High-performance liquid chromatographic assay for etoposide in human plasma

Area of Science:

• Analytical Chemistry
• Pharmacology
• Biochemistry

Background:

• Etoposide is a crucial chemotherapy agent.
• Accurate quantification of etoposide and its metabolites in biological samples is essential for therapeutic drug monitoring and pharmacokinetic studies.
• Existing analytical methods may have limitations in sensitivity, selectivity, or detection techniques.

Purpose of the Study:

• To develop and validate a sensitive and selective reversed-phase high-performance liquid chromatographic (HPLC) assay for etoposide.
• To quantify etoposide in plasma samples.
• To separate etoposide from its known metabolites, including cis-picrolactone, hydroxy derivative, and aglycone.

Main Methods:

• Plasma samples were spiked with etoposide and teniposide (internal standard).
• Etoposide was extracted using chloroform and evaporated.
• Separation was performed using a phenyl mu Bondapak column with a mobile phase of ammonium acetate in methanol:water:acetonitrile.
• Detection was achieved using UV detection at 230 nm.

Main Results:

• The developed HPLC assay demonstrated high sensitivity, quantifying etoposide at concentrations as low as 0.4 micrograms/mL.
• The assay showed good selectivity, effectively separating etoposide from its known metabolites (aglycone, cis-picrolactone, hydroxy derivative) and the internal standard (teniposide).
• Extraction efficiency ranged from 88-94%, with coefficients of variation for intraday and interday analyses at 6%.
• Retention times were 3 min (aglycone), 4 min (etoposide), 4.8 min (cis-picrolactone), and 9 min (teniposide).

Conclusions:

• A robust and reliable reversed-phase HPLC method with UV detection has been successfully developed for the quantification of etoposide in plasma.
• This assay provides an effective alternative to previous methods, offering improved sensitivity and selectivity for etoposide and its metabolites.
• The method is suitable for pharmacokinetic studies and therapeutic drug monitoring of etoposide.