Issue link: https://www.e-digitaleditions.com/i/1371139
Tablets & Capsules May/June 2021 27 Compaction analysis data facilitates a Quality-by-De- sign (QbD) approach to formulation development. By studying lubrication and compaction behavior in this way, it is possible to see the effect of formulation and process changes on tablet properties. This includes understanding the impact of parameters such as blend- ing time, moisture content, or lubricant concentration. These will be very familiar to formulation developers, as understanding their impact is essential to implementing QbD in the development process. Assessing the compaction and lubrication properties of tablets in the laboratory has recently become possible using advanced powder compaction analysis instruments. Using state-of-the-art measurement and data-handling techniques, these instruments assess compaction and lubrication behavior through the measurement of tablet compaction, ejection, and detachment forces under con- trolled conditions. Previously, these measurements have required expensive and complex compaction simulators. These simple laboratory systems can accurately eval- uate a large number of formulation and process options in a short time. Sample testing for a single formulation can be completed in as little as 15 minutes with less than 2 grams of material, and available software automatically carries out calculations and generates easy-to-interpret plots. The software displays the sample results with com- parison to industry standard critical quality attributes. Data generated includes the USP <1062> characteristics (tabletability, compressibility, and compactibility), lubri- cation behavior, and tablet elastic recovery. The following paragraphs describe the data summa- rized by the compaction triangle, how it is generated, and what the results mean for a formulation. The same information and discussion are also provided for lubrica- will give you the desired result? In other words, how can you avoid putting garbage in? The powder properties that have the greatest impact on tablet manufacture and quality are those relating to compaction and lubrication. Of course, adequate flow and the uniform distribution of the active pharmaceutical ingredient (API) within the powder are also required, but these are generally easier to achieve. In this article, we'll delve into how to assess a powder's compaction and lubri- cation properties in order to make better tablets. The major issue holding back proper understanding of powder tableting has been the difficulty of studying com- paction and lubrication behavior on a laboratory scale under controlled conditions. The key requirement for a "fair test" with which to assess powder properties has been missing. To address this issue, USP <1062> included the compaction triangle, as shown in Figure 1. The com- paction triangle describes three relationships that can be used to evaluate a material's compaction properties: tabletability, compressibility, and compactibility. Com- paction triangle data characterizes a material's intrinsic compaction behavior. For this reason, the calculations involved always take into account the tablet size and shape, so the tablet dimensions used to generate the data need not match those of the tablets being manufactured in full-scale production. The compaction triangle characterizes compaction behavior, but USP <1062> does not cover how to evalu- ate blend lubrication. This can be achieved by measuring the forces required to remove the tablet from the die after compaction—the ejection and detachment forces. This data can forewarn the user if their formulation has a pro- pensity for sticking and picking. Figure 1 Compaction triangle as described in USP <1062> Tensile strength Solid fraction Compression pressure Compactibility Tabletability Compressibility Account for tablet dimensions Breaking force Manufacturability Compression force Account for tablet dimensions