3.2. Phase Solubility Analysis

A phase solubility study was conducted to evaluate the Ks and Ce of ternary mixtures PTS/βCD/PLF. In the present study, excessive quantities of PTS were added to aqueous solution having different concentrations of βCD from 2 mM to 8 mM and PLF (10%). The samples were placed in water shaker bath for seventy-two hours at 25 °C [60,61,62,63]. After 72 h, the supernatant from each sample was carefully pipetted out and filtered through 0.45 μm membrane filters (“Chromafil^®Xtra, Macherey-Nagel GmbH & Co. KG, Düren, Germany”). The drug content in the samples was analyzed by UV spectrophotometer at 318 nm [64,65]. According to Equation (1), a slope-based calculation of Ks can be performed using the phase solubility plot [66,67,68,69]. Equation (2) was used to calculate Ce for each sample [66,70,71]. S₀ is the equilibrium solubility of PTS in water [72,73].