A Method Comparing the Dividing and Packing Accuracy of Powder Dividing Machines with a Twin Rotary-disk

Abstract

A method for comparing the dividing and packing accuracy of four powder dividing machines;(A), (B), (C) and (D), were devised. The working time defined as the time from the start of dividing to the end of packing the powders was measured. Ten % phenytoin powder (10% Aleviatin^® powder, repose angle: 41°, 50% particle size: 123 pm), magnemagnesium oxide (repose angle: 31°, 50% particle size: 320 μm), pancreatin powder (repose angle: 40°, 50% particle size: 75 pm), and 50% aspirin granule (Minimax^®, repose angle: 41°, 50 % particle size: 250μm) were all used for the test. The maximum division errors were found to be significantly related to the coefficients of variation (CV) of packed powder's weights. This indicated that the CV values of the packed powder below 5 % represented the maximum devision errors below 10 %. We next compared the performance of the powder dividing machines by evaluating the working time to achieve a CV value of below 5 %. For dividing and packing the phenytoin powder, (A), (B), and (C) had an equal ability, however, (D) was somewhat inferior. In the case of magnesium oxide, (A) showed the best dividing performance of the four machines. In the case of pancreatin powder, (A), (C), and (D) had a excellent dividing performance. For the 50 % aspirin granules, all machines achieved a fast and accurate division, and the difference between the machines was small. These results thus indicate that this newly developed method for comparing dividing machines appears to be useful.