Pharmacology: Pharmacodynamics: The antimicrobial action and a direct influence on follicular hyperkeratosis are assumed to be the basis for the therapeutic efficacy of Skinoren in acne.
Clinically, a significant reduction of the colonization density of Propionibacterium acnes and a significant reduction of the fraction of free fatty acids in the skin surface lipids is observed.
In vitro and in vivo, azelaic acid inhibits the proliferation of keratinocytes and normalizes the disturbed terminal epidermal differentiation processes in acne. In the rabbit ear model, azelaic acid accelerates the comedolysis of tetradecane-induced comedones.
Experimental results demonstrate that azelaic acid exerts a dose- and time-dependent inhibitory effect on the growth and viability of abnormal melanocytes.
The molecular mechanisms by which this is accomplished are not entirely clarified.
Currently available data suggest that the main effects of azelaic acid in the treatment of melasma are brought about by an inhibition of the DNA synthesis and/or an inhibition of the cellular respiration of the abnormal melanocytes.
Pharmacokinetics: Azelaic acid penetrates into all layers of human skin after topical application of the cream.
Penetration is faster into damaged skin than into intact skin. A total of 3.6 % of the dose applied is absorbed percutaneously after a single topical application of 1 g azelaic acid (5 g cream).
A portion of the azelaic acid absorbed through the skin is excreted in unchanged form in the urine. The remaining portion is broken down by β-oxidation into dicarboxylic acids with shorter chain length (C7, C5) which have likewise been found in the urine.