physiological fluids.

2. Scope

This SOP applies to all parenteral formulations developed in the Analytical Method Development (AMD) department including solutions, emulsions, and lyophilized products intended for reconstitution, for use in quality control, formulation development, and stability studies.

3. Responsibilities

• Analytical Scientist: Develops the method and verifies performance against reference standards.
• Lab Analyst: Prepares samples, performs testing, and documents osmolality values.
• QA Officer: Ensures compliance of osmolality data with regulatory requirements.
• Head – AMD: Approves method development reports and authorizes implementation.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring accurate and repeatable osmolality testing is performed and documented in compliance with pharmacopeial and ICH guidelines.

5. Procedure

5.1 Instrument Requirements

1. Use a calibrated freezing point depression osmometer with microprocessor control.
2. Ensure the instrument is certified for pharmaceutical use and has auto-calibration capability.
3. Document calibration records in Annexure-1: Osmometer Calibration Log.

5.2 Calibration and Control Standards

1. Use three-point calibration:
   • Low (100 mOsm/kg)
   • Medium (290 mOsm/kg)
   • High (1000 mOsm/kg)
2. Perform calibration daily or before each batch analysis.
3. Verify with control standards (e.g., USP reference standards) within ±3% of label claim.

5.3 Sample Preparation

1. Allow samples to equilibrate to room temperature (25 ± 2°C) before analysis.
2. Filter samples through 0.22 µm syringe filter if applicable (especially for emulsions or suspensions).
3. Transfer 50–100 µL of sample into a clean osmolality measurement tube or ampoule.

5.4 Measurement Procedure

1. Insert sample tube into osmometer chamber.
2. Initiate the measurement cycle and allow the system to complete freezing, supercooling, and thawing stages.
3. Record the measured osmolality value in mOsm/kg.
4. Perform duplicate testing for each sample and average the results.
5. Log data in Annexure-2: Osmolality Test Record.

5.5 Acceptance Criteria

1. Osmolality of isotonic parenterals: 270–310 mOsm/kg
2. Deviation between replicate measurements: ≤ 2%
3. For hypertonic/hypotonic formulations, acceptable osmolality must be justified in formulation design report.

5.6 Method Validation

1. Validate the osmolality method as per ICH Q2(R2) and USP <785>:
   • Precision: RSD ≤ 2% (intra- and inter-day)
   • Accuracy: Recovery of spiked standards 98–102%
   • Linearity: R² ≥ 0.998 across the range 100–1000 mOsm/kg
   • Robustness: Consistency with different analysts and sample volumes
2. Summarize validation data in Annexure-3: Method Validation Summary.

6. Abbreviations

• AMD: Analytical Method Development
• USP: United States Pharmacopeia
• mOsm/kg: Milliosmoles per kilogram
• RSD: Relative Standard Deviation
• SOP: Standard Operating Procedure

7. Documents

1. Osmometer Calibration Log – Annexure-1
2. Osmolality Test Record – Annexure-2
3. Method Validation Summary – Annexure-3

8. References

• USP <785> – Osmolality and Osmolarity
• ICH Q2(R2) – Validation of Analytical Procedures
• European Pharmacopoeia – General Chapters: Osmolality

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Osmometer Calibration Log

Date	Standard (mOsm/kg)	Observed Value	% Deviation	Analyst
18/05/2025	290	287.6	-0.83%	Sunita Reddy

Annexure-2: Osmolality Test Record

Batch No.	Sample ID	Measured Osmolality (mOsm/kg)	Acceptance Limit	Status
INJ-231	Vial-1	293	270–310	Complies

Annexure-3: Method Validation Summary

Parameter	Result	Criteria	Status
Precision	RSD = 1.5%	≤ 2%	Pass
Accuracy	99.4%	98–102%	Pass
Linearity	R² = 0.9991	≥ 0.998	Pass

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Included expanded acceptance criteria and updated annexures	Regulatory alignment and clarity