How to solve this PDE ?

I have to solve Navier Stokes equation for compressible and viscous fluid which is defined by :

∆^2 P + μ/K * ∂/∂t ( ∆^2 P) = 1/C^2 * ∂^2/∂t^2 (P)

i try to use pdetool but i'm in trouble because this equation doesn't match any pde proposed by pdetool so how can i introduce it in matlab to solve it for certain boundary conditions and initial condition ? thanks