Tablet Defects in Pharmaceutical Chemistry

Making tablets might look simple from the outside — press a button, and they pop out perfectly shaped, right? But anyone who’s worked in pharmaceutical manufacturing knows the truth: there’s a lot that can go wrong between formulation and the final product.

From tablets that split like sandwich layers to ones that stick to the punch like bubble gum, every production team has faced these frustrating problems. The good news? Most of these issues have clear causes and even better solutions.

Here’s a breakdown of the most common tablet defects, why they happen, and what you can do to prevent them.

Sources of Tablet Defects in Pharmaceutical Chemistry

Tablet defects can come from both formulation problems and process-related issues. The sources are-

Moisture
Improper drying
High-speed machines
Tools setting problem
Excess use of binders
Lack of proper lubricant selection
Air interaction
Lack of knowledge
Improper training
The abnormal ratio of excipients
Temperature adjustment

Even small slip-ups here can snowball into bigger problems during compression

The Tablet Troubles You’ll Probably Run Into

1. Binding

Let’s start with a classic. Binding happens when granules stick to the die wall during compression. When that tablet is released, the edges appear rough, sometimes with deep, scratch-like marks.

Why it happens: Usually because the lubrication isn’t enough, or it’s not spread evenly throughout the mix.

How to fix it:

Add more lubricant (but not too much)
Make sure it’s mixed in evenly
Adjust granule moisture — sometimes just a little more helps

2. Sticking, Picking, and Filming

These three often get lumped together because they all involve material clinging to the punch faces.

Sticking is when the entire surface of the tablet sticks to the punch.
Picking is a little sneakier — just a small patch of the tablet tears off and sticks.
Filming is a slower build-up over time, creating a thin film on the punch.

Main causes: Too much moisture, poor drying, or sometimes just the punch design itself.

Your move:

Improve drying before compression
Recheck your granule moisture range
Try anti-stick coatings or polish on punches

3. Capping and Lamination

These are the ones that make your stomach drop when you spot them.

Capping is when the top layer of the tablet pops off like a lid.
Lamination is more like slicing — the tablet splits into horizontal layers.

What causes it: Trapped air in the granules is usually to blame. During compression, air gets squeezed in, and when pressure is released, the tablet expands and starts splitting.

Fixes:

Slightly increase granule moisture
Add dry binders (like PVP or gum acacia)
Adjust punch/die fit — too tight can make things worse
Try slowing down the press to give air time to escape

4. Mottling

Ever seen a tablet with blotchy colors or weird light/dark patches? That’s mottling — and it’s not a great look, especially for patient confidence.

Likely reasons:

Dye wasn’t mixed evenly
Some ingredients degrade and change color
Drying too fast causes color migration
Ingredient particle sizes vary too much

What helps:

Use colorants that stay put
Reduce drying temps
Blend thoroughly and consistently
Consider adjusting the solvent or binder system

5. Weight and Hardness Problems

These may not be as visible, but they matter just as much, especially for dosage accuracy.

Why does it happen?

Poor flowability of granules
Uneven feed in the hopper
Fill depth inconsistencies

What to do:

Improve granule flow (sometimes a little colloidal silica helps)
Check and re-check your equipment settings
Keep an eye on press consistency over long runs

Disclaimer

This article is for educational purposes only and is not intended as manufacturing or regulatory advice. Always follow your site’s SOPs and comply with cGMP guidelines.

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Tableting Process: Granulation in the Pharmaceutical Industry