Stavudine

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

Stavudine contains NLT 98.0% and NMT 102.0% of stavudine (C₁₀H₁₂N₂O₄), calculated on an anhydrous and solvent-free basis.

2 IDENTIFICATION

Change to read:

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K (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

Procedure

All solutions containing stavudine must be prepared immediately before use and remain refrigerated until use.

Solution A: 0.77 g/L of ammonium acetate

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

Standard solution: 0.02 mg/mL of USP Stavudine RS in water

Sample solution: 0.02 mg/mL of Stavudine in water

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm × 3.3-cm; 3-μm packing L1

Flow rate: 0.7 mL/min

Injection volume: 25 μL

System suitability

Sample: Standard solution

[Note—The retention time of the stavudine peak is between 2.8 and 5.0 min.]

Suitability requirements

Column efficiency: NLT 800 theoretical plates

Tailing factor: NMT 1.6

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of stavudine in the portion of Stavudine taken:

Result = (r_U/r_S) × (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 Stavudine RS in the Standard solution (mg/mL)

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

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

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.3%

Organic Impurities

All solutions containing stavudine must be prepared immediately before use and remain refrigerated until use.

Solution A: 0.77 g/L of ammonium acetate in water

Solution B: Acetonitrile and Solution A (3.5:96.5)

Solution C: Acetonitrile and Solution A (25:75)

Mobile phase: See Table 1.

Table 1

System suitability solution: 0.50 mg/mL of USP Stavudine System Suitability Mixture RS in water

Sample solution: 0.5 mg/mL of Stavudine in water

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm × 25-cm; 5-μm packing L1

Flow rate: 2.1 mL/min

Injection volume: 10 μL

Run time: 2 times the retention time of the stavudine peak, or at least until the last impurity has eluted

System suitability

Sample: System suitability solution

[Note—The retention time of the main stavudine peak is 10.5 ± 2 min. The relative retention times for stavudine and thymine are listed in Table 2.]

Suitability requirements

Resolution: NLT 1.15 between the thymidine epimer and thymidine; NLT 1.0 between stavudine and α-stavudine

Column efficiency: NLT 9500 theoretical plates

Capacity factor, k′: NLT 4

Analysis

Samples: System suitability solution and Sample solution

Calculate the percentage of thymine in the portion of Stavudine taken:

Result = (r_U/r_T) × F × 100

r_U = peak response of thymine from the Sample solution

r_T = sum of all the peak responses from the Sample solution

F = relative response factor (see Table 2)

Calculate the percentage of all other impurities in the portion of Stavudine taken:

Result = (r_U/r_T) × 100

r_U = peak response for each impurity from the Sample solution

r_T = sum of all the peak responses from the Sample solution

Acceptance criteria: See Table 2. Disregard threshold is 0.03%.

Table 2

^a Including thymine.

5 SPECIFIC TESTS

Optical Rotation, Specific Rotation〈781S〉

Sample solution: 10 mg/mL

Acceptance criteria: −40° to −45°, calculated on the anhydrous basis

Water Determination, Method I〈921〉: NMT 0.5%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers, protected from light and humidity. Store at 25°, excursions permitted between 15° and 30°.

USP Reference Standards 〈11〉

USP Stavudine RS

USP Stavudine System Suitability Mixture RS

It is a mixture of stavudine and the following related compounds: thymidine, thymine, alpha-stavudine, and xylo-thymidine.