PHYSICOCHEMICAL CHARACTERIZATION OF THE HUMAN NAIL .1. PRESSURE SEALED APPARATUS FOR MEASURING NAIL PLATE PERMEABILITIES

[摘要] Diffusion characteristics of the nail plate are necessary in providing the baselines for rational topical management of nail infections. To develop such baselines a unique stainless steel diffusion cell was designed. The cell permits the exposure of 0.38 cm2 of nail plate to a bathing medium which is stirred by small motors mounted above the cell. The diffusion of water, methanol and ethanol at constant temperature (37.degree. C) was examined over periods up to 4 h. Average permeability coefficients of water, methanol and ethanol were determined as 16.5 .+-. 5.9 .times. 10-3 h-1, 5.6 .+-. 1.2 .times. 10-3 cm h-1 and 5.8 .+-. 3.1 .times. 10-3 cm h-1, respectively. Rates of diffusion across the nail were inversely proportional to nail thickness. Based on methanol data, nail plate barrier property appears stable for long periods of aqueous immersion.