Analysis of Residual Solvents in drug products

Significance of the topic

Residual solvents in pharmaceutical products can pose safety and quality risks if not properly controlled. Analysis according to USP <467> ensures that trace levels of potentially toxic organic solvents remain below prescribed limits, safeguarding patient health and ensuring regulatory compliance.

Objectives and Study Overview

This application note demonstrates a combined gas chromatography–flame ionization detection (GC-FID) and headspace (HS) sampling method for quantifying Class 2B residual solvents in drug products. The study follows USP <467> Procedure A, targeting eight solvents including hexane, nitromethane and chloroform.

Instrumentation

• Gas chromatograph: Shimadzu Nexis GC-2030
• Detector: FID-2030
• Headspace sampler: HS-20
• Column: SH-I-624Sil MS (30 m × 0.32 mm I.D., 1.8 µm film)

Methodology

For GC-FID analysis, samples are injected in split mode (1:5) with helium carrier gas at a constant linear velocity of 35 cm/s. The column temperature program starts at 40 °C (20 min), ramps at 10 °C/min to 240 °C, and holds for 20 min. Detector temperature is set to 250 °C. Headspace conditions include an oven at 80 °C, sample line at 110 °C and transfer line at 120 °C. Twenty-milliliter vials are pressurized to 75 kPa and equilibrated for 60 min before injection.

Main Results and Discussion

The combined GC-FID and HS-GC method achieved baseline separation of the eight Class 2B solvents within a 60-minute run. Calibration curves exhibited good linearity across the required concentration ranges. The method demonstrated precision with relative standard deviations below 5 % and detection limits meeting USP criteria.

Benefits and Practical Applications

The described method provides a reliable, reproducible protocol for routine quality control of residual solvents in pharmaceuticals. Its compatibility with standard GC-FID instrumentation and headspace modules makes it accessible for QC laboratories, facilitating compliance with pharmacopoeial standards.

Future Trends and Possibilities

Advancements may include faster temperature ramps, shorter columns with similar selectivity, and integration of automated sample preparation. Emerging detectors such as mass spectrometry can offer enhanced sensitivity and compound identification. Data-driven optimization and artificial intelligence may further streamline method development and regulatory reporting.

Conclusion

This application note confirms that the Nexis GC-2030 coupled with an HS-20 sampler and SH-I-624Sil MS column meets USP <467> Procedure A requirements for Class 2B solvents. The protocol ensures accurate, precise and efficient residual solvent analysis, supporting pharmaceutical quality assurance.

References

• Shimadzu Application News G290 (JP, ENG)
• Shimadzu Corporation, First Edition: Sep. 2022, ERAS-1000-0308