Elixir Department: SOP for Titration of pH Buffers – V 2.0

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Elixir Department: SOP for Titration of pH Buffers – V 2.0

Standard Operating Procedure for Titration of pH Buffers Used in Elixir Manufacturing

Department Elixir Department
SOP No. SOP/ELX/206/2025
Supersedes SOP/ELX/206/2022
Page No. Page 1 of 9
Issue Date 11/04/2025
Effective Date 15/04/2025
Review Date 11/04/2026

1. Purpose

To define the procedure for preparation, titration, and standardization of pH buffer solutions used during elixir manufacturing and in-process quality control to ensure accurate pH control and compliance with pharmacopeial requirements.

2. Scope

This SOP applies to all buffer solutions prepared and titrated for use in elixir formulation pH adjustments, equipment calibration, and analytical procedures within the Elixir Department.

3. Responsibilities

  • QC Chemist:
    • Prepare and titrate buffer solutions as per standard procedure.
    • Ensure all glassware and reagents are appropriately labeled and calibrated.
  • Production Staff:
    • Use standardized buffer solutions for pH adjustments during manufacturing.
  • QA Officer:
    • Verify records and approve buffer solutions for use.
See also  Elixir Department: SOP for Color and Odor Testing - V 2.0

4. Accountability

The QC Head is accountable for the accuracy of buffer preparation and standardization. QA ensures adherence to validated methods and GMP guidelines.

5. Procedure

5.1

Buffer Selection and Preparation
  1. Select appropriate buffer based on required pH range (e.g., acetate for pH 4.0–5.5, phosphate for pH 6.0–8.0).
  2. Use analytical grade chemicals and freshly prepared purified water.
  3. Prepare buffer using weight/volume or molarity-based formula as per pharmacopeial standards.
  4. Label all solutions with:
    • Name of buffer
    • pH value
    • Date of preparation
    • Prepared by

5.2 Titration Procedure

  1. Calibrate pH meter as per SOP/QC/PHM/001 using standard pH 4.0, 7.0, and 9.2 buffers.
  2. Measure 50 mL of the prepared buffer and place in a beaker.
  3. Insert the pH electrode and magnetic stirrer (if applicable).
  4. Titrate slowly with titrant (e.g., NaOH for acidic buffers or HCl for basic buffers) while recording pH at each addition.
  5. Continue until the pH changes slowly and reaches the targeted pH ± 0.05 units.

5.3 Recording Results and Standardization

  1. Document the volume of titrant used and pH observed at each stage in the Buffer Titration Logbook (Annexure-1).
  2. Plot titration curve (if required) and confirm buffering capacity.
  3. Mark standardized buffer with “Ready to Use” label and store at 2–8°C (if applicable).

5.4 Frequency of Titration

  1. Each freshly prepared buffer must be titrated and standardized prior to use.
  2. Retitrate after 7 days or as per stability data, whichever is earlier.

5.5 Precautions

  1. Do not use expired reagents or uncalibrated instruments.
  2. Do not reuse titrated buffer solutions for batch pH adjustment.
  3. Use personal protective equipment during titration and disposal.

5.6 Documentation

  1. Record all details in Buffer Titration Logbook (Annexure-1).
  2. Maintain calibration and preparation certificates of instruments and reagents.
  3. Attach buffer usage records to respective BMRs when used in production.

6. Abbreviations

  • SOP: Standard Operating Procedure
  • QA: Quality Assurance
  • QC: Quality Control
  • BMR: Batch Manufacturing Record
  • pH: Potential of Hydrogen

7. Documents

  1. Buffer Titration Logbook (Annexure-1)
  2. pH Meter Calibration Log
  3. Batch Manufacturing Record (BMR)

8. References

  • USP General Chapter <791> – pH
  • ICH Q2(R1) – Validation of Analytical Procedures
  • 21 CFR Part 211.160 – Laboratory Controls

9. SOP Version

Version: 2.0

10. Approval Section

Prepared By Checked By Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Buffer Titration Logbook

Date Buffer Type Theoretical pH Observed pH Titrant Used Volume Added Result Tested By QA Verified
11/04/2025 Phosphate Buffer 7.4 7.38 0.1N NaOH 0.35 mL Pass Rajesh Kumar Sunita Reddy

Revision History:

Revision Date Revision No. Revision Details Reason for Revision Approved By
01/01/2024 1.0 Initial Release New SOP QA Head
11/04/2025 2.0 Added titration curve evaluation step Process Optimization QA Head
Elixers V 2.0 Tags:, , , , , , , , , , , , , , , , , , , , , , , ,