Fig. 2

Concentration of the degradation product over 24 h in samples containing 30 μg mL^− 1 of remifentanil reconstituted with sodium bicarbonate solution in isolation, and in samples containing 30 μg mL^− 1 of remifentanil reconstituted with water, 0.9% saline solution, and 20% saline solution and mixed with propofol. Data expressed as mean ± SEM, n = 3. *P < 0.05 vs. water, 0.9% saline solution, and 20% saline solution; **P < 0.05 vs. water and 0.9% saline solution; ^#P < 0.05 vs. water