Table 2. Overview of the quantitative influx characteristics (± 65% confidence limits) of the five investigated CPPs based on linear and biphasic modeling of the multiple time regression analysis data.

Influx parameter	pVEC	TP10	TP10-2	SynB3	Tat 47–57	Dermorphin	BSA
Linear Gjedde-Patlak model
Kin (μl/(g× min))	6.02 ± 0.29	0.05 ± 0.04	0.36 ± 0.06	5.63 ± 1.83	4.73 ± 1.23	0.63 ± 0.10	0.16 ± 0.07
Vi (μl/g)	23.13 ± 4.33	9.88 ± 0.66	10.07 ± 1.00	27.62 ± 5.58	17.43 ± 4.04	13.98 ± 0.79	15.42 ± 1.11
Biphasic model
V0 (vascular) (μl/g)	-	-	-	10.27	10.27	10.27	-
Vg (tissue) (μl/g)	-	-	-	44.47 ± 7.75	34.38 ± 9.32	13.72 ± 2.17	-
K1 (μl/(g × min))	-	-	-	29.84 ± 8.42	13.50 ± 3.88	2.54 ± 0.50	-
K (μl/(g × min))	-	-	-	≈ 1.92e-16	0.27 ± 0.46	0.03 ± 0.06	-

K_in = Unidirectional influx rate.

V_i = Initial brain distribution volume.

V₀ = Vascular brain distribution volume, experimentally determined as the brain distribution volume of radioiodinated BSA.

V_g = Tissue brain distribution volume.

K₁ = Unidirectional clearance or slope of the initial phase of the brain influx curve.

K = Net clearance or slope of the plateau phase of the brain influx curve.