viscosity, physical stability, and content uniformity.

2. Scope

This SOP applies to the Analytical Method Development (AMD) department for pharmaceutical emulsions (e.g., oil-in-water, water-in-oil) and suspensions (oral, injectable, topical) at all stages of formulation development.

3. Responsibilities

• Analytical Scientist: Responsible for designing, executing, and validating analytical tests for emulsions and suspensions.
• Formulation Scientist: Provides formulation details and proposed specifications for method design.
• QA Officer: Reviews analytical reports and validation results for compliance.
• Head – AMD: Approves the method for release and submission after evaluation of performance criteria.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring that methods developed for emulsions and suspensions are scientifically justified, validated, and meet regulatory expectations.

5. Procedure

5.1 Method Planning and Design

1. Obtain formulation details including:
   • Type of dispersion (emulsion or suspension)
   • Phase composition and active pharmaceutical ingredient (API)
2. Identify Critical Quality Attributes (CQAs):
   • Particle/Droplet Size
   • Viscosity
   • Drug Content
   • Physical Stability
   • pH and appearance

5.2 Droplet/Particle Size Analysis

1. Use Dynamic Light Scattering (DLS) or Laser Diffraction.
2. Dilute samples appropriately using dispersion medium to avoid multiple scattering.
3. Measure mean size, distribution range, and polydispersity index (PDI).
4. Record results in Annexure-1: Size Analysis Log.

5.3 Drug Content (Assay)

1. Accurately weigh the sample and dilute with suitable solvent.
2. Centrifuge or filter to separate undissolved materials (if suspension).
3. Analyze using validated HPLC or UV method.
4. Acceptance range: 95.0% to 105.0% of label claim.

5.4 Viscosity Measurement

1. Use Brookfield viscometer with appropriate spindle.
2. Maintain sample at 25 ± 2°C.
3. Record viscosity at different shear rates if required.
4. Enter values in Annexure-2: Viscosity Log.

5.5 pH and Appearance

1. Measure pH using calibrated pH meter.
2. Visually inspect for:
   • Phase separation
   • Color changes
   • Sedimentation or caking (in suspensions)
3. Photograph visual tests for records (if needed).

5.6 Physical Stability Study

1. Store samples under:
   • Accelerated (40°C ± 2°C/75% RH)
   • Room temperature (25°C ± 2°C/60% RH)
2. Evaluate at defined intervals for:
   • Phase separation
   • Precipitation
   • Color and odor
3. Record observations in Annexure-3: Stability Monitoring Sheet.

5.7 Method Validation

1. Validate assay and particle size method as per ICH Q2(R2).
2. Include:
   • Specificity
   • Linearity
   • Precision (repeatability and intermediate)
   • Accuracy
   • Robustness
3. Summarize data in Annexure-4: Method Validation Report.

6. Abbreviations

• HPLC: High Performance Liquid Chromatography
• DLS: Dynamic Light Scattering
• PDI: Polydispersity Index
• RH: Relative Humidity
• SOP: Standard Operating Procedure

7. Documents

1. Size Analysis Log – Annexure-1
2. Viscosity Log – Annexure-2
3. Stability Monitoring Sheet – Annexure-3
4. Method Validation Report – Annexure-4

8. References

• ICH Q2(R2) – Validation of Analytical Procedures
• USP <729> – Globule Size Distribution in Emulsions
• FDA Draft Guidance on Semisolid Topical Products

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Size Analysis Log

Sample ID	Mean Size (nm)	PDI	Analyst
EML/2025/015	168.4	0.241	Sunita Reddy

Annexure-2: Viscosity Log

Sample ID	Spindle	RPM	Viscosity (cP)	Analyst
SUS/2025/009	LV-2	30	850	Rajesh Kumar

Annexure-3: Stability Monitoring Sheet

Time Point	Condition	Observation	Analyst
30 Days	40°C/75% RH	Clear phase separation observed	Ajay Verma

Annexure-4: Method Validation Report

Parameter	Result	Acceptance Criteria	Status
Linearity	R² = 0.9992	≥ 0.999	Pass
Accuracy	98.2% – 101.6%	98% – 102%	Pass

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Included stability criteria and validation log	Annual SOP Review