Effects of Sodium Salts of Fatty Acids and Their Derivatives on Skin Permeation of Cromolyn Sodium

Atopic dermatitis is a chronic inflammatory disorder with rising prevalence. The safety concerns over usually used steroids are driving the need for developing an effective atopic dermatitis treatment. The use of therapeutic agents such as cromolyn sodium (CS) is suggested. However, due to its physicochemical properties, CS permeation across the skin is a challenge. The aim of this study was to investigate the effect of sodium salts of fatty acids or their derivatives with varied carbon chain lengths as potential enhancers on the skin permeation of CS. These included sodium caprylate, salcaprozate sodium, sodium decanoate, sodium palmitate, and sodium oleate dissolved in propylene glycol along with CS (4% w/w). In vitro permeation of the formulations across the dermatomed porcine ear skin was investigated over 24 h using Franz Diffusion cells. The amount of CS permeation from propylene glycol was 5.54 ± 1.06 µg/cm 2 after 24 h. Initial screening of enhancers (enhancer: drug::1:1) showed enhancement in permeation of CS using sodium oleate and sodium caprylate, which were then investigated in higher ratio of drug: enhancer (1:2). Among all the formulations tested, sodium oleate (enhancer: drug::1:2) was observed to significantly ( p < 0.05) enhance the permeation of CS with the highest total delivery of 359.79 ± 78.92 µg/cm 2 across skin in 24 h and higher drug retention in the skin layers (153.0 ± 24.93 µg/cm 2 ) as well. Overall, sodium oleate was found to be the most effective enhancer followed by sodium caprylate for improving the topical delivery of CS. Graphical Abstract