Azathioprine Oral Suspension
Azathioprine Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of azathioprine (C9H7N7O2S).
Prepare Azathioprine Oral Suspension of 50 mg/mL as follows (see Pharmaceutical CompoundingNonsterile Preparations 795).
If using tablets, comminute them to a fine powder in a suitable mortar, or add Azathioprine powder to the mortar. Add about 10 mL of the Vehicle, and mix to a uniform paste. Add the Vehicle in small portions almost to volume, and mix thoroughly after each addition. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add sufficient Vehicle to bring to final volume, and mix well.
[CautionAvoid skin contact or inhalation of azathioprine by using protective gloves and a fume hood or surgical mask. ]
Mobile phase: Dissolve 1.1 g of sodium-1-heptanesulfonate in 700 mL of water, and add 300 mL of methanol. Adjust with 1 N hydrochloric acid to a pH of 3.5.
Standard solution: 25 mg of USP Azathioprine RS, in a 50-mL volumetric flask. Add 15 mL of methanol and 0.5 mL of ammonium hydroxide to the flask, swirl, and sonicate for 2 min. Dilute with methanol to volume. Transfer 10 mL of this solution to a 50-mL volumetric flask, and dilute with water to volume.
Sample solution: Agitate the container of Oral Suspension for 30 min on a rotating mixer, remove a 5-mL sample, and store in a clear glass vial at 70 until analyzed. At the time of analysis, remove the sample from the freezer, allow it to reach room temperature, and mix with a vortex mixer for 30 s. Pipet 1.0 mL of the Sample into a 100-mL volumetric flask, and dilute with Mobile phase to volume.
Detector: UV 254 nm
Column: 4.6-mm × 25-cm; 5-µm packing L1
Flow rate: 2 mL/min
Injection size: 20 µL
Sample: Standard solution
[NoteThe retention time for the azathioprine peak is about 4 min. ]
Relative standard deviation: NMT 1.3% for replicate injections
Samples: Standard solution and Sample solution
Calculate the percentage of the labeled amount of azathioprine (C9H7N7O2S) in the portion of Oral Suspension taken:
Result = (rU/rS) × (CS/CU) × 100
Acceptance criteria: 90.0%110.0%
• pH 791: 3.84.8
• Packaging and Storage: Package in tight, light-resistant containers. Store at room temperature, or in a cold place.
• Labeling: Label it to state that it is to be well shaken before use, and to state the Beyond-Use Date.
• Beyond-Use Date: NMT 60 days after the day on which it was compounded
• USP Reference Standards 11
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USP35NF30 Page 2277Pharmacopeial Forum: Volume No. 32(1) Page 48