Amoxicillin Capsules
DEFINITION
Amoxicillin Capsules contain the equivalent of NLT 90.0% and NMT 120.0% of the labeled amount of amoxicillin (C16H19N3O5S).
IDENTIFICATION
•  The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
ASSAY
•  Procedure
Buffer:  Dissolve 6.8 g/L of monobasic potassium phosphate in water. Adjust with a 45% (w/w) solution of potassium hydroxide to a pH of 5.0 ± 0.1.
Mobile phase:  Acetonitrile and Buffer (1:24)
Standard solution:  1.2 mg/mL of USP Amoxicillin RS in Buffer. [Note—Use this solution within 6 h. ]
Sample solution:  Remove, as completely as possible, the contents of NLT 20 Capsules. Mix the combined contents, and transfer a quantity, equivalent to 200 mg of anhydrous amoxicillin, to a 200-mL volumetric flask. Add Buffer to volume. Sonicate if necessary to ensure complete dissolution. [Note—Use this solution within 6 h. ]
Chromatographic system 
Mode:  LC
Detector:  UV 230 nm
Column:  4-mm × 25-cm;10-µm packing L1
Flow rate:  1.5 mL/min
Injection size:  10 µL
System suitability 
Sample:  Standard solution
Suitability requirements 
Tailing factor:  NMT 2.5
Relative standard deviation:  NMT 2.0%
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of C16H19N3O5S in the portion of Capsules taken:
Result = (rU/rS) × (CS/CU) × P × F × 100
rU== peak response from the Sample solution
rS== peak response from the Standard solution
CS== concentration of USP Amoxicillin RS in the Standard solution (mg/mL)
CU== nominal concentration of amoxicillin in the Sample solution (mg/mL)
P== potency of amoxicillin in USP Amoxicillin RS (µg/mg)
F== conversion factor, 0.001 mg/µg
Acceptance criteria:  90.0%–120.0%
PERFORMANCE TESTS
•  Dissolution 711
Test 1 
Medium:  Water; 900 mL
Apparatus 1:  100 rpm, for Capsules containing 250 mg
Apparatus 2:  75 rpm, for Capsules containing 500 mg
Time:  60 min
Analytical wavelength:  UV 272 nm
Standard solution:  USP Amoxicillin RS in Medium
Sample solution:  Pass a portion of the solution under test through a suitable filter. Dilute with Medium, if necessary, to a concentration that is similar to that of the Standard solution.
Tolerances:  NLT 80% (Q) of the labeled amount of C16H19N3O5S is dissolved.
Test 2:  If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 2.
Medium:  Water; 900 mL
Apparatus 1:  100 rpm
Time:  90 min
Analytical wavelength:  UV 272 nm
Standard solution:  USP Amoxicillin RS in Medium
Sample solution:  Pass a portion of the solution under test through a suitable filter. Dilute with Medium, if necessary, to a concentration that is similar to that of the Standard solution.
Tolerances:  NLT 80% (Q) of the labeled amount of C16H19N3O5S is dissolved.
•  Uniformity of Dosage Units 905: Meet the requirements
SPECIFIC TESTS
•  Microbial Enumeration Tests 61 and Tests for Specified Microorganisms 62: The total aerobic microbial count does not exceed 103 cfu/g, and the total combined molds and yeasts count does not exceed 1022 cfu/g.
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.
•  Labeling: When more than one Dissolution test is given, the labeling states the Dissolution test used only if Test 1 is not used.
•  USP Reference Standards 11
USP Amoxicillin RS
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Ahalya Wise, M.S.
Senior Scientific Liaison
1-301-816-8161
(SM12010) Monographs - Small Molecules 1
711 Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison
1-301-816-8106
(GCDF2010) General Chapters - Dosage Forms
61 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
1-301-816-8339
(GCM2010) General Chapters - Microbiology
62 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
1-301-816-8339
(GCM2010) General Chapters - Microbiology
Reference Standards RS Technical Services
1-301-816-8129
rstech@usp.org
USP35–NF30 Page 2198
Pharmacopeial Forum: Volume No. 36(4) Page 892