Determination of acyclovir in plasma by solid-phase extraction and column liquid chromatography

Area of Science:

• Pharmacology
• Analytical Chemistry
• Virology

Background:

• Valacyclovir is an L-valyl ester prodrug of acyclovir, an antiherpes virus medication.
• Valacyclovir administration results in 3- to 4.5-fold higher acyclovir bioavailability compared to oral acyclovir.
• Acyclovir is crucial for viral infection prophylaxis in immunocompromised patients, including those with hematologic disorders and organ transplant recipients.

Purpose of the Study:

• To develop and validate a simple, selective liquid chromatographic method for determining acyclovir in plasma.
• To assess the utility of a novel polymeric reversed-phase sorbent for solid-phase extraction of acyclovir.
• To enable therapeutic drug monitoring of acyclovir in patients receiving various coadministered drugs.

Main Methods:

• Solid-phase extraction (SPE) using a new polymeric reversed-phase sorbent.
• Liquid chromatography (LC) for acyclovir determination in plasma.
• Assay validation for precision, accuracy, and sensitivity.

Main Results:

• A mean acyclovir absolute recovery of 90% was achieved during solid-phase extraction.
• The method can accurately measure acyclovir concentrations as low as 62.5 ng/mL using a 250 microL plasma volume.
• No interfering compounds were detected, indicating assay specificity.

Conclusions:

• The developed liquid chromatographic method is suitable for the therapeutic monitoring of acyclovir.
• The new SPE method provides efficient extraction and accurate quantification of acyclovir in plasma.
• Improved acyclovir bioavailability from valacyclovir allows for more convenient dosing regimens, particularly for herpes zoster treatment.