Summary of Verification Issues for Inspection Methods

1、 Basic content of testing method validation

The basic content of testing method validation includes drafting and approving the plan, and confirming the testing instruments.

Applicability verification (including accuracy testing, precision measurement, linear range testing, specificity testing, etc.) and result evaluation and approval.

2、 Basic steps for verifying inspection methods

The first step is to develop a validation plan, followed by confirmation of large precision instruments. The most crucial step is to conduct suitability testing of the testing method, and finally evaluate and approve the testing method.

1. Development of verification plan

The validation plan for inspection methods is usually proposed by the quality validation team. Based on the process conditions, chemical structure of raw materials, intermediates, and decomposition products of the product, relevant information is consulted to propose specification standards, determine inspection items, and specify impurity limits, which is the draft quality standard.

Determine the scope of inspection and testing based on the draft quality standards, develop specific operational steps for the inspection methods, and finally obtain approval from relevant personnel before implementation.

2. Confirmation of large precision instruments

The detection instruments used in analysis and testing can generally be divided into three categories:

A. Common instruments: disintegrator, refractometer, analytical balance, acidity meter, solubility tester, conductivity meter, etc

B. More precise instruments: polarimeter, permanent stop titrator, Fisher's moisture meter, automatic titrator, drug dissolution meter, visible spectrophotometer, electrophoresis instrument, etc;

C. Large precision instruments: UV spectrophotometer, infrared spectrophotometer, gas chromatograph, high-performance liquid chromatograph, thin-layer scanner, etc.

To ensure the accuracy and reliability of analysis and testing data, each testing instrument should be confirmed before being put into formal use.

The confirmation of testing instruments is the basis for the validation of testing methods and should be completed before other validation tests begin.

The confirmation of testing instruments should be based on the type of instrument. Depending on technical performance, it usually includes installation confirmation, calibration, suitability pre testing, and reconfirmation.

3. Correction

Calibration is an important step in instrument confirmation and validation of testing methods, and should be carried out before the validation test. The calibration of ultraviolet spectrophotometer includes wavelength calibration, absorbance testing, accuracy testing, and stray light inspection.

Both gas chromatographs and high-performance liquid chromatographs require system suitability testing. Measure the minimum theoretical number of plates in the chromatographic column under specified chromatographic conditions. Separation degree and tailing factor, and the coefficient of variation should not exceed 2%.

The measuring instruments used in chemical testing, including volumetric flasks, pipettes, burettes, and analytical balances, should also be calibrated.

4. Applicability pre-test

After the installation confirmation of the instrument is completed, if its functional test meets the requirements, standard or reference materials should be used to check its applicability to confirm whether the instrument meets the usage requirements.

For example, the applicability pre test of the melting point tester is to use metronidazole with a known melting point for testing