Phenomenological analysis of drug transport through stratum corneum

To illustrates the phenomenological relationship of drug permeable process through SC and provides theory and method for research of transdermal drug delivery (TDD). Supposing the system of side-by-side permeation chambers is constant temperature, no chemical reaction, solution with non-viscosity, only two species and local equilibrium, determine mass flow and volume flow, as well as physical force and surface force. Tinidazole as pattern drug, the experiment was carried out by three groups of control (passive) and drug (electric pulse protocol including: pulse voltage V₀ = 94-400 V, pulse rate R = 4 ppm, pulse number N = 50, storage capacitor C = 4.7, 22, 47, 100 μF. Results show that: (1) Not only drug transdermal permeation, but also volume loss of solution occurs in the system; (2) According to experimental data, phenomenological coefficient is time variable, the action of surface force on mass flow and physical force on physical flow decreases as time expands; (3) Volume flow may be generated by velocity gradient arising from solution convection on the surface of stratum corneum (SC). Therefore, the permeation chamber is a non-linear and time-variable system.