A novel method for determining relative response factors using high-performance liquid chromatography with photodiode...

Area of Science:

• Analytical Chemistry
• Pharmaceutical Analysis

Background:

• Accurate determination of impurity relative response factors (RRFs) is crucial for pharmaceutical quality control.
• The purity of reference standards (RS) for cefathiamidine impurities is difficult to obtain, posing a challenge for traditional analytical methods.

Purpose of the Study:

• To develop and validate a reliable method for determining the RRFs of cefathiamidine impurities using High-Performance Liquid Chromatography with Photodiode Array and Evaporative Light Scattering Detection (HPLC-PDA-ELSD).
• To address the challenges associated with unknown reference standard purity and differing mobile phases in HPLC-PDA and HPLC-PDA-ELSD.

Main Methods:

• Utilized HPLC-PDA-ELSD to determine RRFs of cefathiamidine impurities.
• Applied peak area correction to account for variations in mobile phase pH between HPLC-PDA and HPLC-PDA-ELSD.
• Verified the calculated RRF values using quantitative Nuclear Magnetic Resonance (qNMR).

Main Results:

• Successfully determined RRFs for cefathiamidine impurities using the developed HPLC-PDA-ELSD method.
• Peak area correction effectively eliminated response differences due to mobile phase pH variations.
• RRF values obtained through this method were validated by qNMR.

Conclusions:

• The novel HPLC-PDA-ELSD method provides a reliable approach for determining RRFs, particularly when reference standard purity is unknown.
• This method offers a cost-effective, simple, and promising alternative to qNMR for RRF determination.
• Mutual verification with qNMR ensures the accuracy and reliability of the determined RRFs.