Analysis of phenothiazines in human body fluids using disk solid-phase extraction and liquid chromatography

Area of Science:

• Analytical Chemistry
• Pharmacology

Background:

• Phenothiazine derivatives are crucial in treating various psychiatric disorders.
• Accurate quantification of these drugs in biological matrices is essential for therapeutic drug monitoring and pharmacokinetic studies.

Purpose of the Study:

• To develop and validate a solid-phase extraction (SPE) method for the simultaneous determination of seven phenothiazine derivatives in human plasma and urine.
• To establish a sensitive and reliable liquid chromatography-ultraviolet (LC-UV) detection method for these compounds.

Main Methods:

• Seven phenothiazine derivatives were extracted from human plasma and urine samples using disk solid-phase extraction (SPE) with Empore C18 cartridges.
• Elution was performed using a chloroform-acetonitrile mixture, followed by determination using liquid chromatography with gradient elution.
• Detection was achieved via ultraviolet absorption at 250 nm using a SymmetryShield RP8 column.

Main Results:

• The SPE method demonstrated good recoveries for the phenothiazine derivatives, ranging from 64.0-89.9% in plasma and 65.1-92.1% in urine.
• Excellent linearity was observed, with low detection limits (0.021-0.30 µg/mL in plasma, 0.017-0.30 µg/mL in urine).
• High precision was achieved, with within-day and day-to-day coefficients of variation below 9.0% and 14.9%, respectively.

Conclusions:

• The developed SPE-LC-UV method is effective for the simultaneous extraction and determination of seven phenothiazine derivatives in human plasma and urine.
• This method provides a reliable and sensitive approach for analyzing phenothiazine drugs in biological samples, supporting clinical and research applications.