Evaluation of solid-phase microextraction for the study of protein binding in human plasma samples

Area of Science:

• Analytical Chemistry
• Pharmacology
• Biochemistry

Background:

• Protein binding influences drug efficacy and distribution.
• Accurate measurement of protein binding is crucial for pharmacokinetic studies.
• Traditional methods for assessing protein binding can be complex and time-consuming.

Purpose of the Study:

• To evaluate Solid-phase microextraction (SPME) as a sample preparation technique for studying protein binding of amide-type local anesthetics.
• To compare the performance of different SPME fibers (CW/DVB, polyacrylate, PDMS) for this application.
• To investigate the influence of concentration, pH, and temperature on the protein binding of these anesthetics.

Main Methods:

• Solid-phase microextraction (SPME) coupled with gas chromatography-nitrogen-phosphorous detection.
• Testing of Carbowax/divinylbenzene (CW/DVB), polyacrylate, and polydimethylsiloxane fibers.
• Analysis of ropivacaine, bupivacaine, mepivacaine, prilocaine, and lidocaine in human plasma samples.

Main Results:

• CW/DVB fibers demonstrated the highest recovery rates in plasma samples.
• Protein binding increased with decreasing solute concentration and increasing pH.
• Protein binding decreased with increasing temperature.
• The SPME method showed good correlation, precision, and accuracy within 20% of theoretical values.

Conclusions:

• SPME is a validated and effective sample preparation method for determining protein binding of local anesthetics.
• The developed SPME method yields comparable results to established techniques.
• This approach simplifies the analysis of drug-protein interactions in biological matrices.