Sodium Fluoride Tablets
DEFINITION
Sodium Fluoride Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of sodium fluoride (NaF).
IDENTIFICATION
• A. Identification Tests—General, Sodium 
191
191
Sample solution:
Disperse 20 finely powdered Tablets in 25 mL of water, shake, and filter. Use the filtrate.
Acceptance criteria:
The filtrate meets the requirements.
• B.
Sample solution:
Evaporate a 10-mL portion of the filtrate obtained in Identification test A to dryness.
Analysis:
To the residue add a mixture of 0.1 mL of freshly prepared 1 mg/mL sodium alizarinsulfonate solution and 0.1 mL of 1 mg/mL zirconyl nitrate in 7 N hydrochloric acid.
Acceptance criteria:
A yellow color is produced.
ASSAY
• Procedure
[Note—Store all solutions, except Buffer, in plastic containers. ]
Buffer:
Dissolve 57 mL of glacial acetic acid, 58 g of sodium chloride, and 4 g of (1,2-cyclohexylenedinitrilo)tetraacetic acid in 500 mL of water. Adjust with 5 N sodium hydroxide to a pH of 5.25 ± 0.25, and dilute with water to 1000 mL.
Standard solution A:
420 µg/mL of USP Sodium Fluoride RS, equivalent to 190 µg/mL of fluoride ion (10
2 M)
2 M)
Standard solution B:
19 µg/mL of fluoride ion (103 M), from Standard solution A
3 M), from Standard solution A
Standard solution C:
1.9 µg/mL of fluoride ion (104 M), from Standard solution B
4 M), from Standard solution B
Sample solution:
Finely powder NLT 20 Tablets. Transfer a portion of the powder equivalent to 10 mg of fluoride to a plastic 500-mL conical flask containing 400 mL of water. Heat on a steam bath for 25 min with occasional shaking, and cool to room temperature. Transfer to a 500-mL volumetric flask, and dilute with water to volume.
Analysis
Samples:
Standard solution A, Standard solution B, Standard solution C, and Sample solution
Pipet 20 mL of each Standard solution and of the Sample solution into separate plastic beakers each containing a plastic-coated stirring bar. Pipet 20 mL of Buffer into each beaker. Concomitantly measure the potentials (see pH 791), in mV, of the solutions from the Standard solutions and of the solution from the Sample solution, with a pH meter capable of a minimum reproducibility of ±0.2 mV and equipped with a fluoride-specific ion-indicating electrode and a suitable reference electrode.
791), in mV, of the solutions from the Standard solutions and of the solution from the Sample solution, with a pH meter capable of a minimum reproducibility of ±0.2 mV and equipped with a fluoride-specific ion-indicating electrode and a suitable reference electrode.
[Note—When taking measurements, immerse the electrodes in the solution, stir on a magnetic stirrer having an insulated top until equilibrium is attained (1–2 min), and record the potential. Rinse and dry the electrodes between measurements, taking care to avoid damaging the crystal of the specific-ion electrode. ]
Plot the logarithms of the fluoride-ion concentrations, inµg/mL, of the Standard solutions versus potential, in mV. From the measured potential of the Sample solution and the standard response line, determine the concentration, C, in µg/mL, of fluoride ion in the Sample solution.
Calculate the percentage of the labeled amount of fluoride ion in the portion of the Tablets taken:
Result = (C/CU) × 100
| C | = | = concentration of fluoride ion in the Sample solution (µg/mL) |
| CU | = | = nominal concentration of fluoride ion in the Sample solution (µg/mL) |
Calculate the percentage of the labeled amount of sodium fluoride in the portion of the Tablets taken:
Result = (C/CU) × (Mr/Ar) × 100
| C | = | = concentration of fluoride ion in the Sample solution (µg/mL) |
| CU | = | = nominal concentration of sodium fluoride in the Sample solution (µg/mL) |
| Mr | = | = molecular weight of sodium fluoride, 41.99 |
| Ar | = | = atomic weight of fluoride, 19.00 |
Acceptance criteria:
90.0%–110.0%
PERFORMANCE TESTS
• Disintegration 701:
NMT 15 min
701:
NMT 15 min
• Uniformity of Dosage Units 905:
Meet the requirements
905:
Meet the requirements
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in tight containers.
• Labeling:
Label the Tablets in terms of the content of sodium fluoride (NaF) and in terms of the content of fluoride ion. Tablets that are to be chewed may be labeled as Sodium Fluoride Chewable Tablets.
• USP Reference Standards 11
11
USP Sodium Fluoride RS
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Elena Gonikberg, Ph.D.
Principal Scientific Liaison 1-301-816-8251 |
(SM32010) Monographs - Small Molecules 3 |
| 701 |
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 4660