Related Experiment Video
Updated: Jul 14, 2026
10:22
Split Point Analysis and Uncertainty Quantification of Thermal-Optical Organic/Elemental Carbon Measurements
Published on: September 7, 2019
Uncertainty of measurement and error in stability studies
1Beckman Coulter Inc., 11800 SW 147 Avenue, Miami, FL 33196-2500, USA.
Journal of Pharmaceutical and Biomedical Analysis
|June 26, 2007
Summary
Shelf life determination relies on stability testing confidence intervals. Predictions have inherent error influenced by product specifics, measurement uncertainty, and experimental design choices.
Area of Science:
- Pharmaceutical Sciences
- Analytical Chemistry
- Statistics
Background:
- Shelf life estimation is critical for drug product stability.
- Regulatory requirements mandate using the lower confidence interval limit for shelf life determination.
- Predicting shelf life accurately involves understanding various sources of error.
Purpose of the Study:
- To analyze the factors influencing shelf life prediction error.
- To provide insights into optimizing experimental designs for accurate shelf life determination.
- To highlight the interplay between measurement uncertainty and experimental design in shelf life studies.
Main Methods:
- Utilized simulations to estimate the error in 1-year shelf life predictions.
- Analyzed the impact of degradation rate, number of time points, and design (full vs. reduced) on shelf life error.
- Investigated the correlation between measurement uncertainty (lot variability, method precision) and prediction error.
Main Results:
- A 1-year shelf life prediction can have an error of approximately 1 month, though this is product-specific.
- Factors like degradation rate and experimental design significantly affect shelf life prediction error.
- Increased number of lots and replicates in stability tests can reduce random variability and error.
Conclusions:
- Shelf life accuracy is contingent upon minimizing both measurement uncertainty and experimental design flaws.
- Optimizing the number of lots and replicates requires balancing measurement uncertainty with practical constraints.
- Robust experimental design and precise analytical methods are essential for reliable shelf life determination.
More Related Videos
Related Concept Videos
03:37Uncertainty in Measurement: Accuracy and Precision
Scientists typically make repeated measurements of a quantity to ensure the quality of their findings and to evaluate both the precision and the accuracy of their results. Measurements are said to be precise if they yield very similar results when repeated in the same manner. A measurement is considered accurate if it yields a result that is very close to the true or the accepted value. Precise values agree with each other; accurate values agree with a true value.
00:59Uncertainty: Overview
In analytical chemistry, we often perform repetitive measurements to detect and minimize inaccuracies caused by both determinate and indeterminate errors. Despite the cares we take, the presence of random errors means that repeated measurements almost never have exactly the same magnitude. The collective difference between these measurements - observed values - and the estimated or expected value is called uncertainty. Uncertainty is conventionally written after the estimated or expected value.
01:20Random and Systematic Errors
Scientists always try their best to record measurements with the utmost accuracy and precision. However, sometimes errors do occur. These errors can be random or systematic. Random errors are observed due to the inconsistency or fluctuation in the measurement process, or variations in the quantity itself that is being measured. Such errors fluctuate from being greater than or less than the true value in repeated measurements. Consider a scientist measuring the length of an earthworm using a...
01:20Random and Systematic Errors
Scientists always try their best to record measurements with the utmost accuracy and precision. However, sometimes errors do occur. These errors can be random or systematic. Random errors are observed due to the inconsistency or fluctuation in the measurement process, or variations in the quantity itself that is being measured. Such errors fluctuate from being greater than or less than the true value in repeated measurements. Consider a scientist measuring the length of an earthworm using a...
01:10Propagation of Uncertainty from Systematic Error
The atomic mass of an element varies due to the relative ratio of its isotopes. A sample's relative proportion of oxygen isotopes influences its average atomic mass. For instance, if we were to measure the atomic mass of oxygen from a sample, the mass would be a weighted average of the isotopic masses of oxygen in that sample. Since a single sample is not likely to perfectly reflect the true atomic mass of oxygen for all the molecules of oxygen on Earth, the mass we obtain from this particular...
02:46Uncertainty in Measurement: Reading Instruments
Counting is the type of measurement that is free from uncertainty, provided the number of objects being counted does not change during the process. Such measurements result in exact numbers. By counting the eggs in a carton, for instance, one can determine exactly how many eggs are there in the carton. Similarly, the numbers of defined quantities are also exact. For example, 1 foot is exactly 12 inches, 1 inch is exactly 2.54 centimeters, and 1 gram is exactly 0.001 kilograms. Quantities...