Tablet compression is both an art and a science. The perfect tablet is the result of a precise balance of formulation, tooling, and machine parameters. When defects arise, they disrupt production schedules, increase waste, compromise compliance, and threaten patient safety. Let’s walk through some common issues we see in the tablet-making process and the troubleshooting tips you can use to address them effectively.
Capping and Lamination
Capping and lamination are two of the most persistent headaches in solid dosage manufacturing. These defects usually stem from air entrapment or excessive fines in your granulation.
If you observe the top of the tablet separating, check your pre-compression force. Increasing pre-compression allows more time for air to escape the die cavity before the main compression event. Additionally, verify your punch penetration depth; deeper penetration might help expel trapped air more efficiently.
If fines are the culprit, optimizing your granulation process to reduce the percentage of fines, adjusting the binder concentration, or slowing down the turret speed to increase dwell time are viable solutions.
Sticking and Picking
Sticking occurs when granulation adheres to the punch face, while picking happens when material gets stuck in the embossing or debossing. These issues frequently point to moisture problems or insufficient lubrication.
First, examine the moisture content of your granules. If the material is too wet, drying it further may resolve the issue. Conversely, if the formulation is too dry, static electricity might be causing the adherence.
If moisture content doesn’t appear to be the issue, inspect your punch tips for wear or scratches, as damaged tooling exacerbates sticking. Polishing the punch faces or applying a chrome coating can improve release characteristics.
Another potential solution is increasing the level of lubricant, such as magnesium stearate, or increasing the blending time to improve the mix’s anti-adherent properties.
Tablet Weight Variation
Consistent weight is critical for dosage uniformity. Variations here typically indicate flow issues within the feed frame or hopper.
Therefore, another troubleshooting tip for tablet-making is to inspect the flow of granulation from the hopper into the die. Ideally, the powder should flow freely and consistently. If you detect bridging or rat-holing, installing a force feeder or modifying the paddle speed can improve die filling.
Moreover, check the scraper blade for wear. A worn blade might not level the die correctly, causing inconsistent fill volumes.
Internal Machine Problems
The issue might be within the inner workings of your production equipment (namely, your pill presses). Perhaps a bearing got loose, or some tubing developed a leak. If you can’t pinpoint the problem in your tablet mix or external equipment, then hire a technician to examine your machinery.
This shouldn’t be done only once a complication arises. Preventative maintenance is your first line of defense against production downtime, so have someone regularly inspect your press. They can do things like check hydraulic and pneumatic lines for leaks or pressure drops, then use either ORFS or JIC fittings to reestablish a secure, leak-free seal under high pressure. They can also keep your turret and cam tracks clean to prevent the buildup of abrasive dust that accelerates wear on your tooling.
