 |
The United States Pharmacopeia (USP) General Chapters <41> "Balances" and <1251> "Weighing on an Analytical Balance" aim to ensure weighing accuracy and eliminate unnecessary over-testing for US pharmaceutical manufacturers and suppliers. Chapter <41> focuses on accuracy and balance assessment, whilst <1251> suggests that the type and frequency of balance checks should be determined by the risk and process tolerance of the application.
If companies are still carrying out the former widespread practice of checking balances daily or even before every use, they could potentially benefit from an optimized risk-based testing schedule which could eliminate unnecessary testing and bring about significant time, costs and material savings.
Chapter <41> specifies that a test weight of between 5 and 100% of the balance capacity must be used when testing a balance for accuracy. Testing below 5% is not allowed. In contrast, repeatability testing and minimum weight determination should be carried out using a small weight below 5% of the balance capacity. The minimum weight of a balance is unique to each individual balance and refers to the smallest sample size that can be weighed accurately. Crucially, weighing net samples sufficiently above the minimum weight is recommended in order to take balance fluctuations into account. The use of a safety factor ensures that weighing always take place in the safe weighing range of the balance for a given application.
Learn more about how you can benefit from an optimized balance testing schedule.
METTLER TOLEDO's Excellence Level analytical balances have built-in functionalities to ensure that weighing is always in the safe weighing range of the balance. CarePac® weight sets contain only two weights – which is all that is required for routine balance testing between calibrations. With just two weights, significant savings on purchasing and recalibration costs can be made.
USP Chapter <1251> suggests that the type and frequency of balance checks should be determined by the risk and process tolerance of the application. METTLER TOLEDO's Accuracy Calibration Certificate (ACC) allows balances and scales to be calibrated according to a company's individual weighing process tolerances and ensures that local and global regulations are adhered to. By following the guidance in the ACC, companies stand to benefit from improved quality, and reduced waste and rework. Learn more about ACC.
For all applications, weighing should be carried out using a calibrated balance that meets the requirements for repeatability and accuracy. The scientific principles are summarized in METTLER TOLEDO's Good Weighing Practice™ (GWP®)
Learn more about how you can benefit from an optimized balance testing schedule.
