Uhumwangho M U, Okor R S
Department of Pharmaceutics, University of Benin, Benin City, Nigeria.
Int J Pharm. 2004 Oct 13;284(1-2):69-74. doi: 10.1016/j.ijpharm.2004.07.002.
The effect of varying the compression pressure on the brittle fracture tendency of alpha-cellulose and lactose tablets has been investigated. Tablet tensile strength, (T), packing fraction, (Pf), and brittle fracture index (BFI) were determined at different compression pressures (0.82, 1.22 and 1.63 MPa). In another aspect of the study, alpha-cellulose and tapioca powders were mixed in various proportions to obtain powders of varying plastoelasticity. Their tableting characteristics T, Pf and BFI were also determined at the different compression pressures. The polymer, alpha-cellulose displayed the characteristics of plastic compression--a low BFI but high T and Pf values while lactose displayed the characteristics of elastic compression--a high BFI but low T and Pf values. The degree of plastic compression decreased as the proportion of tapioca in the powder mixture increased from 0 to 50% w/w. Higher concentrations of tapioca >50% produced crumbly tablets at all compression pressures, thus indicating that tapioca is highly elastic. Increase in the compression pressure caused an increase in the BFI values of lactose tablets, 0.39-0.76 but a decrease in the BFI values of alpha-cellulose tablets, 0.38-0.09. This decrease became less pronounced as the plasticity of the powder mixtures decreased. The difference in the response of the tablets to the change in compression pressure relates to the difference in the plastoelasticity of the materials tested.
研究了改变压缩压力对α-纤维素和乳糖片剂脆碎倾向的影响。在不同压缩压力(0.82、1.22和1.63兆帕)下测定片剂的抗张强度(T)、堆密度(Pf)和脆碎指数(BFI)。在该研究的另一个方面,将α-纤维素和木薯粉按不同比例混合以获得具有不同塑弹性的粉末。还在不同压缩压力下测定了它们的压片特性T、Pf和BFI。聚合物α-纤维素表现出塑性压缩的特性——BFI值低但T和Pf值高,而乳糖表现出弹性压缩的特性——BFI值高但T和Pf值低。随着粉末混合物中木薯粉的比例从0增加到50%(w/w),塑性压缩程度降低。木薯粉浓度高于50%时,在所有压缩压力下都会产生易碎片剂,因此表明木薯粉具有高弹性。压缩压力增加导致乳糖片剂的BFI值从0.39增加到0.76,但α-纤维素片剂的BFI值从0.38降低到0.09。随着粉末混合物可塑性降低,这种降低变得不那么明显。片剂对压缩压力变化的响应差异与所测试材料的塑弹性差异有关。