» Erythromycin Tablets contain not less than 90.0 percent and not more than 120.0 percent of the labeled amount of C37H67NO13.
[noteTablets that are enteric-coated meet the requirements for Erythromycin Delayed-Release Tablets. ]
Packaging and storage Preserve in tight containers.
USP Reference standards 11
Identification Prepare a test solution by mixing a quantity of finely powdered Tablets 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.
Medium: 0.05 M pH 6.8 phosphate buffer (see Buffer solutions in the section Reagents, Indicators, and Solutions); 900 mL.
Apparatus 2: 50 rpm.
Time: 60 minutes.
Test solution If necessary, dilute a filtered portion of the solution under test with Medium to obtain a solution having a concentration of about 0.28 mg of erythromycin per mL, and mix.
Standard solution Dissolve an accurately weighed quantity of USP Erythromycin RS in methanol (not more than 1 mL of methanol for each 14 mg of the Reference Standard), and dilute with water, quantitatively and with mixing, to obtain a stock solution containing about 0.56 mg per mL. Immediately prior to use, dilute the stock solution quantitatively with water to obtain a Standard solution having a known concentration of about 0.28 mg per mL.
Procedure Transfer 5.0-mL portions of the Test solution and the Standard solution to separate 25-mL volumetric flasks, and treat each as follows: Add 2.0 mL of water, and allow to stand for 5 minutes with intermittent swirling. Add 15.0 mL of 0.25 N sodium hydroxide, dilute with Medium to volume, and mix. Heat to 60 for 5 minutes, and allow to cool. Concomitantly determine the absorbances of these solutions at the wavelength of maximum absorbance at about 236 nm, with a suitable spectrophotometer, using blank solutions similarly prepared, except that 2.0 mL of 0.5 N sulfuric acid is substituted for the 2.0 mL of water. Calculate the amount of C37H67NO13 dissolved.
Tolerances Not less than 70% (Q) of the labeled amount of C37H67NO13 is dissolved in 60 minutes.
Uniformity of dosage units 905: meet the requirements.
Loss on drying 731 Dry about 100 mg of powdered Tablets in a capillary-stoppered bottle in vacuum at 60 for 3 hours: it loses not more than 5.0% of its weight.
Assay Place not less than 4 Tablets in a high-speed glass blender jar with 200 mL of methanol, and blend for 3 minutes. Add 300 mL of Buffer No. 3, and blend for 3 minutes. Proceed as directed under AntibioticsMicrobial Assays 81, using an accurately measured volume of this stock test 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.
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USP35NF30 Page 3082