Three-dimensional solubility parameters and their use in characterising the permeation of drugs through the skin.

The physico-chemical properties of drug substances are major determinants of their transdermal absorption. In the present study the concept of the three-dimensional solubility parameters of Hansen was applied in conjunction with the Bagley projection to describe the permeation of drugs and model substances through the skin. Drug permeation data from the literature were compared with the calculated solubility parameters of the drugs. It was demonstrated that the permeation of drugs can be estimated by their position in the Bagley diagram. There is a linear correlation between the logarithm of the skin permeation of drugs and the exchange cohesive energy for the steroids testosterone, progesterone, hydrocortisone acetate, corticosterone, cortisone, and dexamethasone. A linear correlation can be confirmed for the permeation of glyceryl trinitrate, digitoxin, oestradiol, scopolamine, atropine, diethylcarbamazine, fentanyl, and chlorpheniramine. In the case of morphine, codeine, sufentanil, meperidine and hydromorphone there is a linear relationship, too.