Standard Operating Procedure for Intermediate Moisture Check using IR Balance in API Manufacturing
| Department | API Manufacturing |
|---|---|
| SOP No. | SOP/API/095/2025 |
| Supersedes | SOP/API/095/2022 |
| Page No. | Page 1 of 10 |
| Issue Date | 13/04/2025 |
| Effective Date | 15/04/2025 |
| Review Date | 13/04/2026 |
1. Purpose
To define a standardized procedure for conducting moisture content analysis of intermediate materials using an infrared (IR) moisture balance during the manufacturing of Active Pharmaceutical Ingredients (APIs).
2. Scope
This SOP applies to all in-process intermediate stages in API manufacturing where moisture content needs to be evaluated rapidly and accurately using an IR balance for drying decision-making and process
control.
3. Responsibilities
- Production Chemist: Collect and test intermediate samples using the IR balance.
- QC Analyst: Verify moisture values and ensure proper calibration and use of the instrument.
- QA Officer: Review moisture records and ensure compliance with GMP documentation requirements.
4. Accountability
Production Head is accountable for performing timely and accurate moisture checks. QC Head is accountable for calibration compliance. QA Head ensures adherence to documentation and review requirements.
5. Procedure
5.1 Instrument Verification
- Ensure IR moisture balance is clean, calibrated, and powered ON.
- Verify calibration status from the Calibration Sticker and Calibration Certificate.
- Warm up the instrument for 15 minutes if starting from OFF state.
5.2 Sample Collection
- Collect ~2–3 g of intermediate sample from the drying, filtration, or crystallization stage using a clean spatula.
- Avoid exposure to ambient moisture; sample must be immediately transferred to the balance pan.
- Record batch number, sampling location, time, and initials on the IR Moisture Log (Annexure-1).
5.3 Moisture Check Procedure
- Open the IR moisture balance lid and tare the pan.
- Evenly spread the sample across the pan to ensure uniform drying.
- Close the lid and set the parameters:
- Drying temperature: as per method or 105°C default
- Drying time: Auto or Manual stop after 10–15 minutes
- Start the test and observe drying curve or live result.
- Once stable, record the % Moisture (Loss on Drying).
5.4 Acceptance Criteria and Interpretation
- Compare result with intermediate moisture specification (e.g., NMT 1.5%).
- If within limit, continue with downstream processing.
- If not, continue drying and retest after suitable interval.
- Record decision in BMR and obtain QA concurrence if deviation is observed.
5.5 Cleaning and Shutdown
- Clean the pan and surrounding area using lint-free tissue and soft brush.
- Do not use wet cloth inside the chamber.
- Close the lid and switch off the instrument after use.
6. Abbreviations
- SOP: Standard Operating Procedure
- API: Active Pharmaceutical Ingredient
- IR: Infrared
- LOD: Loss on Drying
- QA: Quality Assurance
- QC: Quality Control
- BMR: Batch Manufacturing Record
7. Documents
- IR Moisture Balance Logbook (Annexure-1)
- Batch Manufacturing Record
- Instrument Calibration Certificate
8. References
- ICH Q7 – GMP for APIs
- USP <731> – Loss on Drying
- 21 CFR Part 211 – US FDA GMP
9. SOP Version
Version: 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | |||
| Department |
11. Annexures
Annexure-1: IR Moisture Balance Logbook
| Date | Batch No. | Stage | Sample Wt. (g) | Moisture (%) | Temp (°C) | Operator | Remarks |
|---|---|---|---|---|---|---|---|
| 13/04/2025 | API-20250413 | Drying | 2.1 | 1.38 | 105 | Within limits |
Revision History:
| Revision Date | Revision No. | Details | Reason | Approved By |
|---|---|---|---|---|
| 01/01/2022 | 1.0 | Initial Release | New Instrument SOP | QA Head |
| 13/04/2025 | 2.0 | Included IR balance specifics, drying range, and decision tree | Process Control Enhancement | QA Head |