Acyclovir Injection

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

Acyclovir Injection contains acyclovir sodium equivalent to NLT 90.0% and NMT 110.0% of the labeled amount of acyclovir (C₈H₁₁N₅O₃).

2 IDENTIFICATION

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

B. The UV spectrum 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

Mobile phase: 3 mL/L of glacial acetic acid in water

Standard stock solution: 2 mg/mL of USP Acyclovir RS in 0.1 N sodium hydroxide. Sonicate, if necessary, to dissolve prior to final dilution.

Standard solution: 0.1 mg/mL of USP Acyclovir RS in water from the Standard stock solution

Sample stock solution: Nominally 2 mg/mL of acyclovir prepared as follows. Transfer 4 mL of Injection to a 100-mL volumetric flask and dilute with 0.1 N sodium hydroxide to volume.

Sample solution: 0.1 mg/mL of acyclovir in water prepared from the Sample stock solution

3.2 Chromatographic system

Mode: LC

Detector: UV 254 nm. For Identification B, use a diode array detector in the range of 200–400 nm.

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

Column temperature: 40°

Flow rate: 1.8 mL/min

Injection volume: 10 μL

Run time: NLT 1.5 times the retention time of acyclovir

3.3 System suitability

Sample: Standard solution

3.4 Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0%

3.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of acyclovir (C₈H₁₁N₅O₃) in the portion of Injection taken:

Result = (r_u/r_s ) × (C_s/C_u) × 100

r_u = peak response of acyclovir from the Sample solution

rs = peak response of acyclovir from the Standard solution

C_s = concentration of USP Acyclovir RS in the Standard solution (mg/mL)

C_u= nominal concentration of acyclovir in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0%

4 IMPURITIES

4.1 Organic Impurities

Solution A: 1.36 g/L of potassium dihydrogen phosphate in water. Adjust with 10% phosphoric acid to a pH of 3.0.

Solution B: Methanol

Mobile phase: See Table 1.

Table 1

Diluent: 3 mL/L of glacial acetic acid in water

Sensitivity solution: 0.5 μg/mL of USP Acyclovir RS in Diluent. Sonicate, if necessary, to dissolve prior to final dilution.

Standard stock solution A: 0.0265 mg/mL of USP Acyclovir RS in Diluent. Sonicate, if necessary, to dissolve prior to final dilution.

Standard solution A: 0.00265 mg/mL of USP Acyclovir RS in Diluent, from Standard stock solution A

Standard stock solution B: 0.035 mg/mL of USP Guanine RS prepared as follows. Transfer 3.5 mg of USP Guanine RS to a 100-mL volumetric flask and add about 25 mL of 0.1 N sodium hydroxide. Sonicate, if necessary, to dissolve and dilute with water to volume.

Standard solution B: 0.0035 mg/mL of USP Guanine RS in Diluent, from Standard stock solution B

Sample solution: Nominally 0.5 mg/mL of acyclovir in Diluent prepared as follows. Transfer 2 mL of Injection to a 200-mL volumetric flask and dilute with Diluent to volume.

4.2 Chromatographic system

Mode: LC

Detector: UV 254 nm

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

Temperatures

Autosampler: 6°

Column: 40°

Flow rate: 1 mL/min

Injection volume: 50 μL

4.3 System suitability

Samples: Sensitivity solution, Standard solution A, and Standard solution B

4.4 Suitability requirements

Relative standard deviation: NMT 2.0% for acyclovir, Standard solution A; NMT 2.0% for guanine, Standard solution B

Tailing factor: NMT 2.0 for acyclovir, Standard solution A; NMT 2.0 for guanine, Standard solution B Signal-to-noise ratio: NLT 10 for acyclovir, Sensitivity solution

4.5 Analysis

Samples: Standard solution A, Standard solution B, and Sample solution

Calculate the percentage of guanine in the portion of Injection taken:

Result = (r_u/r_s) × (C_s/C_u) × 100

r_u = peak response of guanine from the Sample solution

r_s = peak response of guanine from the Standard solution B

C_s = concentration of USP Guanine RS in Standard solution B (mg/mL)

C_u = nominal concentration of acyclovir in the Sample solution (mg/mL)

Calculate the percentage of any individual impurity in the portion of Injection taken:

Result = (r_u/r_s) × (C_s/C_u) × 100

r_u = peak response of any individual impurity from the Sample solution

r_s = peak response of acyclovir from the Standard solution A

C_s = concentration of USP Acyclovir RS in Standard solution A (mg/mL)

C_u = nominal concentration of acyclovir in the Sample solution (mg/mL)

Acceptance criteria: See Table 2.

Table 2

^a Bis({9-[(2-hydroxyethoxy)methyl]guanine}-N²-yl)methane.

^b Total impurities excludes guanine.

5 SPECIFIC TESTS

Bacterial Endotoxins Test 〈85〉: Meets the requirements

Particulate Matter in Injections 〈788〉: Meets the requirements

Sterility Tests 〈71〉: Meets the requirements

pH 〈791〉: 10.85–11.50

Other Requirements: It meets the requirements in Injections and Implanted Drug Products 〈1〉.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in single-dose containers, preferably of Type I glass. Store at controlled room temperature.

USP Reference Standards 〈11〉

USP Acyclovir RS

USP Guanine RS

2-Amino-1,7-dihydro-6H-purin-6-one.

C₅H₅N₅O 151.13