Accuracy of dividing weight of 11 drugs (5 powders, 3 fine glanules and 3 glanules) were tested on a automatic pre-packing machine, TOSHO BL-4W. The mean coefficient of variation (C. V.) was 3.9% for 30 subpacks of 1g in theoretical weight and sufficient accuracy of dividing weight was obtained. However, fine lactose, corn starch, and precipitated calcium carbonate showed relatively large C. V. values. The mean C. V. of 3 drugs (Gastropylore, heavy magnesium oxide and Marzulene S) were 3.0 and 5.5% obtained on 0.3 and 0.6g in theoretical weight, respectively, and these mean C.V. were regarded as sufficient. However, on 0.3g in theoretical weight, Gastropylore gave relatively large C. V., 8.5%. Gastropylore also gave relatively large C. V. on total weight of 30 subpacks. Angles of fall were highly correlated to C. V. values. It is suggested that angles of fall are especially useful for predict accuracy of dividing weight on a pre-packing machine.
