indication

For the topical treatment of mild-to-moderate inflammatory acne vulgaris.

pharmacology

Azelaic acid is a saturated dicarboxylic acid found naturally in wheat, rye, and barley. It is a natural substance that is produced by Malassezia furfur (also known as Pityrosporum ovale), a yeast that lives on normal skin. It is effective against a number of skin conditions, such as mild to moderate acne, when applied topically in a cream formulation of 20%. It works in part by stopping the growth of skin bacteria that cause acne, and by keeping skin pores clear. Azelaic acid's antimicrobial action may be attributable to inhibition of microbial cellular protein synthesis.

mechanism of action

The exact mechanism of action of azelaic acid is not known. It is thought that azelaic acid manifests its antibacterial effects by inhibiting the synthesis of cellular protein in anaerobic and aerobic bacteria, especially Staphylococcus epidermidis and Propionibacterium acnes. In aerobic bacteria, azelaic acid reversibly inhibits several oxidoreductive enzymes including tyrosinase, mitochondrial enzymes of the respiratory chain, thioredoxin reductase, 5-alpha-reductase, and DNA polymerases. In anaerobic bacteria, azelaic acid impedes glycolysis. Along with these actions, azelaic acid also improves acne vulgaris by normalizing the keratin process and decreasing microcomedo formation. Azelaic acid may be effective against both inflamed and noninflamed lesions. Specifically, azelaic acid reduces the thickness of the stratum corneum, shrinks keratohyalin granules by reducing the amount and distribution of filaggrin (a component of keratohyalin) in epidermal layers, and lowers the number of keratohyalin granules.

toxicity

Oral LD50 in rat: >5 g/kg

biotransformation

Mainly excreted unchanged in the urine but undergoes some b-oxidation to shorter chain dicarboxylic acids.

absorption

Approximately 4% of the topically applied azelaic acid is systemically absorbed.

half life

The observed half-lives in healthy subjects are approximately 45 minutes after oral dosing and 12 hours after topical dosing, indicating percutaneous absorption rate-limited kinetics.

route of elimination

Azelaic acid is mainly excreted unchanged in the urine, but undergoes some ß-oxidation to shorter chain dicarboxylic acids.