Analysis by ICP Atomic Emission Spectrometry in Accordance with the ICH Q3D Guideline for Elemental Impurities Using ICPE-9820

Importance of Elemental Impurity Analysis in Pharmaceuticals

Ensuring the safety and efficacy of pharmaceutical products requires strict control of elemental impurities. The ICH Q3D guideline identifies 24 toxic metals—such as lead, cadmium, mercury and arsenic—with established permitted daily exposure (PDE) limits. Reliable, sensitive multi-element analysis is essential during drug development and quality control to demonstrate compliance with global regulatory requirements.

Objectives and Study Overview

This study demonstrates the application of inductively coupled plasma atomic emission spectrometry (ICP-AES) using the Shimadzu ICPE-9820 instrument to quantify 24 elemental impurities in two dosage forms: an ophthalmic solution and a solid oral tablet. The goal was to verify that measured concentrations meet ICH Q3D PDE limits and to evaluate method performance via spike-and-recovery tests and detection-limit assessments.

Methodology and Instrumentation

Sample preparation and analysis followed standardized procedures:

• Ophthalmic solution: Acidified with HCl/NH₃ and diluted 1:5; internal standard Y at 0.5 mg/L.
• Tablet: Two tablets (0.2 g total) digested by microwave in HCl/HNO₃, diluted to 20 mL (50×), with internal standards Y (0.5 mg/L) and In (1.0 mg/L).
• Calibration: Internal standard calibration curves for all elements and spike-and-recovery experiments at relevant concentrations.

Used Instrumentation

The Shimadzu ICPE-9820 multi-type ICP-AES was employed under the following conditions:

• Radiofrequency power: 1.2 kW
• Plasma gas flowrate: 10 L/min; auxiliary: 0.6 L/min; carrier: 0.7 L/min
• Sample introduction: Nebulizer 10 with cyclone mist chamber
• Observation: Axial high-sensitivity CCD detection with mini-torch plasma
• Eco mode and vacuum optics to reduce argon consumption

Main Results and Discussion

All 24 elements in both the ophthalmic solution and tablet were below the ICH Q3D PDE limits. Spike-and-recovery rates ranged from 95 % to 107 %, demonstrating accuracy. Detection limits, after accounting for dilution factors, were well below the maximum allowed concentrations. These results confirm that the ICPE-9820 method reliably meets regulatory requirements while delivering high throughput and low operational cost.

Benefits and Practical Applications

Key advantages of this ICP-AES approach include:

• Simultaneous multi-element quantification in a single run
• High sensitivity and precision via axial observation and CCD detection
• Reduced argon consumption through mini-torch design and vacuum optics
• Streamlined sample preparation compatible with routine QC workflows
• Full compliance with ICH Q3D guidelines for pharmaceutical elemental impurities

Future Trends and Opportunities

Advances in instrumentation and automation will further accelerate elemental impurity testing. Emerging areas include coupling ICP-AES with automated sample handling, integration of real-time data analytics for rapid decision-making, and expanded guidelines addressing new drug modalities. Green analytical chemistry initiatives will continue driving reduced gas consumption and alternative plasma sources.

Conclusion

The Shimadzu ICPE-9820 provides a robust, cost-effective solution for quantifying elemental impurities in pharmaceutical formulations. Method performance—demonstrated by low detection limits, high recovery rates, and adherence to ICH Q3D PDE criteria—supports its application in drug development, quality control, and regulatory submissions.

References

• Evaluation and Licensing Division, Pharmaceutical and Food Safety Bureau, Japanese Ministry of Health, Labour and Welfare. Impurities in New Drug Substances No. 1216001.
• Japanese Pharmacopoeia, Sixteenth Edition, First Supplement.
• ICH Q3D Guideline for Elemental Impurities (STEP 4).