Table 3.

Human plasma protein binding and microsome stability for selected compounds.

No.	X	R	G. lamblia EC50 (μM)	Plasma protein binding (% bound)	Microsome stability (% remaining at 2 h)
1	Metronidazole		6.1	<5	100
8a	Me	NHCH2(4-F-Ph)	3.5	95	88
12a	H	NHCH2(4-F-Ph)	0.5	>99	94
8h	Me	morpholine	1.6	9	97
12h	H	morpholine	8.8	78	100
8k	Me	NH-cyclohexyl	4.9	94	N.D
12k	H	NH-cyclohexyl	0.6	99	N.D

Plasma protein binding sulfamethoxazole control = 68% bound (consistent with literature 66% bound [38]); microsome stability verapamil control = 25% remaining at 2 h (consistent with literature [39]).