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

Area of Science:

• Pharmacology
• Analytical Chemistry
• Clinical Chemistry

Background:

• Indinavir is a critical HIV protease inhibitor for managing AIDS.
• Accurate therapeutic drug monitoring (TDM) is essential for optimizing indinavir efficacy and patient outcomes.
• Existing methods may require large plasma volumes or lack selectivity.

Purpose of the Study:

• To develop and validate a novel, sensitive, and selective liquid chromatographic method for quantifying indinavir in human plasma.
• To establish a method suitable for routine clinical monitoring of indinavir trough concentrations in patients with Acquired Immunodeficiency Syndrome (AIDS).

Main Methods:

• A rapid solid-phase extraction (SPE) using Oasis HLB sorbent was employed for sample preparation.
• Reversed-phase liquid chromatography (RPLC) with UV detection at 210 nm was used for separation and quantification.
• Weighted least squares linear regression (1/y weighting) was applied for concentration calculations over the 10-800 ng/mL range.

Main Results:

• The method demonstrated high accuracy (102-104%) and precision at the lower limit of quantification (10 ng/mL).
• The limit of detection was as low as 4 ng/mL, ensuring sensitivity for trough level monitoring.
• Mean absolute recoveries for indinavir and internal standard were 66.4% and 80.3%, respectively.
• The assay showed excellent selectivity, with no interference from indinavir metabolites or common co-administered drugs.

Conclusions:

• The developed RPLC method is simple, selective, and accurate for determining indinavir plasma concentrations.
• This assay is well-suited for therapeutic drug monitoring, aiding in the clinical management of AIDS patients on indinavir therapy.