Table 2.

Simultaneous plasma and CSF PK parameters after a single 5 mg/kg dose in non-human primates

Animal	τ (h)	Ka (h −1)	V1/F (L/kg)	Ke (h −1)	K12 (h−1)	K21 (h −1)	$t_{1/2}^{\text{P}}(\text{h})$	CSF CL (ml/h)
1	0.76	12.5	41.5	0.23	7.0 × 10−6	0.805	3.0	8.1
2	0.78	53.5	40.0	0.18	4.7 × 10−6	0.420	3.9	4.2
3	2.75	44.2	24.2	0.16	16.5 × 10−6	0.913	4.3	9.1
Mean	1.43	36.7	35.2	0.19	9.4 × 10−6	0.71	3.7	7.1
SD	1.14	21.5	9.6	0.04	6.3 × 10−6	0.26	0.7	2.6

τ time-delay for absorption of oral drug, K_a absorption rate constant, V₁/F model-estimated apparent volume of distribution, K_e plasma elimination rate constant, K₁₂ rate constant for transfer from plasma to CSF, K₂₁ rate constant for transfer from CSF to plasma, $t_{1/2}^P$ model-estimated plasma half-life, CSF CL clearance from CSF