Fluphenazine determination in human plasma by a sensitive gas chromatographic method using nitrogen detector

Area of Science:

• Pharmacology
• Analytical Chemistry
• Clinical Chemistry

Background:

• Fluphenazine is an antipsychotic medication used to treat various mental health conditions.
• Accurate measurement of fluphenazine in human plasma is crucial for therapeutic drug monitoring.
• Existing methods may lack the sensitivity or specificity required for precise quantification at therapeutic levels.

Purpose of the Study:

• To develop and validate a sensitive gas chromatographic method for determining fluphenazine concentrations in human plasma.
• To quantify fluphenazine levels in patients receiving the drug via oral or intramuscular routes.
• To investigate interindividual variability in fluphenazine pharmacokinetics.

Main Methods:

• A sensitive gas chromatographic method utilizing a nitrogen detector was developed.
• Fluphenazine was derivatized to its acetyl form for enhanced detection.
• Perphenazine served as an internal standard for accurate quantification.
• Gas chromatography-mass spectrometry (GC/MS) was employed for derivative identification.

Main Results:

• The method demonstrated good within-day precision with a coefficient of variation of 6.7% for concentrations ranging from 0.5 to 10 ng/ml.
• Fluphenazine concentrations were successfully measured in plasma samples from patients undergoing oral or intramuscular therapy.
• Significant interindividual variations in both plasma drug levels and elimination half-lives were observed among patients on identical dosages.

Conclusions:

• The developed gas chromatographic method is sensitive and reliable for quantifying therapeutic concentrations of fluphenazine in human plasma.
• The findings highlight substantial interindividual variability in fluphenazine pharmacokinetics, necessitating personalized dosing strategies.
• This method facilitates improved therapeutic drug monitoring for fluphenazine, potentially optimizing patient outcomes.