Issue link: https://www.e-digitaleditions.com/i/238663
f-Schulmanart_26-29_Masters 12/30/13 2:06 PM Page 29 Tablets & Capsules January 2014 29 Table 2 Possible implications of overly soft and hard granules Soft Hard Soft, friable tablets Picking and sticking at the tablet press Low tablet weights High ejection forces Excess fines, leading to API segregation and poor flow Excessive abrasive wear of punches and dies And yes, despite what you may have heard, it is indeed possible to include colors. You may have to extend the color on a fine excipient (i.e., starch), but I've succeeded in making yellow, pink, orange, blue, and green tablets from dry-granulated formulas. I simply added a pre-milled dye-starch mixture. None of the tablets was mottled or spotty from adding the dry dyes. (I prefer lakes.) Selecting a roll compactor Experience has led me to prefer certain types of roller compactors over others, but test the different machines for yourself. You'll soon learn which setup is best for your product(s) and processes. Each design has its pros and cons, but look for equipment with these features: • Rollers that remove rapidly, enabling you to change and clean them quickly; • A PLC that adjusts the operation to ensure consistent powder flow and compacts of consistent density; • A variable-speed milling-screening device, preferably with a PLC, that is either integral to the compactor or within close proximity; and • Seals that keep the powder in the nip area. Evaluate the designs, which differ from manufacturer to manufacturer. They will also differ according to the type of rollers you select: die-and-punch (DP) rollers or flat rollers. With DP rollers, one roller nests within the raised walls of its counterpart. See Figure 3 and the photo on page 28, which shows the seal used on a Freund-Vector roller compactor equipped with DP rollers. Conclusion In my experience, changing from wet granulation— which entails the possibility of water degradation—was met favorably by regulatory authorities for immediate-release products. In the dietary-supplement industry, anyone with compression problems should investigate roller compaction. It certainly suits herbal products better than wet granulation, which degrades them and unleashes unpleasant odors. T&C Vic Shulman is president of Darvic Consulting, Thornhill, Ontario, Canada. Tel. 905 731 9396. E-mail: darvic@rogers.com. Shulman has been training operators in basic manufacturing principles since 1992. He acquired his knowledge of roller compactors the old-fashioned way: By running and cleaning the equipment.