Generic and additional names: Clarithromycin

CAS name: 6-O-Methylerythromycin

CAS registry #: 81103-11-9

Molecular formula: C₃₈H₆₉NO₁₃

Molecular weight: 747.95

Intellectual property rights: Generic

Brand names: Biaxin (Abbott); Clathromycin (Taisho); Cyllind (Abbott); Klacid (Abbott); Klaricid (Abbott); Macladin (Guidotti); Naxy (Sanofi Winthrop); Veclam (Zambon); Zeclar (Abbott)

Solubility: Clarithromycin is soluble in acetone, slightly soluble in methanol, ethanol, and acetonitrile, and practically insoluble in water [FDA label]. Water solubility 0.33 mg/l [DrugBank].

Polarity: Log P 2.69 [DrugBank]. Other authors have obtained values of Log P = 1.7 at pH 7.4.¹

Acidity/basicity: pKa 8.99 [DrugBank]

Melting point: 217–220ºC [DrugBank]

Formulation and optimal human dosage: Biaxin is available as immediate-release tablets, extended-release tablets, and granules for oral suspension.

Each Biaxin tablet contains 250 mg or 500 mg of clarithromycin.

After constitution, each 5 ml of Biaxin suspension contains 125 mg or 250 mg of clarithromycin. Dose 250–1000 mg daily, higher amounts given in multiple doses [FDA label].