Fast and sensitive analysis of N-containing bisphosphonates without derivatization using IC-MS

Importance of the Topic

Bisphosphonates represent key active pharmaceutical ingredients in treatment of bone disorders and oncology hypercalcemia. Their high polarity and strong chelating capacity create analytical challenges. Traditional methods often require derivatization and extensive sample preparation that limit throughput and selectivity in complex matrices.

Objectives and Study Overview

This study aimed to develop a rapid method for analysis of nitrogen containing and non nitrogen containing bisphosphonates without derivatization. Using ion chromatography coupled to single quadrupole mass spectrometry in SIM mode, seven bisphosphonates were separated in under fifteen minutes and detected with enhanced selectivity and sensitivity.

Methodology and Instrumentation

• Ion Chromatography System Thermo Scientific ICS 6000 HPIC with RFIC dual pump
• Dionex IonPac AS18 Fast 4 micron column
• Eluent generation by ICS 6000 EG generator using KOH gradient from 40 to 100 mM
• Suppressed conductivity detection via Dionex AERS 500 suppressor in external water mode
• Mass Spectrometry Thermo Scientific ISQ EC single quadrupole with HESI II probe operating in negative ESI SIM mode
• No make up solvent or desolvation agent required
• Chromeleon CDS software for data acquisition and processing

Main Results and Discussion

SIM extraction resolved coeluting peaks seen in conductivity traces and allowed individual quantification. Calibration curves were linear between 0.01 and 1 ng per microliter indicating wide dynamic range. Limits of quantification around 10 microgram per liter were achieved for a 5 microliter injection with signal to noise ratios between 5 and 22. The method demonstrated robustness and high chromatographic selectivity.

Benefits and Practical Applications

This IC MS approach eliminates derivatization steps and simplifies sample preparation. It provides high sensitivity for trace analysis in complex matrices such as plasma. The rapid throughput and compatibility with standard ion chromatography hardware make the method well suited for pharmaceutical quality control and doping control laboratories.

Future Trends and Possibilities

Advances in high resolution mass spectrometry and automated sample handling may further enhance sensitivity and specificity. Expansion to additional bisphosphonate analogues and multiplexed assays could support broader pharmacokinetic and toxicology studies. Integration with online sample cleanup is a promising direction.

Conclusion

The presented IC MS method offers fast sensitive and derivatization free analysis of N containing and other bisphosphonates. It extends standard HPIC instrumentation with mass detection to achieve low quantification limits and high selectivity in under fifteen minutes.

References

• Zacharis CK Tzanavaras PD Determination of bisphosphonate active pharmaceutical ingredients in pharmaceuticals and biological material a review of analytical methods J Pharm Biomed Anal 2008 48 483 496
• Liu XK Fang JB Cauchon N Zhou P Direct stability indicating method development and validation for analysis of etidronate disodium using a mixed mode column and charged aerosol detection J Pharm Biomed Anal 2008 46 639 644
• Wang J Schnute WC Quantitative determination of bisphosphonate pharmaceuticals and excipients by capillary IC MS Thermo Scientific Application Note 1001