CAS 81103-11-9

General Information

Clarithromycin belongs to a class of molecules termed macrolide antibiotics and is used for the treatment of bacterial infections such as pneumonia, bronchitis, and ear, sinus, skin, and throat infections. It is also used for the prophylaxis and treatment of disseminated Mycobacterium avium complex (MAC) infections (a bacterial infection that commonly affects patients with HIV) and in combination with other drugs to target the bacterium H. pylori (a bacterium that causes duodenal ulcers). Clarithromycin inhibits the growth of bacteria by targeting protein synthesis.


Clarithromycin became FDA approved for the treatment of certain bacterial infections under the trade name Biaxin in 1993. It is currently manufactured through large-scale semi-synthetic methods starting with the fermentation product erythromycin. Semi-synthesis is a type of chemical synthesis that uses compounds isolated from abundant, natural sources as starting material.

About the API

Systematic name (3R,4S,5S,6R,7R,9R,11R,12R,13S,14R)-6-[(2S,3R,4S,6R)-4-(dimethylamino)-3-hydroxy-6-methyloxan-2-yl]oxy-14-ethyl-12,13-dihydroxy-4-[(2R,4R,5S,6S)-5-hydroxy-4-methoxy-4,6-dimethyloxan-2-yl]oxy-7-methoxy-3,5,7,9,11,13-hexamethyl-oxacyclotetradecane-2,10-dione
Trade name(s) Biaxin
Technology Synthetic Organic Chemistry
Molecular Formula C38H69NO13 Molecular Weight
Physical properties white to off-white crystalline powder
Therapeutic category Infectious disease
Available formulations Injectables Oral Liquid Oral Solid Oral Solid Long-Acting
Regulations CEP Flag CEP EU DMF Flag EU DMF US DMF Flag US DMF