Particle size is not just a physical property — it directly impacts flowability, compression, dissolution, and bioavailability of a dosage form. That’s why sieve analysis remains one of the most essential tests in pharmaceutical quality control.
What is Sieve Size?
Sieve size refers to the number of openings per inch of mesh.
• Higher sieve number → Smaller opening
• Lower sieve number → Larger opening
Example:
• #10 → Coarse
• #100 → Very fine
Why Sieve Analysis is Important in Pharma?
✔️ Ensures uniform particle size
✔️ Improves powder flow property
✔️ Prevents segregation
✔️ Ensures uniform mixing
✔️ Supports consistent dissolution & bioavailability
⚠️ Poor particle size control may lead to weight variation, hardness issues, and OOS results.
Common Sieve Sizes Used
#10 – 2000 µm → Granules
#20 – 850 µm → Coarse powder
#40 – 425 µm → Medium powder
#60 – 250 µm → Fine powder
#80 – 180 µm → Very fine
#100 – 150 µm → API testing
What is Sieve Analysis?
It is a particle size distribution test where powder is separated using a stack of sieves arranged from larger to smaller openings.
Basic Procedure (Short & Practical)
1️⃣ Weigh 50–100 g sample
2️⃣ Arrange sieves from coarse → fine
3️⃣ Shake for 5–10 minutes
4️⃣ Weigh retained material
5️⃣ Calculate % retained
Key Formula
% Retained = (Weight on sieve / Total sample weight) × 100
Pharmacopeial Compliance
Sieve analysis is defined in:
USP <786>, <811> | BP | IP | Ph. Eur.
✔️ Mandatory for both API and Finished Products
Applications
• API particle size control
• Granulation before compression
• Capsule filling
• Inhalation powders
• Oral suspensions
Interview Tip:
Why is particle size important?
Because it controls flow, compression behavior, dissolution, content uniformity & bioavailability.
Final Thought:
Particle size consistency = Product quality + Regulatory compliance + Patient safety.
Tags:
Pharmacy