Identification
Prepare a test solution containing the equivalent of 4mg of amoxicillin per mLby adding 0.1Nhydrochloric acid to powder from Amoxicillin Capsules.Prepare a Standard solution of
USP Amoxicillin RSin 0.1Nhydrochloric acid containing 4mg per mL.Use within 10minutes after preparation.Apply separately 5µLof each solution on a thin-layer chromatographic plate coated with a 0.25-mm layer of chromatographic silica gel mixture (see
Chromatography á621ñ).Place the plate in a suitable chromatographic chamber,and develop the chromatogram in a solvent system consisting of a mixture of methanol,chloroform,water,and pyridine (90:80:30:10).When the solvent front has moved about three-fourths of the length of the plate,remove the plate from the chamber,and dry with warm air for 10minutes.Locate the spots on the plate by spraying lightly with a solution of ninhydrin in alcohol containing 3mg per mL,and dry at 110

for 15minutes:the
RFvalue of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.
Dissolution á711ñ
Medium:
water;900mL.
Apparatus 1:
100rpm.
Time:
60minutes.
Procedure
Determine the amount of C
16H
19N
3O
5Sdissolved by employing UVabsorption at the wavelength of maximum absorbance at about 272nm on filtered portions of the solution under test,suitably diluted with water,if necessary,in comparison with a Standard solution having a known concentration of
USP Amoxicillin RSin the same
Medium.
Tolerances
Not less than 80%(Q)of the labeled amount of C16H19N3O5Sis dissolved in 60minutes.
Assay
Diluent,Mobile phase,Standard preparation,and Chromatographic system
Prepare as directed in the
Assayunder
Amoxicillin.
Assay preparation
Remove,as completely as possible,the contents of not fewer than 20Capsules,and weigh accurately.Mix the combined contents,and transfer an accurately weighed quantity,equivalent to about 200mg of anhydrous amoxicillin,to a 200-mLvolumetric flask,add Diluentto volume,and mix.Sonicate if necessary to ensure complete dissolution.Pass a portion of this solution through a suitable filter of 1-µm or finer porosity,and use the filtrate as the Assay preparation.Use this solution within 6hours.
Procedure
Proceed as directed for
Procedurein the
Assayunder
Amoxicillin.Calculate the quantity,in mg,of amoxicillin (C
16H
19N
3O
5S)in the portion of Capsules taken by the formula:
0.2CP(rU/rS),
in which the terms are as defined therein.