Issue link: https://www.e-digitaleditions.com/i/1199406
Tablets & Capsules January 2020 15 although some formulations may have especially low melt- ing points and require a cooler temperature. Dry the compressed air. Even if the compressed air supply has a dryer positioned after the compressor, the air can pick up condensation traveling to the capsule filler from its source. This condensation can then find its way into segment bores at the machine's cleaning station and cause the formulation to stick. Installing an air dryer/ water separator on the incoming pressurized air supply directly at the capsule filler can eliminate this problem. Slow the machine. Decreasing the capsule filler's oper- ating speed can sometimes reduce the negative effects of a sticky formulation, as the machine will often do a better job of containing the powder in the appropriate areas. Verify slug formation and transfer. Proper slug for- mation is a key attribute of good capsule filling because it promotes weight control, reduces waste, and keeps the formulation within the correct areas of the tooling. If the machine doesn't form a proper slug, loose powder can migrate into undesired areas of the machine and coat the parts. A quality slug should hold its cylindrical form during transfer from the dosing disk into the capsule body, and once again maintain its form as the machine pushes the capsule body into the cap. Ensure proper transfer station alignment. During dosing, the transfer station is where the formulation moves from the bowl into the lower segment. The lower segment bores should align perfectly with the dosing faces, restricting the components' movement and leading to inconsistent capsule weights, capsule splits, non-sepa- ration, and even machine crashes. Manufacturers often hope for a silver-bullet approach— one single solution that will fix every sticky formulation issue—but the solution is rarely that simple. Several factors often combine to cause a material to stick, and the prob- lem is best solved using a systematic approach. Solutions to try first The following items are a good place to begin trouble- shooting when facing a sticky formulation for a capsule product. These are common contributors to sticking and can be fixed with minimal disruption to operations. Control the humidity. Many formulations have hygroscopic properties, meaning they will absorb mois- ture from their immediate environment. As the mois- ture level in a formulation increases, it becomes stickier. Operating in a lower humidity environment will reduce moisture in the formulation and the likelihood of material buildup on the tooling. A good range for many products is between 35 and 45 percent relative humidity. Also, keeping holding containers closed as much as possible will minimize the formulation's exposure to humidity in the environment. Control the temperature. You may be able to minimize stickiness by controlling the temperature in all production and storage areas. One manufacturer even found success by positioning a cold-air duct directly at the capsule fill- er's dosing station. The optimal temperature to minimize stickiness for most formulations is between 60° and 75°F, Photo 1: Sticky formulation caked onto the tooling surfaces can restrict the components' movement, causing inconsistent capsule weights, capsule splits, non-separation, and even machine crashes. Acid Resistant Vegetable Capsules ) u . u, ' . AN EXCELLENT CHOICE FOR DELIVERY OF ACID-SENSITIVE ACTIVE INGREDIENTS . <> . BioCaps Enterprises, Inc. www.biocaps.net • info@biocaps.net US Patent 9452141