Bioequivalence and Bioavailability Forum • randomization

Alex
☆

Austria,
2013-09-19 17:51
(4660 d 11:14 ago)

Posting: # 11526
Views: 3,449

randomization [Design Issues]

Dear all!

I have a question regarding randomization and I would be happy to read your suggestions. The study design is as follows:

I have two test items (T1 and T2) and one control item (C)
two treatments can be tested simultaneously (within the same subject) leading to two separate readouts
per subject (n=4, pilot study), between 8 and 13 pairs of applications will be performed (= 16 to 26 applications) so it will start with two simultaneous applications, then the next two and so on (maximum 13)
it cannot be extended to three simultaneous applications

so we have the following possible pairs of applications: T1+C, T2+C, T1+T2

How should randomization look like for a subject?

a 2:1 randomization using only T1+C and T2+C
or a 1:1:1 randomization using all three possible pairs?

Am I correct that there is a risk, that the study will not be balanced as the number of pairs are not fixed and will vary between 8 and 13? is this a problem?

Thank you very much for your help!

Kind regards,
Alex

Dr_Dan
★★

Germany,
2013-09-20 12:23
(4659 d 16:41 ago)

@ Alex
Posting: # 11530
Views: 2,658

randomization

Post reply

Dear Alex
Sorry, but I am not sure if I can follow your thoughts. Just for clarification, I guess your treatments are not systemically available, right? (otherwise they could not be administered simultanously) You are planning a Pilot study with a three way cross-over design, right? In each period you have 4 subjects but three pairs of simultaneous application which leads to imbalances, right?

Subjects in rows
1: T1+C; T2+C; T1+T2
2: T2+C; T1+C; T1+T2
3: T1+T2; T1+C; T2+C
4: T1+C; T1+T2; T2+C

Treatments/Period in columns
3xT1; 3xT1; 2xT2
2xT2; 2xT2; 4xT2
3xC; 3xC; 2xC

each Treatment occurs 8 times

Please correct me if I am wrong.
Kind regards
Dan

—
Kind regards and have a nice day
Dr_Dan