by Martin Hack
Compliance with GMPs (good manufacturing practices) is paramount for nutraceutical manufacturers seeking to produce high-quality dietary supplements. This is especially true for companies struggling with batch-to-batch consistency and contamination during tablet manufacturing—two common challenges to GMP compliance.
By July 2010, all manufacturers developing dietary supplements and nutraceuticals for sale in the United States will need to comply with federal GMPs. While the cost of compliance is high—$38,000 to $61,000 a year by FDA estimates—tablet manufacturers can recoup that operational expense over the long term by investing in high-efficiency tablet coating equipment that will allow them to produce high-quality products with fewer defects, while actually increasing production speed.
The most advanced tablet coaters on the market are engineered with current GMPs in mind. From tablet pan design to spray technology, these machines have the ability to reduce processing times by up to 35 percent. By decreasing production times, manufacturers can operate with fewer tablet coaters, making it easier to meet GMP standards for this part of the manufacturing process.
Better Batch Consistency
The biggest limitation of traditional tablet coaters is the uniformity they can achieve. Tablet consistency is a large factor in quality control and time to market for tablet-based supplements. Typically, for a cosmetic coating, manufacturers can get uniform tablets, but inefficiently. More time and coating solution are required, increasing the operational costs of the manufacturing process.
For example, with conventional coaters, tablet weight must increase 4 percent to 5 percent to achieve a uniform coat. But the newest cosmetic coaters achieve the same coverage with only 1.5- to 2-percent weight gain. Additionally, advanced tablet coating technology can achieve a 4-percent coefficient of variation, which is better than any traditional machine.
High uniformity is also achieved through another technical advantage of new coaters, the mixing system. To get high uniformity, tablets must be adequately mixed. The most advanced system uses spiral baffles to move tablets constantly through the coating pan. One of the baffles moves tablets to the back of the pan, while the other brings them forward. In 10 minutes or less, manufacturers can attain tablet homogeneity in each batch.
The New Shape of Tablet Pans
The tablet pan may seem like a basic component of a coater, but its role in increasing the efficiency of nutraceutical campaigns is important. Different sizes and shapes of the pan can affect the number of defects in a batch.
Traditional tablet pans are short in length and large in diameter. This creates a thick tablet bed when solids are put in the coater. However, a zone exists in the middle of the tablet bed that is slow-moving, and tablets in that area do not get exposed to the surface of the bed as often. That means the process takes longer and uses more coating solution.
High-efficiency coaters have coating pans that are longer in length, but smaller in diameter. Because the tablet bed is spread wider, there is no slow-moving zone. The tablets are in constant motion, so they enter the spray zone more often for higher efficiency and better uniformity.
The smaller diameter pan also helps prevent twinning, which is when tablets stick together in the tablet bed. These tablets must be sorted out, and often are counted as rejects, affecting overall batch efficiency. When the tablet bed is thinner in the narrow pan, the tablets stay in motion, thus preventing twinning. This is especially valuable to manufacturers creating supplements as elongated or flat tablets, which are more likely to stick together than round tablets.
