Sample collection
Cefoperazone/sulbactam (Sulperazon, Pfizer, New York, USA) with
cefoperazone 2.0 g/sulbactam 1.0 g in a 3-g ampoule was given to
patients. A dose of 3.0 g CFP/SUL for adults was added to 100 mL of
0.9% normal saline solution and was administered by intravenous
injection using an infusion pump at the usual rate for 60 min every 8 h.
Each TPE session began 10 min after the end of the CFP/SUL infusion. 3
mL blood anticoagulated with EDTA were collected from median cubital
vein. To evaluate the effect of TPE on the pharmacokinetics of CFP and
SUL, whole blood samples were
collected during two sessions.
Session I, the third dose of CFP/SUL was administered on the first day
with TPE. Serial venous blood
samples were collected at time 0 (trough concentration), time 1 (peak
level, 10 min before TPE), and time 2, 3, 4, 6, 8 h after the start of
drug infusion.
An
aliquot was also taken from the effluent port of
plasma eliminated during TPE.
Session II, before the following
day’s TPE, a series of venous blood samples were collected respectively
at the same time points at the sixth CFP/SUL administration without TPE.
Whole blood samples were centrifuged at 4°C at 3000 rpm for 10 min, and
then the plasma was separated. All plasma samples were stored at -80°C
until analysis.