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The problem of weight variation in filled two-piece cap- sules is like a sleeping giant. It's often tip-toed around for fear of upsetting it, and weight variation doesn't jump out at you like dented ends or split capsules do. As the need for content uniformity increases and regulations become more strict, manufacturers must ensure weights are within a lim- ited range from capsule to capsule throughout production. This article describes how to use "5M and 1P" root-cause analysis to identify the most common sources of weight variation and how to prevent them when filling capsules using a tamping-style automatic filler. The 5M and 1P method goes by different names, but the principles are the same. The five M's stand for machine, material, method, measure- ment, and Mother Nature. The P stands for people. The root cause of most quality problems can be assigned to one of these six areas. Identifying and addressing them is a sure- fire way to improve your operation. The process as designed In tamping-style capsule fillers, the objective is to create uniform powder slugs in a five-step process that uses a dos- ing bowl, product bed, tamping pins, and a dosing disc (Figure 2). Slug formation begins at tamping station one, where penetration of the pins into the dosing disc is the deepest of the five stations. Thereafter the penetration becomes shal- lower, in stair-step fashion, typically in increments of 2 to 3 millimeters. In this manner material, is added and the slug of compressed particles grows. At the end of the tamping process, these cohesive and uniform slugs are transferred cleanly into the open body of the capsules. The photos above show slugs that were exposed by pushing the capsule body up from the bottom of a segment. Note that the upper portion of the slug—which extends beyond the capsule body—maintains its form in the top photo. This is the desired result, a slug that allows the machine to close the capsule without disturbing the pow- der, thereby locking all the material into the finished cap- sule. The loose slugs shown below it will cause weight vari- ation and possibly split capsules. 10 January 2017 Tablets & Capsules Figure 1 "What is the most prevalent problem in your capsule filling process?" [1] Slugs that maintain their form (top) enable the capsule filler to close the capsule without disturbing the powder. Loose slugs like those in the bottom photo will lead to weight variation and other problems. 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% Figure 2 The tamping process (side view) Bowl Tamping pin Powder bed Disc Sealing plate Equipment failure Capsule defects Weight variation Low yields Formulating

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