TABLE 1

Relative levels of ¹²C and ¹³C in 4′-N-methyl piperazine cyanide (CN) adducts from [¹³C]-labeled compounds (V) and (VIII) in microsomal incubations with the presence of potassium cyanide

Parent Compound	Microsome	¹³C/¹²C Ratio of CN Adducts (A)	Pathway 1 Contribution (α)	Pathway 2 (Artifact) Contribution (1-α)
II (standard)	None	0.28
V	HLM	0.62	0.24	0.76
V	RLM	0.94	0.39	0.61
VIII	HLM	0.49	0.17	0.83
VIII	RLM	0.72	0.30	0.70

HLM, human liver microsome; RLM, rat liver microsome.