Comparing different methods of measuring particle size for pharmaceutical excipients

Abstract: In pharmaceutical science, particle size is one of the most fundamental parameters of materials, but different particle-sizing analysis methods lack a uniform standard for measuring irregular particle size, making it difficult to compare the accuracy and applicability of different particle-sizing analysis methods. Experiments on excipients used in pharmaceuticals are carried out in this paper by laser diffraction analysis (Malvern wet and dry), dynamic image analysis (Qicpic), and microscopic methods (Qicpic, SEM, and light microscopy) to determine the applicability and limitations of each method, as well as to clarify their advantages and disadvantages. On the one hand, the shape of the excipients is determined using the 2D and 3D images acquired from Qicpic and SEM; sphericity, aspect ratio, D50, and D90 are employed as indicators to assess the accuracy and adaptability of Qicpic and Malvern analyses based on different testing principles. On the other hand, D10, D50, D90, percentage of fine particles, weighted residues are used in the Malvern methods to evaluate the difference between Malvern dry and wet applied to pure excipients and blend powders, as well as their stability with particle size distribution curves. Furthermore, while doing a wet analysis on lactose carriers, the effect of ultrasonication speed on particle size distribution and the accuracy of the Malvern wet analysis using the Fraunhofer or Mie theories, need to be considered. In addition, light microscopy was used to examine particle behavior during sonication. Finally, the particle size analysis methods are categorized for different sizes of particles and different shapes of particles.