Defective Color Variation In Coated Tablets

• Defective Color Variation in Coated Tablets

The collection of tablet coating faults is comprehensive, encompassing a wide range of flaws seen during the practical application of the coating process.

This article will go over a very typical tablet coating problem that is typically encountered during the surface coating of color tablets.

• Why Is Color Used In Coating Suspension?

To conduct our tablet coating activity more quickly also without color variation faults, one typical opinion that people associated with tablet coating systems have is that there should be a white coating solution rather than a color coating suspension.

So, why do we employ various colors in tablet coating preparations?

The response is that the usage of color in tablet coating formulas is advised for the factors listed below.

• To produce tablets extra attractive, we incorporate color into our coating formulations.
• Colors are included to tablet coating formulas to reduce the possibility of a combination.
• Assume we have just a drug with two distinct levels, 5 mg and 10 mg, that are identical in tablet weight and form and are crushed through the same tooling, 9 mm.To reduce the possibility of mixing, we might add color to the coating composition of one strength.
• Colors are applied to the tablet coating suspension to aid in brand recognition.
• Colored tablets are easier for aged or less informed consumers to recall.
• In competing with competitive companies, color could also be added to coating recipe.
• To conceal the color of API and provide consistent color.

• What Exactly Is Color Variation?

Color variation is a typical tablet coating flaw in which the color of the tablets varies.

Color variation is a coating problem, so let’s talk about what the phrase for disorder free color coating is.

Color homogeneity is a phrase used to describe smooth and accurate color coating. Color uniformity indicates that all tablets in a batch are the same color and that there is no color variation between individual tablets and tablets from various batches of the same product.

Color uniformity is obtained when color is correctly distributed over the surface of the tablet and is connected to the weight gain following the coating process.

If the weight growth of the drugs is smaller than the required values, the color of the pills may not be uniform  because of less color buildup over the tablets.

• Color Variation Causes And Treatment

Now we’ll look into why color variation happens throughout the tablet film formation and how to avoid or manage it.

The below are the main causes of color variance.

Temperature of the Inlet Air:When the inlet air temperature exceeds the acceptable setpoint, the color and coating material are lost due to the quick evaporation of the solvent. As a consequence of the over drying effect caused by the quick vaporization of the solvent, less color and coating material is placed on the sample surface.

Solution

• Boost the spraying rate without raising the inlet air temperature.
• Lower the suction of the outflow to decrease coating failure.

Temperature of the Tablet Bed:

An unexpected rise in tablet bed temperature might even result in different varieties of coated tablets due to the degradation of color-containing coating material.

Solution

• Lower the temperature of the incoming air.
• Raise the spray rate to lower the temperature of the tablet bed.

Distance from gun to bed:

Increasing range between spray guns and tablet bed may indeed create variability in coated tablets because less coating sample containing color is placed on tablet surface as a result of solvent evaporation.

Solution

• Keep a secure distance between both the spray guns and the tablet bed.
• If you need to cover more ground, raise the Spray rate.

Spray Volume:

• If our spray rate goes down and the input air temperature or tablet bed temperature is higher, the dusty atmosphere may cause color change, which is a signal of quick solvent evaporation.
• The solvent evaporates prior contacting the tablet surface because of early solvent evaporation, and the coating material is not effectively applied over the surface of rotating tablets.

Solution

• Boost the spray rate.
• Reduce the temperature of the incoming air.

Pan Rate:

The speed of the coating pan can also have an impact on the color homogeneity of the coated tablets. Slow pan speed can cause enormous unequal dark color patches on the surface of spinning tablets, which can take longer to become equal. The explanation for this is that when the pan speed is reduced and the spray rate is high the contact time of the applied spray increases, causing it to not distribute equally.

Solution

• Raise the pan speed and spray rate gradually.
• Higher pan speed causes high tablet rotation, which reduces contact time while increasing the number of showers per minute and applying color to a larger surface area of the tablet in a short time.

Exhaust:

If the coating pan exhaust hole is too large, color and coating material will be lost.

Solution

Exhaust apertures should be adjusted to reduce coating material loss.

• Summary

Tablet color fluctuation is a frequent tablet coating fault caused by the loss of color as well as coating material owing to incorrect management of tablet coating process conditions.

To minimize product loss and achieve color homogeneity in a batch, always regulate temperature and spray rate in sync.

To achieve a smooth coating process for color tablets, the coating pan outlet air or exhaust, pan speed, and spray guns to tablet bed distance should all be closely regulated.