Physicochemical studies of binary eutectic of ibuprofen and ketoprofen for enhanced transdermal drug delivery

Abstract

Methods: The thermodynamic, eutectic, and crystalline properties of ibuprofen and ketoprofen binary mixtures were investigated using differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD). Results: The DSC studies showed that melting point (61°C), enthalpy (11.3 kJ/mol), and entropy of fusion (33.7 J/K/mol) of the binary eutectic were significantly lower than those of the individual anti-inflammatory drugs (NSAIDs). Due to the melting-point depression and enhanced skin lipid solubility, the steady-state flux of ibuprofen and ketoprofen from preparations of the binary eutectic increased as compared to pure NSAIDs using shed snakeskin as a model membrane. The NSAID membrane flux values were calculated by flux ratio equations based on drug thermodynamic data, and compared to experimental values obtained from permeation studies. Conclusion: The proposed flux ratio equations correctly predicted flux increase.