Cytarabine

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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C₉H₁₃N₃O₅            243.22

2(1H)-Pyrimidinone, 4-amino-1-ẞ-D-arabinofuranosyl-;

1-B-D-Arabinofuranosylcytosine CAS RN^®: 147-94-4.

1 DEFINITION

Cytarabine contains NLT 98.0% and NMT 102.0% of cytarabine (CHNO), calculated on the dried basis.

Change to read:

2 IDENTIFICATION 

A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197A or 197M _{▲(CN 1-May-2020)}

B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

3.1 PROCEDURE

Solution A: 0.73 g/L of monobasic sodium phosphate and 1.4 g/L of dibasic sodium phosphate in water

Mobile phase: Methanol and Solution A (5:95)

Standard solution: 0.1 mg/mL of USP Cytarabine RS in water

System suitability solution: 0.1 mg/mL each of USP Uracil Arabinoside RS and USP Cytarabine RS in water, prepared as follows. Dissolve USP Uracil Arabinoside RS in Standard solution.

Sample solution: 0.1 mg/mL of Cytarabine in water

3.1.1 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm x 25-cm; packing 11

Flow rate: 1.0 mL/min.

Injection volume: 10 µL

[NOTE-After chromatography has been completed, flush the column with a mixture of water and methanol (7:3).]

3.1.2 System suitability

Samples: Standard solution and System suitability solution

[NOTE-The relative retention times for cytarabine and uracil arabinoside are about 1.0 and 1.3, respectively.]

3.1.3 Suitability requirements

Resolution: NLT 2.5 between cytarabine and uracil arabinoside, System suitability solution

Relative standard deviation: NMT 0.73%, Standard solution

3.1.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of cytarabine (C₉H₁₃N₃O₅ ) in the portion of Cytarabine taken: 

                Result = (r_U/r_S) x (C_S/C_U) × 100

r_U = peak response from the Sample solution 

r_S = peak response from the Standard solution

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

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

Acceptance criteria: 98.0%-102.0% on the dried basis

4 IMPURITIES

4.1 RESIDUE ON IGNITION (281): NMT 0.5%

4.2 ORGANIC IMPURITIES

Buffer A: 0.02 M monobasic sodium phosphate in water

Buffer B: 0.02 M dibasic sodium phosphate in water

Buffer: Buffer A and Buffer B (1:1). Adjust with 0.1 M sodium hydroxide or 0.1 M phosphoric acid to a pH of 7.0.

Solution A: Methanol and Buffer (2:98)

Solution B: Methanol and Buffer (30:70)

Mobile phase: See Table 1.

Table 1

System suitability solution: 0.02 mg/mL of USP Uridine RS, 0.02 mg/mL of USP Uracil Arabinoside RS, and 5.0 mg/mL of USP Cytarabine RS in water

Standard solution: 4 µg/mL of USP Cytarabine RS in water

Sample solution: 5 mg/mL of Cytarabine in water. Prepare this solution fresh daily.

4.2.1 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm x 25-cm; packing 11

Flow rate: 1 mL/min

Injection volume: 20 µL

4.2.2 System suitability

Samples: System suitability solution and Standard solution

4.2.3 Suitability requirements

Resolution: NLT 1.25 between cytarabine and uridine, System suitability solution

Relative standard deviation: NMT 3.0%, Standard solution

4.2.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity in the portion of Cytarabine taken:

                Result = (r_U/r_S) x (C_S/C_U) × (1/F) × 100

r_U = peak response of each impurity from the Sample solution

r_S = peak response of cytarabine from the Standard solution

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

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

F = relative response factor for each individual impurity (see Table 2)

Acceptance criteria: See Table 2.

Table 2  

^a (2R,3R,3aS,9aR)-2-(Hydroxymethyl)-6-imino-2,3,3a, 9a-tetrahydro-6H-furo [2',3':4,5]oxazolo[3,2-a]pyrimidin-3-ol.

^b 6-Amino-2(1H)-pyramidinone.

^c Pyrimidine-2,4(1H,3H)-dione.

^d 1-B-D-Ribofuranosylpyrimidine-2,4(1H,3H)-dione.

5 SPECIFIC TESTS

OPTICAL ROTATION (781S), Procedures. Specific Rotation

Sample solution: 10 mg/mL in water

Acceptance criteria: +154° to +160"

LOSS ON DRYING (731)

Analysis: Dry under vacuum at a pressure not exceeding 5 mm of mercury at 60 for 3 h.

Acceptance criteria: NMT 1.0%

STERILITY TESTS (71): Where the label states that Cytarabine is sterile, it meets the requirements.

BACTERIAL ENDOTOXINS TEST (85): Where the label states that Cytarabine is sterile or must be subjected to further processing during the preparation of injectable dosage forms, it contains NMT 0.07 USP Endotoxin Units/mg of cytarabine.

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in well-closed, light-resistant containers.

LABELING: Where it is intended for use in preparing injectable dosage forms, the label states that it is sterile or must be subjected to further processing during the preparation of injectable dosage forms.

USP REFERENCE STANDARDS (11)

USP Cytarabine RS

USP Uracil Arabinoside RS

2,4(1H,3H)-Pyrimidinedione, 1-ẞ-o-arabinofuranosyl-.

C₉H₁₂N₂O₆          244.20

USP Uridine RS

1-B-0-Ribofuranosylpyrimidine-2,4(1H,3H)-dione.

C₉H₁₂N₂O₆          244.20