When it comes to weighing and dispensing material in pharmaceutical industries, the precision and accuracy of the measurements are crucial as the required quantity of materials is calculated proportionally in the formulas. The scale sensibility and its calibration, among other factors, can introduce errors during the measurement.
Errors are not entirely avoidable because they are intrinsically associated with the weighing process – whether due to operator-dependent procedure or to the technological limitation of the instruments – but there is a mathematical way to reduce them during weighing.
How? With the weighing-by-difference method.
The term “weighing by difference” refers to the fact that the target weight of the material is the difference between two weights of the container: the weight of the container before and the weight of the container after you transfer the material from the container to the vessel.
If you weigh by difference, you avoid three errors:
For these reasons, weighing by difference is one of the most accurate methods for weighing liquid components and solutions. In addition, it is an efficient and clean technique.
To properly weigh your substance by difference, here are the steps you should follow:
The target quantity is obtained with the following calculation: W3 = W1 – W2.
The AXP365 Weighing & Dispensing™ module allows you to choose the weighing-by-difference method and set the appropriate parameters (e.g., tolerance range, scale precision) to perform your weighing operations in the most efficient, clean, and accurate way.
To learn more about AX for Pharma 365™ and how it helps pharmaceutical companies reduce errors and improve accuracy, contact us today.