Vehicle effect on topical drug delivery. I. Influence of glycols and drug concentration on skin transport
Møllgaard, B.; Hoelgaard, A.
Acta Pharmaceutica Suecica 20(6): 433-442
1983
ISSN/ISBN: 0001-6675 PMID: 6675422 Document Number: 212052
Cutaneous permeation of estradiol and metronidazole was determined simultaneously using excised human skin mounted in open diffusion cells. The effect of vehicles consisting of propylene glycol-glycerol mixtures and ethylene glycol-polyethylene glycol 400 mixtures, and of the drug dose on the apparent steady state flux of the 2 drugs was determined in 32 factorially designed experiments. Based on the resulting data, a 2nd order multiple regression model was generated and its significance, together with the significance of the regression coefficients, was tested by analysis of variance. It appeared that the permeation rate of both drugs was highly positively correlated with the weight fraction of propylene glycol and ethylene glycol, respectively. The significant effect of dose could be ascribed to a linear dependence between the actual amount of drug permeating and the drug dosage applied. Apparently approaching the saturation concentration of drug in the vehicles did not affect the permeation rate.