Stability of amiodarone in serum samples under various storage conditions

The present study was intended to examine the stability of amiodarone (Cordarex, CAS 1951-25-3) and its metabolite desethylamiodarone. For this purpose 20 ml of blood were taken from each of 12 patients treated with amiodarone and were stored, after centrifuging, at room temperature, +5 degrees C, -18 degrees C and -38 degrees C. The amiodarone and desethylamiodarone concentrations were determined by the HPLC method 30 min, 24 h, 48 h, 72 h, one and two weeks after blood-taking. It turned out that the serum levels decreased continuously as of the first day regardless of the storage temperature. Correction factors were therefore calculated for the amiodarone concentration: if the blood level determination takes place after 24 h one should add 8% to the obtained value, after 48 h 16%, after 72 h 19%, after one week 23% and after two weeks 32%.