Sitagliptin Phosphate

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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1 DEFINITION

Sitagliptin Phosphate contains NLT 98.0% and NMT 102.0% of sitagliptin phosphate (C₁₆H₁₅F₆N₅O · H₃PO₄), calculated on the anhydrous and solvent-free basis.

2 IDENTIFICATION

A. SPECTROSCOPIC IDENTIFICATION TESTS 〈197〉 , Infrared Spectroscopy: 197A, 197K, or 197M

[NOTE—If the spectra obtained in the solid state show differences, dissolve the substance to be examined and the reference substance separately in dehydrated alcohol, evaporate to dryness, and record new spectra using the residues.]

B. Meets the requirements of the test for Enantiomeric Purity

C. IDENTIFICATION TESTS—GENERAL 〈191〉 , Phosphate: A solution containing about 40 mg/mL in water meets the requirements of test A of Orthophosphates.

3 ASSAY

PROCEDURE

Buffer: 1.36 g/L of monobasic potassium phosphate, adjusted with phosphoric acid to a pH of 2.0 Mobile phase: Acetonitrile and Buffer (15:85)

Dilute phosphoric acid: Transfer 1 mL of phosphoric acid to a 1-L volumetric flask, and dilute with water to volume.

Diluent: Acetonitrile and Dilute phosphoric acid (5:95)

Standard solution: 0.1 mg/mL of USP Sitagliptin Phosphate RS in Diluent Sample solution: 0.1 mg/mL of Sitagliptin Phosphate in Diluent Chromatographic system

(See Chromatography 〈621〉, System Suitability.) Mode: LC

Detector: UV 205 nm

Column: 4.6-mm × 15-cm; 5-µm packing L10 Column temperature: 30°

Flow rate: 1.0 mL/min Injection volume: 20 µL

System suitability

Sample: Standard solution

Suitability requirements

Relative standard deviation: NMT 0.73% Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of sitagliptin phosphate (C₁₆H₁₅F₆N₅O · H₃PO₄) in the portion of Sitagliptin Phosphate taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak area from the Sample solution

r_S = peak area from the Standard solution

C_S = concentration of USP Sitagliptin Phosphate RS in the Standard solution (mg/mL)

C_U = concentration of Sitagliptin Phosphate in the Sample solution (mg/mL)

Acceptance criteria: 98.0%–102.0% on the anhydrous and solvent-free basis

4 IMPURITIES

Change to read:

4.1 ORGANIC IMPURITIES

Buffer, Mobile phase, Dilute phosphoric acid, Diluent, Sample solution, and Chromatographic system: Proceed as directed in the Assay.

System suitability solution: Place 10 mg of Sitagliptin Phosphate and 1 mg of sodium stearyl fumarate into a vial, add 1 mL of water, and tightly seal the vial. Heat at 80° for about 30 h to generate a fumarate adduct of sitagliptin. [NOTE—The chemical name of fumarate adduct of sitagliptin is 2-[[(R)-4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2- yl]amino]succinic acid.] Transfer the content of the vial into a 100-mL volumetric flask using a small amount of Diluent, and dilute with Diluent to volume. Mix well by stirring for 1 h. Centrifuge a portion of the solution for 10 min or until the solution is clear, and use the supernatant.

Standard solution: 0.0001 mg/mL of USP Sitagliptin Phosphate RS in Diluent

System suitability

Sample: System suitability solution

[NOTE—The relative retention times for sitagliptin and fumarate adduct of sitagliptin are 1.0 and 1.2, respectively.] Suitability requirements

Resolution: NLT 1.5 between sitagliptin and fumarate adduct of sitagliptin Analysis

Samples: Sample solution and Standard solution

Calculate the percentage of each impurity in the portion of Sitagliptin Phosphate taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of each impurity from the Sample solution

r_S = peak response of sitagliptin from the Standard solution

C_S = concentration of USP Sitagliptin Phosphate RS (ERR 1-Jul-2023) in the Standard solution (mg/mL)

C_U = concentration of Sitagliptin Phosphate in the Sample solution (mg/mL)

Acceptance criteria: Disregard any peak below 0.05%.

Any individual impurity: NMT 0.10%

Total impurities: NMT 0.5%

4.2 ENANTIOMERIC PURITY

Mobile phase: Dehydrated alcohol, chromatographic n-heptane, diethylamine, and water (600:400:1:1) Diluent: Methanol and water (9:1)

System suitability solution: 8 mg/mL of USP Sitagliptin System Suitability Mixture RS in Diluent Sample solution: 8 mg/mL of Sitagliptin Phosphate in Diluent

Sensitivity solution: 8 µg/mL of Sitagliptin Phosphate in Diluent from the Sample solution

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 268 nm

Column: 4.6-mm × 25-cm; 5-µm packing L51

Column temperature: 35°

Flow rate: 0.8 mL/min Injection volume: 10 µL

System suitability

Samples: System suitability solution and Sensitivity solution

[NOTE—The relative retention times for sitagliptin, which is the R-enantiomer, and the S-enantiomer are 1.0 and 0.9, respectively.]

Suitability requirements

Resolution: NLT 1.5 between the S-enantiomer and sitagliptin, System suitability solution Signal-to-noise ratio: NLT 10 for the sitagliptin peak, Sensitivity solution

Analysis

Sample: Sample solution

Calculate the percentage of S-enantiomer in the portion of Sitagliptin Phosphate taken:

Result = (r_U/r_T) × 100

r_U = peak response of the S-enantiomer from the Sample solution

r_T = sum of the peak responses of the S-enantiomer and sitagliptin from the Sample solution

Acceptance criteria: NMT 0.5% of the S-enantiomer

5 SPECIFIC TESTS

WATER DETERMINATION, Method Ia 〈921〉: 3.3%–3.7%

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in well-closed containers. Store at room temperature.

USP REFERENCE STANDARDS 〈11〉

USP Sitagliptin Phosphate RS

USP Sitagliptin System Suitability Mixture RS

Sitagliptin Phosphate containing S-enantiomer.