Key Points
- Tablet coating must maintain the active pharmaceutical ingredient (API) stability and support bioavailability.
- A wide range of tablet defects can occur during manufacturing and coating, like chipping, cracking, sticking and picking, and capping.
- Scaling a new drug formulation from development to manufacturing means preventing scale up problems that lead to tablet defects.
- You can identify scale up problems by creating a compaction profile, using a rotary tablet press, and analyzing formulation and strain sensitivity.
Tablet Manufacturing Objectives
As a tablet manufacturer, it’s essential for you to produce uniform, high-quality tablets that:
- Mask undesirable tablet tastes and odors
- Protect the drug’s ingredients from contamination
- Prevent the drug from being dissolved in stomach acid
- Improve overall drug appearance
- Implement a delayed drug release
To manufacture tablets that meet these requirements, a variety of coating types like film and sugar are used. Tablet coating must maintain the active pharmaceutical ingredient (API) stability and support bioavailability, requiring an enteric coating or one that supports controlled or immediate release.
You must keep all of these factors in mind when manufacturing film-coated tablets while also keeping an eye out for tablet defects.
Types of Tablet Manufacturing Issues and Defects
There are many problems in tablet manufacturing. Below are just a few of the most common tablet manufacturing issues that can occur:
Cracking
Cracked tablets have film cracks or splits throughout the tablet batch. Typically, tablet cracking occurs when there are high internal stresses in the coating formulation. To prevent tablet cracking, use lower molecule weight polymers or blends and adjust the plasticizer type and concentration.
Capping
Capped tablets include the top of the tablet breaking off, causing it to separate. Although capping occurs during tablet manufacturing, it’s often not discovered until the coating process, resulting in broken tablet pieces or bumps reflected in the coating. The most effective solution to prevent capped tablets is to increase the dwell time or analyze your product’s formulation and production process.
Chipping
Chipping is when the film-coated tablet becomes dented or chipped, typically around the tablet’s edges. A common cause of tablet chipping is excessive attrition during the coating process. To mitigate tablet chipping due to the coating formulation, increase your film hardness by boosting the molecular grade of the polymer solution.
Sticking and Picking
Sticking and picking occur when the coating removes a piece of the tablet from the core. This common problem in tablet manufacturing can happen for several initial reasons, like poor tablet quality and over-wetting or under-drying the tablets. It’s crucial to understand the tablet’s profile and how the coating is applied to fix sticking and picking issues. Flat-faced tablets are at greater risk for sticking and picking, but you can prevent this defect by increasing the drum speed and ensuring the film coating dries rapidly.
Blistering
Blistering occurs when the film coating becomes detached from the substrate, forming a blister on the tablet. The most common cause of tablet blistering is overheating during the air spraying process at the end of a run. You can mitigate tablet blistering by selecting milder, more appropriate drying conditions for your film-coated tablets.
Flaking
Tablet flaking occurs when film coating flakes off, exposing the tablet surface. Flaking usually happens when an initial cracking issue isn’t resolved. To reduce flaking indefinitely, resolve any cracking problems by analyzing the internal stresses in the coating formulation. Then, adjust the spray rate with the drying temperature.
Scale-Up Problems Lead to Tablet Defects
Scaling a new drug formulation from development to manufacturing means preventing scale-up problems that lead to tablet defects. Problems in tablet manufacturing like capping and sticking and picking often aren’t noticed until it’s time for production.
How To Identify Scale-Up Problems
You can mitigate scale-up problems during development through a series of easy experiments and alternative solutions. That way, you can address potential obstacles to prevent tablet manufacturing issues from occurring.
Create a Compaction Profile
A compaction profile shows you how your tablet powder performs under compression. You can obtain a compaction profile of your powder formulation by testing it at different force levels to determine the tablet breaking strength.
Use a Rotary Tablet Press
Moving your manufacturing process to a large rotary tablet press equipped with 40 to 70 tooling stations improves your production speed, compaction process, and powder dynamics. Larger tablet presses are a common solution for scale-up problems.
Analyze Formulation Strain Rate Sensitivity
Wet granulation can develop adequate tablets at all turret speeds. However, strain rate–sensitive formulations require a slower turret to manufacture quality tablets. These tablet formulations are a common scale-up problem because they can’t manufacture as many tablets per hour as wet granulation formulations. Analyze your formulation’s strain rate sensitivity to determine the appropriate turret speed to use during manufacturing.
Ways To Improve Your Pharmaceutical Tablet Manufacturing Process
After you’ve conducted a few experiments and purchased adequate tablet compression equipment, here are a few ways to improve your pharmaceutical tablet manufacturing processes:
- Use extended head flats
- Adjust temperature inconsistencies
- Use pre-picking or tapering
- Choose the proper fill cam
Solving Problems in Tablet Manufacturing and Coating
There are a lot of factors to consider in the tablet manufacturing process. But with Thomas Processing as your tablet coating expert, you can leave the analysis up to us. Remembering and watching out for the dozens of problems in tablet manufacturing is a daunting task, but when you purchase a quality tablet coater from us, you get a partner who offers you ongoing support. Contact us today to learn more about how we can help you solve your tablet manufacturing and coating issues.
