Packaging and storage
Preserve in tight containers.
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.
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.