Packaging and storage— Preserve in tight containers.

USP Reference standards 11— USP Erythromycin RS. USP Erythromycin Estolate RS.

Identification— Prepare a test solution by mixing a quantity of Erythromycin Estolate for Oral Suspension with methanol to obtain a concentration equivalent to about 20 mg of erythromycin per mL. Prepare a Standard solution of USP Erythromycin Estolate RS in methanol containing the equivalent of 20 mg of erythromycin per mL. Apply separately 3 µL of each solution to a thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel. Proceed as directed in the Identification test under Erythromycin Delayed-Release Capsules, beginning with “Place the plate in an unlined chromatographic chamber.”

Uniformity of dosage units 905—

Deliverable volume 698: meets the requirements.

pH 791: between 5.0 and 7.0 (if pediatric drops, between 5.0 and 5.5), in the suspension constituted as directed in the labeling.

Water, Method I 921: not more than 2.0%, 20 mL of methanol containing 10% of imidazole being used in place of methanol in the titration vessel.

Residual solvents 467: meets the requirements.

Assay— Constitute Erythromycin Estolate for Oral Suspension as directed in the labeling, and proceed as directed in the Assay under Erythromycin Estolate Oral Suspension.

Expert Committee : (MDANT05) Monograph Development-Antibiotics

USP29–NF24 Page 835

Phone Number : 1-301-816-8223