Erygel (Erythromycin Topical Gel) - Description and Clinical Pharmacology

RX Only

For Dermatologic Use Only - Not for Ophthalmic Use

DESCRIPTION:

ERYGEL^® Topical Gel contains erythromycin ((3R*, 4S*, 5S*, 6R*, 7R*, 9R*, 11R*, 12R*, 13S*, 14R*)-4-[(2, 6-Dideoxy-3- C -methyl-3- O -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)-Β-D- xylo -hexopyranosyl]oxy] oxacyclotetradecane-2, 10-dione), for topical dermatological 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 C}37^H67^NO13^{. It has the following structural formula:}

Erythromycin has a molecular weight of 733.94. It is a white or slightly yellow, odorless or practically odorless, bitter crystalline powder. Erythromycin is very soluble in very polar organic solvents such as alcohols, acetone, chloroform, acetonitrile and ethyl acetate. It is moderately soluble in less polar solvents such as ether, dichloroethylene and amyl acetate. It is slightly soluble in nonpolar solvents such as hexane. It is very poorly soluble in water.

Each gram of ERYGEL^® Topical Gel contains 20 mg of erythromycin, USP in a base of alcohol 92% and hydroxypropyl cellulose.

CLINICAL PHARMACOLOGY:

The exact mechanism by which erythromycin reduces lesions of acne vulgaris is not fully known; however, the effect appears to be due in part to the antibacterial activity of the drug.

MICROBIOLOGY:

Erythromycin acts by inhibition of protein synthesis in susceptible organisms by reversibly binding to 50S ribosomal subunits, thereby inhibiting translocation of aminoacyl transfer-RNA and inhibiting polypeptide synthesis. Antagonism has been demonstrated in vitro between erythromycin, lincomycin, chloramphenicol, and clindamycin.