Table 5

Recovery and characterization of radioactivity excreted from rats and dogs after s.c. administration of [¹⁴C]cetrorelix until 48 h post dose

Species	Dose	Specimen	Radioactive Metabolite Fractions Identified
Species	Dose	Specimen	cetrorelix	(1–4)^5-a	(1–6)^5-a	(1–7)^5-a	(1–9)^5-a	unknown
			% of Administered ¹⁴C Dose
Rat	0.1 mg/kg	Urine	25
		Feces	3	42	14	12	1	0.2
	1 mg/kg	Urine	15
		Feces	^5-c
		Bile	23	4	2	5	3	0.7
Dog	0.1 mg/kg	Urine	47
		Feces	10	9	3	19
	1 mg/kg^5-b	Urine	34
		Feces	^5-c
		Bile	3	0.2	1	5	2

↵5-a Truncated peptides of the parent decapeptide cetrorelix.
↵5-b The study was exclusively designed to obtain material for isolation/identification of metabolites; therefore, recovery was incomplete due to 10-fold increased dose and the short sampling interval.
↵5-c Not investigated, total ¹⁴C fraction was only 1%.