Calibration of Halogen Moisture Analyzer in Pharmaceuticals

1. Introduction

A Halogen Moisture Analyzer determines the moisture content of a sample by heating it with a halogen lamp and continuously measuring the weight loss until a constant mass is achieved.
Calibration ensures that both temperature and weighing accuracy are within specified limits to produce reliable results.

2. Objective

• To verify the instrument’s weighing accuracy and temperature calibration.

• To maintain compliance with GMP and pharmacopeial requirements.

• To ensure consistent, accurate moisture content determination.

3. Types of Calibration

1. Weighing Calibration – Ensures the balance inside the moisture analyzer is accurate.

2. Temperature Calibration – Ensures the halogen heating element achieves the set temperature accurately.

4. Equipment & Materials

• Certified calibration weights (Class E2/F1) for balance calibration

• Certified temperature calibration kit (e.g., temperature sensor probe with traceable certificate)

• Manufacturer’s calibration software or inbuilt calibration mode

• Clean, dry moisture analyzer

5. Calibration Procedure

A. Weighing Calibration

1. Switch on the instrument and allow it to stabilize (warm-up period as per manufacturer).

2. Select balance calibration mode from the menu.

3. Place the certified calibration weight (e.g., 50 g) on the pan.

4. Confirm that the displayed weight matches the standard within tolerance limits.

5. Adjust or recalibrate as per the manufacturer’s instructions if outside tolerance.

B. Temperature Calibration

1. Connect the certified temperature probe to the analyzer.

2. Select temperature calibration in the instrument menu.

3. Set a test temperature (e.g., 100 °C).

4. Allow the instrument to heat and stabilize.

5. Compare the temperature reading on the certified probe to the set temperature.

6. Record the deviation. If outside the acceptable range (commonly ±2 °C), adjust as per manufacturer’s procedure.

6. Calibration Frequency

• Weighing: Daily verification with internal/external calibration weights before use.

• Temperature: Monthly or quarterly, depending on SOP and regulatory needs.

• After repairs or suspected performance issues.

7. Documentation

• Calibration date, time, and analyst name

• Equipment ID and location

• Calibration weight ID and certificate number

• Set vs. observed temperature readings

• Pass/fail result and corrective actions (if any)

• Reviewer’s signature

8. Regulatory Reference

• USP <41> (Balances)

• ISO/IEC 17025 (Calibration standards)

• ICH Q7/Q10 (Equipment calibration)

• Manufacturer’s operating manual

Example Acceptance Statement:

“The halogen moisture analyzer ID: HMA-004 passed both weighing and temperature calibration as per SOP. It is fit for use in pharmaceutical QC moisture determination.”