Calcium Acetate Tablets
DEFINITION
Calcium Acetate Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of calcium acetate (C4H6CaO4).
IDENTIFICATION
•  Identification Tests—General, Calcium 191 and Acetate 191
Sample solution:  100 mg/mL of calcium acetate from powdered Tablets
Acceptance criteria:  Meet the requirements
ASSAY
•  Procedure
Sample:  Amount equivalent to 300 mg of calcium acetate from NLT 20 powdered Tablets
Analysis:  Dissolve the Sample in 150 mL of water containing 2 mL of 3 N hydrochloric acid. While stirring, add 30 mL of 0.05 M edetate disodium VS from a 50-mL buret, and add 15 mL of 1 N sodium hydroxide and 300 mg of hydroxy naphthol blue. Continue the titration with the 0.05 M edetate disodium VS to a blue endpoint. Each mL of 0.05 M edetate disodium is equivalent to 7.909 mg of calcium acetate (C4H6CaO4).
Acceptance criteria:  90.0%–110.0%
PERFORMANCE TESTS
•  Dissolution 711
Medium:  Water; 900 mL
Apparatus 2:  50 rpm
Time:  30 min
Instrumental conditions 
Mode:  Atomic absorption spectrometry
Analytical wavelength:  422.8 nm
Standard solution:  Calcium at a known concentration 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 the Standard solution.
Acceptance criteria:  NLT 80% (Q) of the labeled amount of calcium acetate (C4H6CaO4) is dissolved.
•  Uniformity of Dosage Units 905: Meet the requirements
IMPURITIES
•  Limit of Aluminum
Buffer:  Dissolve 50 g of ammonium acetate in 150 mL of water, adjust with glacial acetic acid to a pH of 6.0, and dilute with water to 250 mL.
Aluminum standard solution  1.0 µg/mL of aluminum. Prepare as directed for Standard Preparation under Aluminum 206.
Standard solution:  Prepare a solution containing 2.0 mL of Aluminum standard solution, 5 mL of Buffer, and 48 mL of water, and extract this solution with successive portions of 10, 10, and 5 mL of 0.5% 8-hydroxyquinoline in chloroform. Combine the chloroform extracts in a 50-mL volumetric flask, and dilute the combined extracts with chloroform to volume.
Sample solution:  Dissolve a portion of powdered Tablets (NLT 10) equivalent to 1.0 g of calcium acetate in 50 mL of water, and add 5 mL of Buffer. Extract this solution with successive portions of 10, 10, and 5 mL of 0.5% 8-hydroxyquinoline in chloroform. Combine the chloroform extracts in a 50-mL volumetric flask, and dilute the combined extracts with chloroform to volume.
Blank:  Prepare a solution containing 50 mL of water and 5 mL of Buffer. Extract this solution with successive portions of 10, 10, and 5 mL of 0.5% 8-hydroxyquinoline in chloroform. Combine the chloroform extracts in a 50-mL volumetric flask, and dilute the combined extracts with chloroform to volume.
Instrumental conditions 
Mode:  Fluorescence
Excitation wavelength:  392 nm
Emission wavelength:  518 nm
Analysis 
Samples:  Standard solution, Sample solution, and Blank. Use the Blank solution to zero the instrument.
Acceptance criteria:  The fluorescence of the Sample solution does not exceed that of the Standard solution (NMT 2 ppm).
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in well-closed containers.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Domenick Vicchio, Ph.D.
Senior Scientific Liaison
1-301-998-6828
(SM42010) Monographs - Small Molecules 4
711 Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison
1-301-816-8106
(GCDF2010) General Chapters - Dosage Forms
USP35–NF30 Page 2440
Pharmacopeial Forum: Volume No. 27(6) Page 3254