Valacyclovir Compounded Oral Suspension

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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Valacyclovir Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of valacyclovir (C₁₃H₂₀N₆O₄).

Prepare Valacyclovir Compounded Oral Suspension 50 mg/mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉).

^a Valtrex 500-mg tablets, Glaxo Wellcome Inc., Research Triangle Park, NC.

^b Paddock Laboratories, Minneapolis, MN.

Calculate the required quantity of each ingredient for the total amount to be prepared. Place the required number of Valacyclovir tablets in a suitable mortar, and comminute to a fine powder. Add the Vehicle in small portions, and triturate to make a smooth paste. Add increasing volumes of the Vehicle to make a valacyclovir liquid that is pourable. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add enough of the Vehicle to bring to final volume, and mix well.

1 ASSAY

PROCEDURE

Mobile phase: Acetonitrile and 5.0 mM sodium acetate (1:99). Adjust with 6 N hydrochloric acid to a pH of 3.0. Filter and degas.

Diluent: 5.0 mM sodium acetate, adjusted with 6 N hydrochloric acid to a pH of 3.0

Standard solution: Dissolve an appropriately weighed amount of USP Valacyclovir Hydrochloride RS in Diluent to be equivalent to 0.2 mg/mL of valacyclovir.

Sample solution: Shake thoroughly by hand each bottle of Oral Suspension. Prepare 0.2 mg/mL of valacyclovir from Oral Suspension and Diluent. Pass through a nylon filter of 0.22-µm pore size.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 3.9-mm x 30-cm; 10-µm packing L1

Flow rate: 3.0 mL/min

Injection volume: 10 µL

System suitability

Sample: Standard solution

[NOTE-The retention time for valacyclovir hydrochloride is about 14 min.]

Suitability requirements

Relative standard deviation: NMT 2.0% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of valacyclovir (C₁₃H₂₀N₆O₄) in the portion of Oral Suspension 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 Valacyclovir Hydrochloride RS in the Standard solution (mg/mL)

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

Acceptance criteria: 90.0%–110.0%

2 SPECIFIC TESTS

pH 〈791〉: 3.2–4.3

3 ADDITIONAL REQUIREMENTS

Packaging and Storage: Package in tight, light-resistant glass containers. Store in a refrigerator.

Beyond-Use Date: NMT 14 days after the date on which it was compounded when stored in a refrigerator

Labeling: Label it to indicate that it is to be well shaken before use, and to state the Beyond-Use Date.

USP Reference Standards 〈11〉