I. Penetration Through Tissue of Iodine in Different Solvents. ∗

Abstract

It has been shown by Karns 1 and by Karns, Cretcher and Beal, 2 that certain aqueous solvents for antiseptic iodine preparations are superior to those commonly in use, with respect to the iodine adsorption behavior at surfaces. This controls surface dosage, and hence becomes a very important factor in germicidal effectiveness 3 and in penetration through tissues. It has been further demonstrated by Karns 4 that the quantity of iodine absorbed on a treated surface is not a necessary function of the concentration of the iodine in the solvent used, and that surface tension plays no important rôle in this reaction. Changes in the iodine-iodide ratio of the aqueous solutions were found considerably to affect the iodine deposition.

In the work presented here, a series of iodine solutions of different concentrations and in various solvents were compared under standard conditions with respect to their rates of penetration through frog skin.

Only the fresh non-pigmented skin from the ventral body surface of large frogs between the pectoral and pelvic girdles was used, in segments about 2 cm. square, as this was found to be more nearly uniform in texture and thickness than skin from any other part of the body. It was found that any attempt to tie the skin onto containers resulted in areas of increased permeability at the sites of greatest tension, thus materially modifying the results. However, merely laying the skin, outside in, over the end of a half-inch glass tube sufficed, in the majority of cases, to seal it when inverted. Stretching was carefully avoided. The end of the tube closed with the skin was dipped in starch-iodide solution containing 0.65% of sodium chloride, a drop of the latter remaining suspended therefrom.