Erythromycin Pledgets, USP contains erythromycin ((3R*,4S*,5S*,6R*,7R*,9R*,11R*,12R*,13S*,14R*)-4-[(2,6-Dideoxy-3-C-methyl-3-O-methyl-α-⌊-ribo-hexopyranosyl)-oxy]-14-ethyl-7,12,13-trihydroxy 3,5,7,9,11,13-hexamethyl-6-[[3,4,6-trideoxy-3-(dimethylamino)-β-d-xylo-hexopyranosyl]oxy]oxacyclotetradecane-2,10-dione), for topical dermatologic use. Erythromycin is a macrolide antibiotic produced from a strain of Saccharopolyspora erythraea (formerly Streptomyces erythreus).
It is a base and readily forms salts with acids. Chemically, erythromycin is C37H67NO13. It has the following structural formula:
Erythromycin has the molecular weight of 733.94
It is a white powder, is freely soluble in alcohols, acetone, chloroform, acetonitrile, ethyl acetate, and moderately soluble in ether, ethylene dichloride and amyl acetate. Erythromycin pledgets, USP are absorbent pads impregnated with Erythromycin Topical Solution 2%. Each pledget contains 1 mL of Erythromycin Topical Solution 2% and each 1 mL of Erythromycin Topical Solution 2% contains 20 mg of erythromycin base in a vehicle consisting of alcohol (71.5% v/v) and propylene glycol. May contain anhydrous citric acid and/or alcohol to adjust pH.