (48 h). The samples were filtered through a 0.45 μm nylon filter, suitably diluted, and analyzed by UV-VIS spectrophotometry.
