Accuracy determines whether the product can be extracted using the solvent used in the test method.
- A complex sample matrix is a mixture of different components, such as drug substances, impurities, and excipients. The solvent used in the test method must be able to dissolve all of the components in the sample matrix in order to ensure accurate results.
- The known impurities should be extractable within a range of 90% to 110% for concentrations of 0.5% to 1.0%. If no known impurities are available, the drug substance can be used as an impurity and spiked onto a placebo.
- For impurities that are less than 0.5%, there is more error associated with the method, so an accuracy range of 80% to 120% is acceptable. For identification level or LOQ (limit of quantitation) levels, an accuracy range of 50% to 150% is acceptable.
- If the drug substance response is being used for known impurities, the response factor must be calculated using a linearity study before accuracy can be assessed. The accuracy study should pass using the response factor. However, this can be challenging if pure impurities are not available.
Assay:
In drug manufacturing, it is crucial to accurately determine the concentration of the active pharmaceutical ingredient in the finished product. For example, if a tablet is claimed to contain 100 mg of a specific drug, the validated analytical method should provide results close to this known value. If the measured concentration is consistently around 100 mg, the method is accurate, indicating that it can reliably assess the drug's potency in the final product.
Impurity Quantification:
Pharmaceutical products must meet strict quality standards, which often include limits on impurity levels. Method validation is necessary to accurately quantify impurities present in drug substances or drug products. For instance, if the method determines that an impurity level is 0.1% in a drug product, accurate results should consistently be around this value. An accurate method ensures compliance with regulatory requirements , product's safety and effectiveness.
Content Uniformity Testing:
Content uniformity testing is critical to ensure that each dosage unit (e.g., tablet or capsule) in a pharmaceutical batch contains an appropriate and consistent amount of the API. An accurate method will measure the API content in different dosage units and show that the majority of the units fall within the specified limits. This ensures that patients receive a consistent dose of the medication.
Dissolution Testing:
Dissolution testing is performed to assess how quickly a drug substance dissolves from a dosage form (e.g., a tablet) and becomes available for absorption. Accurate dissolution testing ensures that the drug product releases the active ingredient at the intended rate, which is crucial for its therapeutic effectiveness and bioavailability.
Read also: pH and pKa Concepts in Method Development by HPLC
Resource Person: Vadivelan Elangovan
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