Bioequivalence and Bioavailability Forum

Hi Forum,

Greetings!

This is a query regarding Mean IS response consideration for calculating IS variabilities in subject samples or unknown samples having endogenous drug concentration.

When analyzing samples having endogenous drug concentrations in matrix,
Stripped matrix or bovine serum albumin (BSA) was used for calibration curve standards and to validate this standards quality control samples prepared in same Stripped matrix or bovine serum albumin were used. However to mimic the subject samples or unknown samples unstripped quality control samples were also used. Analysis was done and concentration was calculated by suitable correction factor by standard addition or subtraction method.

For knowing the IS variability (50% difference) in subject samples for repeats, which is the idle process to be followed:

Process 1: Mean IS response to be considered from only accepted Quality control samples prepared in same matrix mimicing subject samples or unknown samples.

Process 2: Mean IS response to be considered from both calibration standards, quality control samples in stripped matrix or BSA as well as Quality control samples prepared in same matrix mimicing subject samples or unknown samples.

Note: Recovery of internal standard was similar in both the type of matrices (Stripped/BSA and Unstripped matrix).

Kindly clarify.