Transdermal Permeation Enhancement by Drug-Phospholipid Supramolecular Complexation

Drug delivery of highly lipophilic molecules through the transdermal route is unsuitable when systemic effect is desired. Besides the different physical and chemical approaches for permeation enhancement, a novel method has been drawn for improvement in permeation behaviour. Here, the drug molecule was supramolecularly complexed with a phospholipid molecule to form a novel chemical entity possessing improved permeation behaviour suitable for transdermal application. Curcumin (CMN) was used as model drug for preparation of Curcumin-Phospholipid Supramolecular Complex (CPSC) and was characterized by FT-IR Spectroscopy and X-Ray Diffraction Analysis. Comparative solubility study of CPSC in water and n-octanol was performed. The prepared CPSC was incorporated in polymeric matrix films of Eudragit RL100 and Eudragit RS100 and the physicochemical compatibility was studied. The permeation kinetics and permeation parameters of the films were studied against a control batch formulation loaded with uncomplexed CMN across processed excised pig ear epidermis. Skin irritation test was perfomed on rats for safety assessment of films. Analytical reports suggested supramolecular complex formation. The solubility study showed increased hydrophilicity of the prepared CPSC. The FT-IR Spectroscopy and Differential Scanning Calorimetry (DSC) confirmed no interaction between polymers and CPSC. The formulations loaded with CPSC followed zero order and Higuchi model kinetics and possessed improved permeation parameters and a good enhancement ratio against the control batch. No skin reactions were observed during the skin irritation test. The conducted experiments suggested the supramolecular phospholipid complexation to be an effective permeation enhancement technique for transdermal route.