Exploiting pi-acceptors for the determination of thyroid hormones (T3 and T4) using a single interface flow system

Area of Science:

• Analytical Chemistry
• Biochemistry
• Pharmaceutical Analysis

Background:

• Thyroid hormones, levothyroxine (T4) and liothyronine (T3), are crucial for metabolic regulation.
• Accurate quantification of these hormones is essential for diagnosing thyroid disorders and ensuring pharmaceutical efficacy.
• Existing analytical methods may lack automation, speed, or cost-effectiveness.

Purpose of the Study:

• To develop a fully automated methodology for determining T4 and T3.
• To implement a cost-effective and efficient analytical system for thyroid hormone quantification.
• To validate the method's accuracy and precision for pharmaceutical analysis.

Main Methods:

• Development of a fully automated analytical procedure using a single interface flow system (SIFA).
• Exploitation of charge-transfer (CT) complex formation between thyroid hormones (electron donors) and pi-acceptors (chloranilic acid, DDQ).
• Application of Job's method for determining the stoichiometry of CT complexes.

Main Results:

• Linear calibration plots were achieved for T4 (5.0 x 10(-5) to 2.5 x 10(-4) mol L(-1)) and T3 (1.0 x 10(-5) to 1.0 x 10(-4) mol L(-1)).
• High determination frequency of 26 h(-1) with good precision (R.S.D. <4.6% for T4, <3.9% for T3).
• Pharmaceutical formulations showed results statistically comparable to declared amounts (deviations <2.1%) with high recovery rates (96.3–103.7% for T4, 100.1% for T3).

Conclusions:

• The developed automated SIFA method provides a reliable, rapid, and cost-effective means for T4 and T3 determination.
• The method demonstrates excellent accuracy and precision, suitable for quality control of pharmaceutical formulations.
• This automated approach simplifies complex analytical procedures, enhancing efficiency in thyroid hormone analysis.