Liu L X, Marziano I, Bentham A C, Litster J D, White E T, Howes T
Division of Chemical Engineering, The University of Queensland, Brisbane, Qld. 4072, Australia.
Int J Pharm. 2008 Oct 1;362(1-2):109-17. doi: 10.1016/j.ijpharm.2008.06.023. Epub 2008 Jul 4.
Powder flowability is one of the key parameters in the pharmaceutical tabletting process. The flowability is affected by both the particles' properties and the tabletting equipment characteristics. Although it is generally accepted that powder flowability increases with an increase in particle size, quantitative studies and comprehensive theoretical insights into the particle property effects are still lacking. In this paper, ibuprofen, a non-steroidal drug widely used as an anti-inflammatory analgesic was chosen as a model material to assess the effect of particle properties on its flowability. Ibuprofen typically has a needle shaped morphology. The flowability of ibuprofen size fractions was studied in detail using two flow measurement methods. The separated fractions were also compared to magnesium stearate lubricated ibuprofen and its size fractions. The experimental results showed that powder flowability is significantly affected by both the particle size and size distribution. The finest size fraction that is separated from the bulk ibuprofen powder flows better than the bulk powder. For powders with narrow size distributions, the flowability increases significantly with the increase in particle size. In addition, admixing magnesium stearate to ibuprofen not only increases the flow function of the powder, but also reduces the internal friction angle. A theoretical analysis based on the limiting tensile strength of the powder bed was carried out and the flow conditions for particles of different size and shape were developed.
粉末流动性是药物压片过程中的关键参数之一。流动性受颗粒性质和压片设备特性的影响。虽然一般认为粉末流动性随粒径增大而增加，但仍缺乏对颗粒性质影响的定量研究和全面理论见解。本文选择广泛用作抗炎镇痛药的非甾体药物布洛芬作为模型材料，以评估颗粒性质对其流动性的影响。布洛芬通常具有针状形态。使用两种流动测量方法详细研究了布洛芬不同粒径级分的流动性。还将分离出的级分与硬脂酸镁润滑的布洛芬及其粒径级分进行了比较。实验结果表明，粉末流动性受粒径和粒径分布的显著影响。从散装布洛芬粉末中分离出的最细粒径级分比散装粉末流动性更好。对于粒径分布窄的粉末，流动性随粒径增大而显著增加。此外，将硬脂酸镁与布洛芬混合不仅增加了粉末的流动函数，还减小了内摩擦角。基于粉末床极限抗拉强度进行了理论分析，并得出了不同尺寸和形状颗粒的流动条件。
