Precise deposition of complex particles for structured functional products

在制药工业中，涂料在生产和产品开发中占有非常重要的地位。固体剂型，如片剂、颗粒、颗粒等，通常被包裹，以控制药物在体内的释放，并防止水分或磨损等外部因素。这通常是通过细粉末的干燥涂层来实现的，因为这减少了环境问题（不排放挥发性有机溶剂）和更低的能耗（不需要后续的干燥或蒸发操作）。但是，干涂工艺在使用涂层粉末和能源投入方面是浪费的，因为当涂层均匀性不符合要求时，整批处理。为了减轻这种情况，通常使用过量的涂层粉末，并使用过量的能量输入，以确保所有固体都得到充分的涂层。我们的目标是通过确定给定的基材和粉末涂层组合来解决这些问题：(i)单个粉末层的涂层如何受到颗粒特性的影响？（ii）搅拌器应如何操作以在整个批次中提供均匀的涂层？（三）保证产品涂覆均匀的最小能量输入是多少？在这项研究中，我们将通过控制和操纵颗粒物理（尺寸、形状）和表面（粗糙度、界面能）特性的分布，并表征所得到的涂层质量，来确定如何在基本的颗粒水平上实现涂层。涂层粉末通常是非常细和有凝聚力的，因此很容易凝聚形成大簇。工业粉末涂料要求这些涂料粉末团块被一致地分解成单个颗粒，并精确地输送到宿主。我们将确定如何定制该过程，以增强系统实现任何粉末的能力。通过确定粉末涂料的基本原理，以及材料特性和工艺参数的影响，我们将创建一个干粉涂料的制度图，这将使行业调整涂料操作，以最大限度地减少粉末和能源的使用。

In the pharmaceutical industry, coatings have a very important place in manufacturing and product development. Solid dosage forms like tablets, pellets, granules etc. are typically coated in order to control the drug release within the body, and also to protect against external factors like moisture or attrition. This is often achieved through dry coating with fine powders, since this provides reduced environmental concerns (no volatile organic solvents emitted) and lower energy consumption (no subsequent drying or evaporation operations required). However, the dry coating process is wasteful in terms of coating powder used and energy input, since when the coating uniformity does not meet the requirement, the entire batch is disposed of. To mitigate this, an excess of coating powder is often used, with excessive energy input to ensure all solids are sufficiently coated. We aim to address these problems by determining for a given combination of substrates and powder coatings: (i) How is coating of a single powder layer influenced by particle properties? (ii) How should a mixer operate to provide uniform coating across the entire batch? (iii) What is the minimum energy input to ensure uniform product coating?In this research we will determine how coating is achieved on the fundamental, particle level, by controlling and manipulating the distribution of particle physical (size, shape) and surface (roughness, interface energy) properties and characterising the resulting coating quality. Coating powders are typically extremely fine and cohesive, and hence are prone to agglomerating to form large clusters. Industrial powder coating requires these coating powder agglomerates to be consistently broken down to single particles and precisely delivered to the host. We will establish how the process can be tailored to enhance the ability of the system to achieve this for any powder. By determining the underlying principles of powder coating, and the influences of material properties and process parameters, we will create a regime map for dry powder coating, which will enable industry to tune coating operations to minimise powder and energy use.