Erythromycin Stearate Tablets
»Erythromycin Stearate Tablets contain the equivalent of not less than 90.0percent and not more than 120.0percent of the labeled amount of erythromycin (C37H67NO13).
Packaging and storage— Preserve in tight containers.
Identification— To a quantity of powdered Tablets add a volume of methanol sufficient to yield a solution containing the equivalent of about 5mg of erythromycin per mL.Shake this mixture by mechanical means for about 30minutes.Centrifuge a portion of this mixture,and use the clear supernatant as the test solution.Prepare a Standard solution of USP Erythromycin Stearate RSin methanol containing about 8mg per mL.Apply separately 20µLeach of the test solution and the Standard solution to a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture,and allow to dry.Place the plate in an unlined chromatographic chamber,and develop the chromatograms in a solvent system consisting of a mixture of methanol and chloroform (85:15)until the solvent front has moved about 9cm.Remove the plate from the chamber,mark the solvent front,and allow the solvent to evaporate.Spray the plate with a methanolic solution of 2¢,7¢-dichlorofluorescein (1in 500),and examine the plate under long-wavelength UVlight:the RFvalues of the principal fluorescent spots obtained from the test solution correspond to those obtained from the Standard solution.Then spray the plate with a mixture of dehydrated alcohol,p-methoxybenzaldehyde,and sulfuric acid (90:5:5).Heat the plate at 100for 10minutes,and examine the chromatograms,in which the erythromycin appears as a black-to-purple spot:the RFvalue of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.
Dissolution á711ñ—
Medium: 0.05MpH6.8phosphate buffer (see under Solutionsin the section Reagents,Indicators,and Solutions);900mL.
Apparatus 2: 100rpm.
Time: 120minutes.
Stock standard solution— Dissolve an accurately weighed quantity of USP Erythromycin RSin methanol to obtain a solution containing about 14mg per mL.Dilute quantitatively with water,and mix to obtain a solution having a known concentration of about 0.56mg of USP Erythromycin RSper mL.
Working standard solution— On the day of use,dilute 25.0mLof Stock standard solutionwith water to 50.0mL,and mix.
Test solution— After 120minutes,withdraw a portion of the solution under test,filter,and dilute with Medium,if necessary,to obtain a solution having an estimated concentration of about 0.28mg of erythromycin per mL.
Procedure— Transfer 5.0-mLportions of the Working standard solutionto two 25-mLvolumetric flasks,one of which serves as a working standard blank.Similarly,transfer 5.0-mLportions of the Test solutionto two 25-mLvolumetric flasks,one of which serves as a blank for that Test solution.To each of the flasks designated as a blank add 2.0mLof 0.5Nsulfuric acid and to the remaining flasks add 2.0mLof water.Allow to stand for 5minutes with intermittent swirling.To all flasks add 15.0mLof 0.25Nsodium hydroxide,dilute with Mediumto volume,and mix.Heat the flasks in a water bath at 60±0.5for 5minutes,and allow to cool.Using a suitable spectrophotometer,determine the absorbance of each solution,corrected for its blank solution,at the wavelength of maximum absorbance at about 236nm.Determine the amount of C37H67NO13dissolved from the Test solutionin comparison with the solution obtained from the Working standard solution.
Tolerances— Not less than 75%(Q)of the labeled amount of C37H67NO13is dissolved in 120minutes.
Uniformity of dosage units á905ñ: meet the requirements.
Loss on drying á731ñ— Dry about 100mg of powdered Tablets in a capillary-stoppered bottle in vacuum at 60for 3hours:it loses not more than 5.0%of its weight.
Assay— Proceed with Tablets as directed in the Assayunder Erythromycin Tablets.
Auxiliary Information— Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 771
Phone Number:1-301-816-8335