Erythromycin topical solution, USP 2% contains erythromycin, USP for topical dermatologic use. Erythromycin is a macrolide antibiotic produced from a strain of
Saccaropolyspora erythraea (formerly
Streptomyces erythreus). It is a base and readily forms salts with acids. Chemically, erythromycin is: (3
R*,4
S*,5
S*,6
R*,7
R*,9
R*,11
R*,12
R*,13
S*,14
R*)-4-[(2,6-Dideoxy-3-
C-methyl-3-
0-methyl-α-L-
ribo-hexopyranosyl)oxy]-14-ethyl-7,12,13-trihydroxy -3,5,7,9,11,13-hexamethyl-6-[[3,4,6-trideoxy-3-(dimethylamino)-ß-D-
xylo-hexopyranosyl]oxy]oxacyclotetradecane-2,10-dione. It has the following structural formula:
Structural Formula (Image 01)
Molecular Formula: C
37H
67NO
13
Molecular Weight: 733.94
Erythromycin, USP is a white or slightly yellow, crystalline powder that is soluble in water, alcohol, chloroform and in ether.
Each mL of erythromycin topical solution, USP 2% contains 20 mg of erythromycin base in a vehicle consisting of alcohol (66%), citric acid, and propylene glycol.