Fig. 2.
1H NMR spectral analysis (600 MHz, room temperature). The urine samples were evaporated and then diluted with deuterated 20 mM sodium phosphate buffer at pH = 7.4 before 1H NMR analysis. Chemical shift (in parts per million [ppm]) is shown on the x-axes and signal intensity on the y-axes. Evaluation of rocuronium and calabadion in the urine of eight rats. (A) Free rocuronium (2 mM) shows two resonances (a and b) for the steroidal CH3 groups. (B) An equimolar mixture of calabadion 2 and rocuronium (2 mM), a′ and b′ are resonances for the bound CH3 groups of calabadion 2•rocuronium. (C) Urine sample from a rat taken 2 h after intravenous administration of rocuronium (3.5 mg/kg) followed by calabadion 2 (10 mg/kg). a′ and b′ are resonances for the bound CH3 groups of calabadion 2•rocuronium.