impurities, and degradation products.

2. Scope

This procedure is applicable to the Analytical Method Development (AMD) department for CE method development in raw materials, APIs, and drug products where traditional chromatographic methods may be limited or less effective.

3. Responsibilities

• Analytical Scientist: Responsible for method development, buffer optimization, and parameter tuning.
• CE Instrument Operator: Conducts routine operation and maintenance of the CE system.
• QA Officer: Reviews the method validation report and ensures regulatory compliance.
• Head – AMD: Approves the final method and oversees its application in routine analysis.

4. Accountability

The Head of Analytical Method Development is accountable for the scientific integrity and regulatory compliance of CE-based analytical methods.

5. Procedure

5.1 Method Design and Planning

1. Determine analyte properties: charge, pKa, polarity, UV absorbance.
2. Select CE mode:
   • Capillary Zone Electrophoresis (CZE)
   • Micellar Electrokinetic Chromatography (MEKC)
   • Capillary Gel Electrophoresis (CGE)
3. Choose appropriate detection system (e.g., UV, DAD, LIF).

5.2 Buffer System Optimization

1. Select background electrolyte (BGE) buffer based on analyte pKa (e.g., phosphate, borate, acetate).
2. Adjust buffer pH to optimize migration and resolution (target pH range: 2.5 to 9.0).
3. Maintain buffer ionic strength at 10–50 mM to avoid excessive current.
4. Filter and degas all solutions before use.

5.3 Capillary Conditioning and Instrument Setup

1. Flush capillary with:
   • 0.1 N NaOH for 10 minutes
   • Water for 5 minutes
   • Buffer for 10 minutes
2. Use a fused silica capillary (e.g., 50 µm ID, 60 cm total length, 50 cm effective length).
3. Set voltage: 20–30 kV; temperature: 20–25°C; injection: pressure or electrokinetic.

5.4 Sample Preparation

1. Prepare standard and test solutions in water, methanol, or buffer as appropriate.
2. Filter samples through 0.22 µm membrane filter.
3. Keep final concentration within 0.1–1.0 mg/mL.

5.5 System Suitability

1. Inject system suitability mixture containing analyte and known impurities.
2. Evaluate:
   • Resolution (Rs ≥ 1.5)
   • Theoretical plates (≥ 50,000)
   • Repeatability of migration time (RSD ≤ 2%)
3. Record in Annexure-1: System Suitability Log.

5.6 Method Validation

1. Validate per ICH Q2(R2):
   • Specificity – Distinct migration times for all analytes
   • Linearity – R² ≥ 0.995 across 50%–150% range
   • Accuracy – Recovery between 95%–105%
   • Precision – RSD ≤ 2% for peak area and migration time
   • LOD/LOQ – Based on S/N ratio (3:1 and 10:1)
2. Summarize in Annexure-2: Method Validation Report.

5.7 Data Processing and Reporting

1. Use appropriate software for data integration and peak quantification.
2. Use area normalization or calibration curve method as applicable.
3. Archive raw data, processed files, and final reports in controlled storage.

6. Abbreviations

• CE: Capillary Electrophoresis
• CZE: Capillary Zone Electrophoresis
• MEKC: Micellar Electrokinetic Chromatography
• BGE: Background Electrolyte
• LOD: Limit of Detection
• LOQ: Limit of Quantification
• SOP: Standard Operating Procedure

7. Documents

1. System Suitability Log – Annexure-1
2. Method Validation Report – Annexure-2
3. CE Run Logbook – Annexure-3

8. References

• ICH Q2(R2) – Validation of Analytical Procedures
• USP <1053> – Biotechnology-derived Articles—Capillary Electrophoresis
• Ph. Eur. 2.2.47 – Capillary Electrophoresis

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: System Suitability Log

Parameter	Result	Acceptance	Status	Analyst
Resolution	1.8	≥ 1.5	Pass	Sunita Reddy
Migration Time RSD	1.4%	≤ 2%	Pass	Sunita Reddy

Annexure-2: Method Validation Report

Parameter	Result	Criteria	Status
Linearity	R² = 0.997	≥ 0.995	Pass
Recovery	98.5%	95%–105%	Pass

Annexure-3: CE Run Logbook

Run ID	Sample ID	Migration Time (min)	Peak Area	Analyst
CE2025-011	API-B34	5.46	42873	Rajesh Kumar

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Updated buffer system and added CE Run Logbook	Annual SOP Review