Fifteen-membered rings

thumb|Azithromycin pills in Europe, with brand name Sumamed. Azithromycin, sold under the brand names Zithromax (in oral form) and Azasite (as an eye drop), is an antibiotic medication used to treat several bacterial infections. These include middle ear infections, strep throat, pneumonia, traveler's diarrhea, sexually transmitted infection, and certain other intestinal infections. Along with other medications, it may also be used for malaria. It is administered by mouth, into a vein, or as topical treatment for the eye.

Cyclopentadecane is the organic compound with the formula . It is a fifteen-member ring hydrocarbon. The compound is a precursor to the fragrance and scent muscone by autoxidation to cyclopentadecanol.