Accuracy in Analytical Method Validation is one of the most critical parameters, directly impacting the reliability and credibility of test results. It ensures that the method measures exactly what it is intended to, without bias or error. In this article, we will explore how to perform accuracy testing in analytical method validation, supported by step-by-step […]
Accuracy in Analytical Method Validation is one of the most critical parameters, directly impacting the reliability and credibility of test results. It ensures that the method measures exactly what it is intended to, without bias or error. In this article, we will explore how to perform accuracy testing in analytical method validation, supported by step-by-step calculations and real-world case studies. Whether you’re a beginner or an experienced analyst, this guide will help you enhance your understanding and confidently apply accuracy testing in both method development and validation processes.
where: m is slope, x is the concentration, c is the intercept and y is the area response
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A drug substance D having the following specifications for related substances:
Sample concentration is 1.0mg/ml.
Standard preparation for Accuracy calculation
Since sample concentration is mg/ml or 1000 mcg/ml. The concentration of Isomer I at
Use the above concentration to determine m (slope), c (intercept) and accuracy
| Concentration (mcg/ml) | Area response |
| 5 | 154570 |
| 7.5 | 231850 |
| 10 | 309160 |
| 12.5 | 386423 |
| 15 | 463710 |
| R2 | 1 |
| Slope (m) | 30914.12 |
| Intercept (c) | 1.4 |
For y = 154570, x will be ( 231850 – 1.4)/30914.12 =5.0 mcg/ml
For y = 154600, x will be ( 154600 – 1.4)/30914.12 =5.0 mcg/ml
For y = 154200, x will be ( 154200 – 1.4)/30914.12 = 4.9 mcg/ml
and
For y = 309160, x will be ( 309160 – 1.4)/30914.12 =10 mcg/ml
For y = 463710, x will be ( 463710 – 1.4)/30914.12 =15.11 mcg/ml and similarly x can be calculated for other y (area response as well
Calculate the accuracy at each concentration using the following formulae
Accuracy = (Calculated concentration/True concentration) x 100
| Concentration level | True concentration | Calculated concertation | Accuracy |
| 50% | 5.2 | 5.0 | 96.2% |
| 50% | 5.2 | 5.0 | 96.2 |
| 50% | 5.2 | 4.9 | 94.23 |
| Average | – | – | 95.54 |
| Average deviation | – | – | 102.04 |
Conclusion: Average deviation is less than 2.0% and hence method complies the accuracy test
Note: Similarly accuracy can also be calculated at 100% and 150% level
Accuracy is a key parameter in analytical method validation, requiring both technical knowledge and practical experience to perform effectively.
We hope this article has clarified your doubts and given you the confidence to independently carry out accuracy testing during method development and validation.
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References
Abbreviations
Accuracy is performed at 50%, 100% and 150% of the specification level. Standard solution is injected in triplicate at each level. Concentration is calculated using equation y = mx +c. Accuracy is calculated using formula: Accuracy = (calculated concentration/true concentration) x 100
Accuracy is performed for Active pharmaceutical ingredients or its stages. It is not applicable for dosages forms.
Disclaimer: The numerical data used in the tables or calculations are not actual data. It is designed to explain the topic.
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