Method Development, Validation, and Sample Analysis for Regulated Quantitative Bioanalysis Using LC-MS/MS - LC-MS in Drug Bioanalysis - page 58

Experiment #1 . Freeze-thaw stability. Following an initial freezing period of at least
24 h, each freeze/thaw cycle must include thawing and frozen storage for at least
12 h. Samples should be thawed by the same procedure as is used for study samples,
i.e., thawing, vortex mixing, uncapping and capping, ambient temperature or ice
water bath, etc. The time interval for each cycle must be at least 30 min from the
removal of the sample from the freezer to return of the sample to the freezer.

Experiment #2 . Short-term matrix bench top matrix stability. Samples should be
thawed by the same procedure as is used for study samples. Test for minimum 6 h.

Experiment #3 . Long-term matrix storage stability. Test for the designated tempera-
ture, i.e., −20 °C or −70 °C to cover the time of sample analysis.

Acceptance . Same as described in intra- and interday precision and accuracy.

5.2.9 Extract Stability

Purpose . To determine the quantitative reproducibility of processed extract samples
after storage for an extended time period under specified conditions (i.e., room tem-
perature, 5 °C).

Experiment . Reinject previously analyzed six QC replicates of low, medium, and
high QC that have been stored for a specified period under specified conditions
against the freshly prepared calibration standards. The starting point is defined as
the time when the extraction was completed. The end point is defined as the time
when the fresh extraction was completed.

Acceptance . Same as described in intra- and interday precision and accuracy.

5.2.10 Reinjection Reproducibility

Purpose . To determine the quantitative reproducibility of autosampler after storage
for an extended time period under specified conditions (i.e., room temperature, 5 °C).

Experiment . Reinject previously analyzed Accuracy/Precision batch that have been
stored for a specified period under specified condition. The starting point is defined
as the time when the extraction was completed. The end point is defined as the time
when the last acceptable QC was injected in the reinjection run.

Acceptance . Same as described in intra- and interday precision and accuracy.

5.2.11 Whole Blood Sample Collection Stability

Purpose . To evaluate the stability of the analyte in whole blood during sample
collection.