Solubility and thermodynamic function of lornoxicam in (PEG-400 + water) mixtures at different temperatures

The present study was undertaken to determine the solubility and thermodynamic function of a poorly soluble drug lornoxicam (LNX) in various [polyethylene glycol-400 (PEG-400) + water] mixtures at five different temperatures from T = (298.15 to 323.15) K and atmospheric pressure. The measured solubilities of LNX were correlated with three different mathematical models which showed good correlation of experimental solubilities of LNX with calculated ones. The mole fraction solubility of LNX was found to be highest in pure PEG-400 (1.71 × 10− 2 at T = 323.15 K) and lowest in pure water (2.90 × 10− 6 at T = 298.15 K) at all five different temperatures investigated. Thermodynamic function of LNX in different (PEG-400 + water) mixtures was recorded as an endothermic, spontaneous and entropy driven. These results indicated that PEG-400 could be utilized as a good solvent for solubilization and stabilization of LNX in an aqueous media.