Table 1.

Parameter description of Eqs. (1)–(5)

Inf	Intestinal levodopa infusion rate (mg/min)	+
a 0	Amount in first compartment (mg)	+
a 1	Amount in second compartment (mg)	+
a 2	Amount in third compartment (mg)	+
$k_a$	Absorption rate (1/min)	1/TABSa
TABS	1/$k_a$, absorption time constant (min)	28.5a
$\text{kEO}$	Effect rate (1/min)	1/TKEOa
TKEO	1/$\text{kEO}$, effect time constant (min)	21a
BIO	Bioavailability	0.88a
Q	Intercompartmental clearance (L/min)	0.58a
V 1	Volume in first compartment (L)	11a
V 2	Volume in second compartment (L)	27a
CL	Clearance rate (L/min)	0.52a
Rsyn	Endogenous levodopa synthesis rate (mg/min)	0.01a
Ce	Concentration in the effect compartment (mg/L)	+
EC50	Concentration at 50% effect (mg/L)	1.55a
gamma	Sigmoidicity factor	11.6a
BASE	Baseline effect	X
E max	Change from baseline effect	X
E	Effect ranging from − 3 to + 3	+

+, estimated thought the equations, given the parameter values; X, patient-specific values

^aPopulation parameter values as seen in Westin et al. [11]