Not blinding sampling times [Bioanalytics]

posted by Helmut Homepage – Vienna, Austria, 2018-08-19 19:06 (766 d 14:58 ago) – Posting: # 19175
Views: 2,337

Hi ElMaestro and Scopy,

» Blinding wrt time point would be interesting. It may be the solution to a non-existing problem, though? You mean they could use that info to create smooth profiles that more or less correspond to the expectation in terms of e.g. t half etc? I'd say that is theoretically correct, they could do that.

Even if substantial carry-over is not apparent in method validation (which would call for injecting mobile phase between samples), it exists. The EMA’s GL tells us:

If it appears that carry-over is unavoidable, study samples should not be randomised. Specific measures should be considered, tested during the validation and applied during the anal­ysis of the study samples, so that it does not affect accuracy and precision. This could include the injection of blank samples after samples with an expected high concentration, before the anal­ysis of the next study sample.

For decades the Canadian GL called for completely randomized samples but HC abandoned this requirement for good reasons. If one doesn’t want to give the scheduled time points, that’s fine. But still give an index of sample / subject / period. Then the analyst can minimize carry-over by alternating periods and increasing indices, e.g.,

Sub1Per1Spl1 – Sub1Per2Spl1 –
Sub1Per1Spl2 – Sub1Per2Spl2 –
… –
Sub1Per1Spln – Sub1Per2Spln.

Of course, this is best only for BE (where one can expect similar profiles). In BA (say EV vs. IV) inject all samples of one period followed by the other.

Dif-tor heh smusma 🖖
Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes

Complete thread:

 Admin contact
21,072 posts in 4,394 threads, 1,468 registered users;
online 6 (2 registered, 4 guests [including 1 identified bots]).
Forum time: Thursday 10:04 CEST (Europe/Vienna)

Enlightenment is man’s emergence from his self-imposed nonage
for which he himself was responsible.
Nonage is the inability to use one’s own intellect
without the direction of another.    Immanuel Kant

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz