Bioequivalence and Bioavailability Forum

Dear Dixit!

❝ For some drugs after the blood samples are centrifuged stabilising buffers are being added to plasma samples.

… and for some drugs even immediately after blood harvesting (before centrifugation).

❝ So I would like to the criteria for buffer selection.

The one preventing degradation.
Seriously: Check the literature… instead of recreating the wheel. Examples are AgNO₃ for ISDN, H₃PO₄ for ASA, CH₃COOH for cefaclor, citrate for erythromycin, N-ethylmaleimide for captopril,…

Anyhow: You have to check the suitability of the stabiliser during development of the analytical method (haemolysis, chromatographic interference, matrix effect,…)