Model is underconstrained.
The following variables couldn't be defined:
 * Rs in component Rs
 * N in component parameters
 * d/dt Rs in component Rs
 * d/dt Cs in component Cs
 * d/dt Li in component Li
 * d/dt Ri in component Ri
 * d/dt Ci in component Ci
 * d/dt L in component L
 * d/dt Ld in component Ld
 * d/dt n in component N
 * d/dt L4 in component PKPD
 * d/dt n1 in component PKPD
 * d/dt n2 in component PKPD