Name: Erythromycin USP

T.S.No.: SPEC/API/HEB-004/D/01
Issue Date: 01/03/2006

Code: HEB

CAS: 114-07-8

Storage: Preserve in tight containers.

Supersede: SPEC/API/HEB-004/D
Date: 01/04/2002

M.F.:  C37 H67 NO13

M.W.: 733.94g/mole







A white or slightly yellow, crystalline powder.It should odorless or practically odorless.



Slightly soluble in water; soluble in alcohol, in chloroform and in ether.

Identification (By IR)


The IR absorption spectrum of a solution should exhibit maxima only at the same wavelengths as that of a similarly prepared solution of working standard of Erythromycin, except in the region between 1980 cm-1 and 2050cm-1

Specific rotation


Between - 71.00° to - 78.00°.



Meets the requirement.

Water Content


Not more than 10.00%w/w.

Residue On Ignition


Not More Than 0.200%w/w.

Limits of Thiocyanate


Not More Than 0.30%w/w.

Limit of Related Substances
( By HPLC )


Erythromycin B should not be more than 12.00%w/w,
Erythromycin C should not be more than 5.00%w/w,
Erythromycin A enol ether should not be more than 3.00%w/w, and

Any other individual impurity should not be more than 3.00%w/w.

Residual solvents


Acetone: Not more than 5000.00ppm.

Methylene chloride: Not more than 600.00ppm.



The sum of the percentages of Erythromycin A, Erythromycin B and Erythromycin C should not be less than 85.00%w/w and not more than 100.50%, calculated on anhydrous basis.

End of specification