The aim of this study was to prepare binary supercooled liquid (SCL) by intermolecular interaction and apply this formulation to transdermal drug delivery. Ketoprofen (KET) and ethenzamide (ETH) were selected as binary SCL component. Thermal analysis of physical mixtures of KET and ETH showed decreases in melting points and glass transition below room temperature, thereby indicating formation of KET-ETH SCL. Intermolecular interactions between KET and ETH in the SCL were evaluated from Fourier transform (FT)-IR spectra. KET-ETH SCL maintained SCL state at 25°C with silica gel over 31 d and at 40°C/89% relative humidity (RH) over 7 d. KET SCL and KET-ETH SCL showed similar permeability of KET for hairless mice skin, which was two-fold higher than that of KET aqueous suspension. Our findings suggest that the SCL state could enhance the skin permeation of drugs and the binary SCL formed by intermolecular interaction could also improve the stability of the SCL. The binary SCL system could become a new drug form for transdermal drug delivery.
Keywords: co-amorphous; ethenzamide; ketoprofen; supercooled liquid; transdermal drug delivery.