Azelaic Acid

What is azelaic acid?

Azelaic acid exists naturally in many whole grains such as wheat, rye, barley, oat seeds and sorghum (R). It is also produced by the yeast Malassezia furfur, which lives on the skin as part of the commensal flora (R).

Does azelaic acid get absorbed?

Azelaic acid is often formulated as a 20% cream or as a 15% gel. Percutaneous absorption of azelaic acid into human skin from the 20% cream formulation is 3.6% of the dermally applied dose (R). The 15% gel formulation is also effective at delivering azelaic acid to the skin (R). Studies on mice showed a 25.3% delivery into viable skin for the gel, 8 times higher than the 3.4% for the cream, despite the cream containing more azelaic acid (R). However, with both formulations the majority of the applied azelaic acid dose remained on the skin surface (R).

pH affects the penetration and absorption of azelaic acid. Compared to a pH 3.9 formulation, a formulation with a pH of 4.9 led to greater flux and retention of azelaic acid in the skin (R).

The use of a co-drug of azelaic acid and hydroquinone can improve the dermal delivery of both parent drugs, enhancing the uptake of azelaic acid by 1.4-fold and that of hydroquinone by 8.1-fold (R). The addition of 1,4-cyclohexanediol, on the other hand, retarded the penetration of azelaic acid without decreasing its retention in the skin, which may be useful for reducing potential systemic side effects (R).

What happens after azelaic acid is absorbed?

The small proportion of topically applied azelaic acid that is systematically absorbed is mainly eliminated unchanged in the urine, though some undergo mitochondrial β-oxidation to acetyl-CoA and malonyl-CoA (R).