Gas-chromatographic micro-scale procedure for theophylline, with use of a nitrogen-sensitive detector

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Pharmacokinetics

Background:

• Accurate theophylline level monitoring is crucial for patient management.
• Previous methods required larger sample volumes, limiting their use in certain populations.
• Pediatric patients often require micro-scale analytical procedures due to limited sample availability.

Purpose of the Study:

• To develop and validate a micro-scale gas chromatography method for theophylline determination.
• To assess the suitability of the method for pediatric patient monitoring.
• To compare the new method with existing techniques.

Main Methods:

• Gas chromatography with nitrogen-sensitive detection.
• Utilized a micro-scale sample volume (10 µL) of serum, plasma, or saliva.
• Simplified extraction procedure enabled by the selective nitrogen detector.

Main Results:

• The method demonstrated high sensitivity, measuring 0.5 mg/L of theophylline with minimal background interference.
• Excellent correlation was observed with a previously established flame ionization method requiring 1 mL of sample.
• Achieved a between-run precision (CV) of 2.8% at a theophylline concentration of 14.8 mg/L.

Conclusions:

• The micro-scale gas chromatography method provides a sensitive and reliable means for theophylline determination.
• The reduced sample volume makes this assay particularly advantageous for pediatric therapeutic drug monitoring.
• This method offers a significant improvement over previous techniques in terms of sample requirement and efficiency.