SOP Guide for Pharma

Gel Manufacturing: SOP for Weighing Micro Quantities of APIs for Gels – V 2.0

Gel Manufacturing: SOP for Weighing Micro Quantities of APIs for Gels – V 2.0

Standard Operating Procedure for Weighing Micro Quantities of APIs in Gel Manufacturing

Department Gel Manufacturing
SOP No. SOP/GM/165/2025
Supersedes SOP/GM/165/2022
Page No. Page 1 of 10
Issue Date 09/06/2025
Effective Date 11/06/2025
Review Date 09/06/2027

1. Purpose

To establish a standard procedure for accurately weighing micro quantities (below 100 mg) of Active Pharmaceutical Ingredients (APIs) used in gel formulation to ensure dosing precision, product quality, and regulatory compliance.

2. Scope

This SOP applies to weighing of APIs in micro quantities used in gel products manufactured at the Gel Manufacturing Department. It includes the use of microbalances, controlled environment protocols, and documentation requirements.

3. Responsibilities

  • Production Chemist: Responsible for execution of weighing activity and recording data.
  • QA Officer: Responsible for
verifying weighed quantities and ensuring compliance with SOP.
  • Engineering: Responsible for maintaining and calibrating microbalances used for weighing.
  • 4. Accountability

    Department Head – Gel Manufacturing and Manager – Quality Assurance are accountable for compliance and implementation of this SOP.

    5. Procedure

    5.1 Pre-Weighing Preparation

    1. Ensure that the microbalance is calibrated and within its valid calibration period.
    2. Clean the balance area using lint-free cloth and 70% IPA prior to activity.
    3. Check balance leveling and ensure the draft shield is functioning properly.
    4. Verify room temperature and humidity are within acceptable limits (as per validation protocol).

    5.2 Material Verification and Documentation

    1. Receive the dispensing slip approved by QA for the specific batch.
    2. Verify API label, batch number, retest date, and quantity required against BMR.
    3. Document material issuance in the raw material logbook and balance logbook.

    5.3 Weighing Procedure

    1. Use pre-cleaned and tared weighing vessels such as watch glasses or plastic scoops with known weights.
    2. Weigh API using micro spatula gently to avoid spillage and static disturbances.
    3. Target quantity should be weighed within ±2% accuracy; reject and reweigh if out of tolerance.
    4. Once weighing is complete, close the sample and tare container to avoid contamination.

    5.4 Transfer of Weighed API

    1. Transfer the weighed API container to manufacturing area in a closed, double-bagged labeled container.
    2. Label should include API name, weight, batch number, date, and analyst signature.
    3. Get QA clearance before transferring material for further processing.

    5.5 Post-Weighing Cleanup and Documentation

    1. Clean the microbalance surface and surroundings after activity.
    2. Log the final weighed quantity in the batch record and in the Weighing Logbook.
    3. QA to review and sign the weighing activity in the logbook and BMR.

    6. Abbreviations

    • API: Active Pharmaceutical Ingredient
    • BMR: Batch Manufacturing Record
    • IPA: Isopropyl Alcohol
    • QA: Quality Assurance

    7. Documents

    1. Micro Weighing Log – Annexure-1
    2. Weighing Checklist – Annexure-2
    3. Material Transfer Label – Annexure-3

    8. References

    • ICH Q7 – Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients
    • GMP Guidelines – WHO TRS 986
    • Internal Quality and Compliance Manual

    9. SOP Version

    Version: 2.0

    10. Approval Section

    Prepared By Checked By Approved By
    Signature
    Date
    Name
    Designation Jr. Production Chemist QA Executive Head – Manufacturing
    Department Gel Manufacturing Quality Assurance Manufacturing

    11. Annexures

    Annexure-1: Micro Weighing Log

    Date API Name Batch No. Target Quantity Actual Quantity Container No. Analyst Signature

    Annexure-2: Weighing Checklist

    Checklist Item Yes/No Remarks
    Microbalance calibrated?
    Room condition verified?
    Correct API selected?
    Container pre-tared?

    Annexure-3: Material Transfer Label

    API Name
    Batch No.
    Weighed Quantity
    Date of Weighing
    Analyst
    Container ID
    QA Clearance

    Revision History

    Revision Date Revision No. Change Description Reason Approved By
    25/05/2022 1.0 Initial release New SOP QA Manager
    09/06/2025 2.0 Revised procedure and annexures Compliance update QA Manager
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