Table 2.

Mean concentrations and unbound fractions of antimuscarinic agents in rat tissues following subcutaneous dosing

Compound	Dose (mg kg−1)	Plasma concentration (ng ml−1)	Brain concentration (ng g−1)	CSF concentration (ng ml−1)	fup	fub
Trospium	1.0	106 ± 85	2.68 ± 1.31	0.33 ± 0.34	0.72 ± 0.02	0.19 ± 0.02
5-HMT	0.3	27.3 ± 1.3	4.38 ± 0.58	0.74 ± 0.07	0.72 ± 0.03	0.16 ± 0.01
Darifenacin	0.3	39.0 ± 5.8	3.04 ± 0.10	0.17 ± 0.04	0.074 ± 0.006	0.019 ± 0
Solifenacin	1.0	59.3 ± 4.6	180 ± 55	10.9 ± 1.7	0.13 ± 0.02	0.012 ± 0.001
Tolterodine	0.3	20.8 ± 2.7	61.3 ± 6.7	1.07 ± 0.17	0.32 ± 0.02	0.025 ± 0.005
Oxybutynin	0.3	22.5 ± 5.2	141 ± 27	0.71 ± 0.26	0.019 ± 0.001	0.01 ± 0
N-methylscopolamine	0.3	45.9 ± 6.3	2.33 ± 0.92	0.38 ± 0.25	0.96 ± 0.06	0.40 ± 0.06
Scopolamine	0.3	29.8 ± 2.0	102 ± 6	27.9 ± NA	0.83 ± 0.04	0.46 ± 0.02

Values in the table are mean ± SD for three separate determinations. f_ub, unbound fraction in brain; f_up, unbound fraction in plasma.