Colour uniformity in film-coated tablets is a critical quality parameter. It is directly linked to regulatory compliance, patient safety, and brand trust.

Film coating tablet manufacturers cannot depend on luck to achieve color uniformity. It is the result of process discipline, formulation science, and controlled dispersion technology. In this blog, we have explained how Novo Excipient, a leading tablet coating manufacturer, achieves colour uniformity each and every time. 

First, let us understand why uniform colour is so important in film coating systems.

Why Color Uniformity Matters in Film Coating?

Cosmetic film coating is one of the most technically demanding coating applications, yet one in which manufacturers heavily invest. 

This is because colour determines much more than aesthetics in film-coated tablets:

1. Patient compliance: Color helps patients recognize and accept medication.
2. Prevention of errors: Distinct, consistent hues reduce confusion between strengths or brands
3. Marketing: Visual consistency builds recall and trust

For example, when you think of an Amoxicillin 500mg tablet, you automatically imagine a pink-colored tablet. 

Challenge of Maintaining Colour Consistency:

The challenge in colour coating is never the choice of colour, but maintaining the same colour, especially during scale-up, equipment changes, or multiple manufacturing facilities. 

Minor inconsistencies in film coating on tablets can lead to visible shade variation, leading to concerns during audit or product acceptance in regulated markets. This is where ΔE (Delta E) becomes critical.

Understanding ΔE in Film Coating

Film coating tablet manufacturers measure color uniformity using ΔE. It is a numerical value that defines color difference. The lower the ΔE value, the smaller the color difference. A ΔE of 0 means the colors are identical.

It is calculated using color measurements taken in the CIE Lab color space, an internationally recognized system designed to approximate human vision. 

Here’s how it works:

Every color is defined by three values in the Lab system:

1. L (Lightness) Ranges from 0 (black) to 100 (white)
2. a (Red-Green axis): Positive values are red, negative values are green
3. b (Yellow-Blue axis): Positive values are yellow, negative values are blue

Changes in lightness (ΔL) and color coordinates (Δa and Δb) of film-coated tablets are used to calculate the value ΔE via a formula.

1. ΔE < 1.0: Color difference is not perceptible to the human eye. 
2. ΔE 1.0 – 2.0: Color difference is noticeable only under direct comparison by trained observers. Generally acceptable.
3. ΔE 2.0 – 3.5: Color difference is noticeable to the average observer.
4. ΔE > 3.5: Color difference is clearly visible.

How Film Coating Tablet Manufacturers Maintain Delta E?

Achieving and maintaining tight ΔE values requires a systematic approach throughout the manufacturing process. While each coating manufacturer have their own protocols to maintain this value, there are a few basic steps that they follow:

1. Set a reference standard from an approved batch
2. Control raw material quality
3. Test colour systems of the new batch against a retained reference sample
4. Plot ΔE values over time on control charts 
5. Establish limits 
6. If the value drifts, immediately investigate potential causes
7. Document all color measurements and ΔE calculations in batch manufacturing records.

At Novo Excipients, we strongly believe that colour uniformity is less of a luck factor and more of a discipline factor. From product development to full-scale launch, we maintain tight ΔE values for consistent, reliable film coating on tablets.

With ready-Mix film coatings for tablets like Novo-Mix, achieving color uniformity becomes even easier. This consistency is achieved through advanced dispersion technology, stringent quality checks, and tight ΔE control.

Conclusion:

In pharmaceutical manufacturing, visual consistency reflects process excellence. Achieving colour uniformity is not about fixing colour issues when they arise. It is about designing consistency in the tablet film coating system.

Ready to improve your film coating consistency? Partner with Novo Excipients to achieve consistent coating results.