TABLE 2

Pharmacokinetic parameters for gabapentin and XP13512 in plasma following administration of XP13512 to rats Values are expressed as mean ± S.D. Concentrations were determined in whole blood after intracolonic dosing.

Compound	Route	Form	Dose	N	Analyte	C₀/C_max	T_max	t_1/2	AUC_(0-inf)	F ^a
			mg-Eq GP / kg			μg / ml	h			μg·h / ml	%
XP13512	i.v.	Solution	10	6	Gabapentin	9.45 ± 1.10	0.1 ± 0.0	1.2 ± 0.1	15.6 ± 1.01	99.2 ± 6.44
					XP13512	33.6 ± 17.3	N/A	0.1 ± 0.0	1.75 ± 0.80	N/A
XP13512 sodium salt	p.o.	Solution	100	6	Gabapentin	22.5 ± 10.1	0.8 ± 0.6	8.6 ± 7.3	102 ± 9.16	64.9 ± 5.85
					XP13512	0.19 ± 0.15	0.5 ± 0.0	1.4 ± 0.5	0.50 ± 0.31	N/A
	p.o.	Solution	200	6	Gabapentin	34.1 ± 6.65	1.2 ± 0.7	4.5 ± 2.5	190 ± 15.6	60.6 ± 4.98
					XP13512	0.18 ± 0.16	1.3 ± 1.4	5.9 ± 1.8	0.95 ± 0.10	N/A
	p.o.	Solution	2000	6	Gabapentin	155 ± 41.6	1.4 ± 0.8	6.4 ± 3.5	2230 ± 357	71.2 ± 11.4
					XP13512	10.4 ± 3.32	1.5 ± 1.5	4.6 ± 2.4	63.8 ± 18.7	N/A
XP13512	p.o.	Suspension	2480	6	Gabapentin	177 ± 34.1	1.4 ± 0.5	3.2 ± 0.7	2230 ± 385	57.5 ± 9.93
					XP13512	11.6 ± 7.80	1.1 ± 0.8	6.3 ± 3.4	59.6 ± 30.7	N/A
(S)-isomer	p.o.	Solution	25	5	Gabapentin	4.77 ± 1.79	0.7 ± 0.3	2.5 ± 0.8	22.5 ± 7.10	57.7 ± 18.1
					XP13512	0.18 ± 0.10	0.8 ± 0.3	2.2 ± 0.3	0.47 ± 0.25	N/A
(R)-isomer	p.o.	Solution	25	5	Gabapentin	3.94 ± 1.46	0.7 ± 0.3	2.8 ± 0.4	19.3 ± 4.28	49.3 ± 10.9
					XP13512	0.15 ± 0.09	0.6 ± 0.2	6.2 ± 3.2	0.82 ± 0.57	N/A
XP13512	i.c.	Suspension	25	5	Gabapentin	9.17 ± 0.87	0.3 ± 0.1	1.1 ± 0.2	19.1 ± 1.60	48.7 ± 4.07
					XP13512	1.34 ± 0.75	0.3 ± 0.0	0.7 ± 0.3	0.73 ± 0.30	N/A

N/A, not applicable.
↵ a F is calculated relative to intravenous gabapentin at 25 mg/kg