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C4H7N3O 113.12
Creatinine contains NLT 98.5% and NMT 102.0% of C4H7N3O, as Creatinine, calculated on the dried basis.
•  Procedure
Sample:  40 mg of Creatinine
Titrimetric system 
Mode:  Direct titration
Titrant:  0.1 N perchloric acid VS
Endpoint detection:  Potentiometric
Indicator electrode:  Glass
Reference electrode:  Silver–silver chloride
Reference electrode solution:  Saturated lithium perchlorate and silver chloride in glacial acetic acid
Analysis:  Dissolve the Sample in 10 mL of glacial acetic acid. Titrate the Sample with 0.1 N perchloric acid VS. Perform a blank determination, and make any necessary correction.
Calculate the percentage of creatinine (C4H7N3O) in the Sample taken:
Result = [(V B) × N × F × 100]/W
V== volume of the Titrant consumed by the Sample (mL)
B== volume of the Titrant consumed by the Blank (mL)
N== actual normality of the Titrant (mEq/mL)
F== equivalency factor, 113.12 mg/mEq
W== weight of the Sample (mg)
Acceptance criteria:  98.5%–102.0% on the dried basis
•  Residue on Ignition 281: NMT 0.2%
•  Loss on Drying 731: Dry a sample at 105 for 3 h: it loses NMT 3.0% of its weight.
•  Packaging and Storage: Preserve in well-closed containers.
•  USP Reference Standards 11
USP Creatinine RS Click to View Structure
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, M.S.
Scientific Liaison
(EXC2010) Monographs - Excipients
Reference Standards RS Technical Services
USP35–NF30 Page 1773