DC conduction equation in Matlab

Hello

I am solving DC conduction equation in Matlab. My equation is 1/r * ∂/∂r [r*σ* ∂V/∂r]=∂ρ/∂t My equation is 1D(only varies with radius) and time dependent. i am using pdepe solver.The space charge ( ρ) is the time dependent variable. But the form of matlab pdepe solver the time dependent is the unknown term V. Can alyone help me how to solve this equation with pdepe or other solvers.

Thanks