Quantitative gas-chromatographic flame-ionization method for chloramphenicol in human serum

Area of Science:

• Analytical Chemistry
• Pharmacology
• Clinical Diagnostics

Background:

• Chloramphenicol is a potentially toxic antibiotic requiring careful therapeutic drug monitoring.
• Existing microbiological procedures for chloramphenicol determination lack precision and specificity.

Purpose of the Study:

• To develop and validate a precise and specific flame-ionization gas-chromatographic (GC) method for quantifying chloramphenicol in human serum.
• To establish the suitability of this GC method for routine therapeutic drug monitoring.

Main Methods:

• Serum samples (500 µL) were extracted with ethyl acetate, followed by hexane partitioning to remove nonpolar impurities.
• Chloramphenicol was derivatized to its bis-trimethylsilyl form and analyzed using flame-ionization GC with thiamphenicol as the internal standard.

Main Results:

• The GC method demonstrated high precision with within-run coefficients of variation (CV) of 4.4% (at 41 mg/L) and 9.2% (at 5 mg/L).
• Long-term reproducibility showed a run-to-run variation of 5.1% (at 40 mg/L) over six months (n=24).
• Results correlated strongly (r=0.998) with an established colorimetric method, with mean concentrations of 18.4 mg/L (GC) and 17.6 mg/L (colorimetric) for comparison samples (n=27).

Conclusions:

• The developed flame-ionization GC method is precise, specific, and suitable for routine therapeutic monitoring of serum chloramphenicol concentrations.
• This analytical approach surpasses classical microbiological assays in accuracy and specificity for clinical use.