Good laboratory practice

As per GLP guideline (L1) residual samples should be stored for one year after release.

Is it applicable to only formulation? or API also? Can you suggest?

According to Schedule “M” (GMP) requirements of the Indian Drug & Cosmetics Act 1940 and Rules thereunder 1945, please note the following,


  1. Quality Control System. -
    16.7 Reference/retained samples from each batch of the products manufactured shall be maintained in quantity which is at least twice the quantity of the drug required to conduct all the tests, except sterility and pyrogen/Bacterial Endotoxin Test performed on the active material and the product manufactured. The retained product shall be kept in its final pack or simulated pack for a period of three months after the date of expiry.

  2. Reference Samples:-
    23.1 Each lot of every active ingredient, in a quantity sufficient to carry out all the tests, except sterility and pyrogens/Bacterial Endotoxin Test, shall be retained for a period of 3 months after the date of expiry of the last batch produced from that active ingredient.

23.2. Samples of finished formulations shall be stored in the same or simulated containers in which the drug has been actually marketed.

Therefore, pharmaceutical manufacturer should retain reserve / control samples of both Final products as well as APIs (raw materials) according to Schedule “L-1” and Schedule “M” as above.

Thanks for your quick response, we should keep retain /reserve/control sample for every batches.

I am asking about the requirements of 'Residual samples"

The meaning of “Residual sample” is the same as “Control / Reserve sample” .
This means the remaining sample (initially collected as “Control / Reserve sample”) after analysis should be stored properly for specified storage period.

Note:- Internationally, the principles of “Good Laboratory Practice” (GLP) define a set of rules and criteria for a Quality system concerned with the organisational process and the conditions under which non-clinical health (Animal based Toxicological studies) and environmental safety studies are planned, performed, monitored, recorded, reported and archived. Therefore, the term “GLP” is used with reference to (animal based) non-clinical toxicological studies of chemical substances including drugs.


Sir please tell me analytical method validation and your telling every topic excellent sir

Sunilrbudhkar you are very excellent sir

The objective of validation of an analytical procedure is to demonstrate that it is suitable for its intended purpose.
The validation of analytical procedures is performed to the four most common types of analytical procedures:

  • Identification tests;
  • Quantitative tests for impurities’ content;
  • Limit tests for the control of impurities;
  • Quantitative tests of the active ingredient in samples of drug substance (API) or drug
    product or other selected component(s) in the drug product.

A brief description of the types of tests considered for Analytical method validation is provided

  • Identification tests are intended to ensure the identity of an analyte in a
    sample. This is normally achieved by comparison of a property of the sample
    (e.g., spectrum, chromatographic behavior, chemical reactivity, etc) to that of
    a reference standard;)
    Testing for impurities can be either a quantitative test or a limit test for the impurity in a sample. Either test is intended to accurately reflect the purity characteristics of the sample. Different validation characteristics are required for a quantitative test than for a limit test;
  • Assay procedures are intended to measure the analyte (drug) present in a given
    For the drug product, similar validation characteristics also apply when assaying for the
    active or other selected component(s). The same validation characteristics may also apply to assays associated with other analytical procedures (e.g., dissolution).

Furthermore revalidation may be necessary in the following circumstances:

  • changes in the synthesis of the drug substance (API);
  • changes in the composition of the finished product;
  • changes in the analytical procedure.
    The degree of revalidation required depends on the nature of the changes.
    Certain other changes may require validation as well.

Typical Analytical method validation characteristics which should be considered are listed below:

  • Accuracy
  • Precision
  • Repeatability
  • Intermediate Precision
  • Specificity
  • Detection Limit
  • Quantitation Limit
  • Linearity
  • Range

For further details please refer ICH Guidelines Q2 (R1)

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Thank you very much sir

What is the difference between method transfer and method verification sir

What is the critical parameter in method validation

Analytical method transfer means transferring method from one department / function (Like R & D) to the other department / function (QC Lab). Generally, any new anlytical method is developed and validated by R & D. And then it is transferred to QC Laboratory which is used by QC Analysts for routine analysis of that product. on day to day basis.
Method verification is performed in above case by QC Laboratory analyst to ensure that the validated method which is transferred by R & D will work satisfactorily in QC laboratory or not. This is beacuse the analytical instruments, HPLC / GC columns, Chemicals, Reagents and analysts are different, also the QC Lab environmental conditions may be different. Therefore, only partial validation can be done as method verification.

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Similarly, if pharmacopoeial method is used as such without making any changes then validation may not be required. Only method verification is enough.

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There are no critical parameters as such in method validation. All the required parameters are important.

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Thank you Sir good night

Kfr reaction is oxidation or reaction reaction tell me Sir

Good morning Sir,what type questions asked for analytical method validation in interview tell me sir

Karl Fischer titration is a titration method that uses volumetric or coulometric titration to determine the quantity of water present in a given analyte / sample. This method for quantitative chemical analysis was developed by the German chemist Karl Fischer in the year 1935, Today, specialized titrators (known as Karl Fischer titrators) are available to carry out such titrations.

The principle of Karl Fischer titration is based on the oxidation reaction between iodine and sulphur dioxide. Water reacts with iodine and sulphur dioxide to form sulphur trioxide and hydrogen iodide.
Methanol is used as a solvent in Karl Fischer titrations.
An endpoint is reached when all the water is consumed. The chemical equation for the reaction between sulphur dioxide, iodine, and water (which is employed during Karl Fischer titration) is provided below.

I 2 + SO2 + H2O → 2HI + SO3
H2O + SO3 → H2SO4

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Analytical method validation interview, likely questions are as follows,

  • What is the purpose of Method validation (MV) ?

  • Which test methods should be validated ?

  • Parameters to be validated

  • Explain each parameter to be validated in short & its importance

  • When re-validation should be performed ?

  • What is method verification ? And what is the difference from MV ?

  • Please give two examples of test metgods which you have validated and explain which parameters were considered for MV ?

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Thank you for such give good information Sir

Sir can you please provide me answers for above questions