Cefadroxil for Oral Suspension
DEFINITION
Cefadroxil for Oral Suspension is a dry mixture of Cefadroxil and one or more suitable buffers, colors, diluents, and flavors. It contains the equivalent of NLT 90.0% and NMT 120.0% of the labeled amount of C16H17N3O5S.
IDENTIFICATION
• Thin-Layer Chromatography
Standard solution:
2 mg/mL of USP Cefadroxil RS
Sample solution:
Constitute 1 container of Cefadroxil for Oral Suspension as directed in the labeling. Dilute a portion of the resulting suspension with water to a concentration of 2 mg/mL. Pass through a suitable filter.
Chromatographic system
Mode:
TLC
Adsorbent:
0.25-mm layer of binder-free silica gel
Application volume:
20 µL
Pre-developing solvent system:
n-Hexane and tetradecane (95:5)
Solution A:
1 in 15 solution of ninhydrin in acetone
Developing solvent system:
0.1 M citric acid, 0.1 M dibasic sodium phosphate, and Solution A (60:40:15)
Spray reagent:
1 in 500 solution of ninhydrin in dehydrated alcohol. Protect this solution from light.
Analysis
Samples:
Standard solution and Sample solution
Place the thin-layer chromatographic plate in a chamber containing the Pre-developing solvent system and allow the solvent front to move the length of the plate. Remove the plate from the chamber and allow the solvent to evaporate. Apply the Sample solution and Standard solution to the plate, allow the spots to dry, and develop the chromatogram in the Developing solvent system until the solvent front has moved three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow to air-dry. Spray the plate with the Spray reagent, dry for 10 min at 110
, and examine the chromatogram.
, and examine the chromatogram.
Acceptance criteria:
The RF value of the principal spot of the Sample solution corresponds to that of the Standard solution.
ASSAY
• Procedure
Buffer:
6.86 g/L of monobasic potassium phosphate. Adjust with 10 N potassium hydroxide to a pH of 5.0.
Mobile phase:
Acetonitrile and Buffer (40:960)
Standard solution:
1.06 mg/mL of USP Cefadroxil RS in Buffer. Use this solution on the day prepared. [Note—This solution contains the equivalent of 1 mg/mL of cefadroxil (C16H17N3O5S). ]
Sample solution:
Constitute a container of Cefadroxil for Oral Suspension as directed in the labeling. Dilute a portion of the resulting suspension with Buffer to prepare a solution containing nominally 1 mg/mL. Pass through a suitable filter of 0.8-µm or finer pore size, and use the filtrate. Use this solution on the day prepared.
Chromatographic system
Mode:
LC
Detector:
UV 230 nm
Column:
4-mm × 25-cm; packing L1
Flow rate:
1.5 mL/min
Injection size:
10 µL
System suitability
Sample:
Standard solution
Suitability requirements
Capacity factor, k ¢:
2.0–3.5
Column efficiency:
NLT 1800 theoretical plates
Tailing factor:
NMT 2.2
Relative standard deviation:
NMT 2.0%
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of the labeled amount of cefadroxil (C16H17N3O5S) in the portion of Cefadroxil for Oral Suspension taken:
Result = (rU/rS) × (CS/CU) × P × F × 100
| rU | = | = peak response of cefadroxil from the Sample solution |
| rS | = | = peak response of cefadroxil from the Standard solution |
| CS | = | = concentration of USP Cefadroxil RS in the Standard solution (mg/mL) |
| CU | = | = nominal concentration of cefadroxil in the Sample solution (mg/mL) |
| P | = | = potency of cefadroxil in USP Cefadroxil RS (µg/mg) |
| F | = | = conversion factor, 0.001 mg/µg |
Acceptance criteria:
90.0%–120.0%
PERFORMANCE TESTS
• Dissolution 
711
711
Medium:
Water; 900 mL
Apparatus 2:
25 rpm
Time:
30 min
Standard solution:
USP Cefadroxil RS in Medium at a known concentration
Sample solution:
Transfer 5.0 mL of the constituted Cefadroxil for Oral Suspension (weighed) to the dissolution vessel.
Analysis:
Determine the amount of cefadroxil dissolved by employing UV absorption at the wavelength of 263 nm on the Sample solution in comparison with the Standard solution.
Calculate the amount of cefadroxil dissolved:
Result = (AU/AS) × (CS/D) × V
| AU | = | = absorbance of the Sample solution |
| AS | = | = absorbance of the Standard solution |
| CS | = | = concentration of the Standard solution (mg/mL) |
| V | = | = volume of Medium, 900 mL |
| D | = | = dilution factor |
Tolerances:
NLT 75% (Q) of the labeled amount of cefadroxil is dissolved.
• Uniformity of Dosage Units 905
905
For solid packaged in single-unit containers:
Meets the requirements
• Deliverable Volume 698:
Meets the requirements
698:
Meets the requirements
SPECIFIC TESTS
• pH 791:
4.5–6.0, in the suspension constituted as directed in the labeling
791:
4.5–6.0, in the suspension constituted as directed in the labeling
• Water Determination, Method I 921:
NMT 2.0%, except where it is labeled as containing 100 mg of cefadroxil per mL after constitution, in which case the limit is NMT 3.0%
921:
NMT 2.0%, except where it is labeled as containing 100 mg of cefadroxil per mL after constitution, in which case the limit is NMT 3.0%
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in tight containers.
• USP Reference Standards 11
11
USP Cefadroxil RS 
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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 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 2530
Pharmacopeial Forum: Volume No. 36(2) Page 385