Validasi Metode Part 2 - Selektifitas / Spesifisitas

Summary

This video discusses the importance of selectivity and specificity in method validation, particularly in the context of pharmaceutical analysis. It explores the differences between these two concepts, with selectivity referring to the ability to distinguish between different substances, while specificity ensures that the method identifies only the target compound without interference from others. The script highlights practical methods for evaluating both, including the use of chromatography techniques like HPLC, and emphasizes the role of validation in ensuring accurate and reliable results in pharmaceutical testing. The video also touches on how to handle interfering substances and the importance of proper sample preparation.

Takeaways

• 😀 Selectivity and specificity are key concepts in analytical method validation, but there is confusion around their definitions. Different sources use different terminologies.
• 😀 Selectivity refers to the ability to differentiate between the analyte and other substances in a sample. It ensures that the method can distinguish between different compounds.
• 😀 Specificity, on the other hand, refers to the ability of a method to identify a single, pure analyte without interference from other substances or degradation products.
• 😀 In the context of HPLC, selectivity is demonstrated when the system can separate different compounds based on their distinct physical-chemical properties.
• 😀 A method is considered selective if it can resolve individual peaks for each compound, without overlap, ensuring that each compound can be individually detected.
• 😀 For validation, specificity is verified by ensuring that the analyte's peak is free from interference or contamination from other substances.
• 😀 To evaluate selectivity, tests such as injecting placebo samples or matrices without analytes are performed to check for interference from solvents or degradation products.
• 😀 The resolution (greater than 1.5) between peaks in chromatographic methods like HPLC is a key criterion for determining if a method is selective.
• 😀 Specificity involves confirming that the identified peak is singular and pure, free from other overlapping peaks or compounds that may have similar retention times.
• 😀 Spectral analysis (such as UV-Vis spectra) is used to confirm the purity of the analyte peak, ensuring there are no hidden peaks at the same retention time, which would indicate contamination.

Q & A

What is the main topic discussed in the transcript?

The main topic discussed in the transcript is the concept of selectivity and specificity in the validation of analytical methods.

What is the difference between selectivity and specificity in analytical methods?

Selectivity refers to the ability of an analytical method to distinguish between different substances, including analytes, derivatives, degradation products, and interferences. Specificity refers to the ability of a method to identify a single, pure analyte without interference from other compounds, ensuring that the peak corresponds solely to the analyte in question.

Why are selectivity and specificity terms not harmonized globally?

Selectivity and specificity are not harmonized because different organizations use different terminology. For example, 'selectivity' is used by AYUB, while the International Conference on Harmonization (ICH) uses 'specificity'. This has led to confusion and inconsistency in the use of these terms.

How can selectivity be determined in an analytical method?

Selectivity can be determined by testing if the method can distinguish between the analyte and other substances, such as solvents, degradation products, metabolites, or other interferences, ensuring no overlap in retention times in chromatography.

What is a typical criterion for determining whether a method is selective?

A method is considered selective if the resolution between peaks of different compounds is greater than or equal to 1.5. This means the peaks must be well-separated with no overlap.

What does the resolution between peaks indicate in the context of selectivity?

The resolution between peaks indicates how well two compounds are separated in the chromatographic method. A resolution greater than or equal to 1.5 means that the peaks are sufficiently separated and not overlapping, indicating a selective method.

What role does the sample matrix play in testing selectivity?

The sample matrix plays a significant role in testing selectivity. If the sample matrix or solvents interfere with the response of the analyte, it may indicate that the method is not selective. The matrix must not cause significant interference in the detection of the analyte.

How is specificity different from selectivity in practical analysis?

Specificity focuses on the ability of the method to identify a pure analyte, without overlap with other compounds. In contrast, selectivity emphasizes the method's ability to distinguish the analyte from other potential interfering substances, such as metabolites or impurities.

What are the typical steps involved in testing for specificity?

Testing for specificity involves injecting a sample of the analyte and comparing the chromatographic peak with that of a pure reference standard. It may also involve using techniques like spectra comparison to confirm the purity of the analyte.

How does a chromatogram help determine whether a method is specific?

A chromatogram helps determine specificity by showing whether the peak corresponding to the analyte is pure, i.e., not overlapping with other peaks from contaminants, degradation products, or other substances in the sample. If the analyte peak is distinct and does not coincide with any other peaks, the method is considered specific.