Erythromycin Topical Solution
» Erythromycin Topical Solution is a solution of Erythromycin in a suitable vehicle. It contains not less than 90.0 percent and not more than 125.0 percent of the labeled amount of C37H67NO13.
Packaging and storage— Preserve in tight containers.
Identification— Prepare a test solution by mixing a portion of the Topical Solution with methanol to obtain a concentration of about 2.5 mg of erythromycin per mL. Proceed as directed in the Identification test under Erythromycin Delayed-Release Capsules, beginning with “Prepare a Standard solution of USP Erythromycin RS.”
Water, Method I 921: not more than 8.0% if it contains 20 mg per mL, or not more than 5.0% if it contains 15 mg per mL, or not more than 2.0% if it contains acetone, 20 mL of a mixture of pyridine and methanol (1:1) being used in place of methanol in the titration vessel.
Alcohol content, Method II 611: between 92.5% and 107.5% of the labeled amount of C2H5OH.
Assay— Proceed as directed under Antibiotics—Microbial Assays 81, using an accurately measured volume of Topical Solution diluted quantitatively with Buffer No. 3 to yield a Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Ahalya Wise, M.S.
(MDANT05) Monograph Development-Antibiotics
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 2286