  In this paper, we consider an inhomogeneous Doi model which was introduced by
W. E and P. Zhang [Meth. Appl. of Anal., 13 (2006), pp. 181 - 198]. We extend
their model, which couples a Smoluchowski equation to a Navier-Stokes type
equation, for active particles by introducing an additional stress tensor.
Exploiting the energetic and entropic structure of the system, we establish the
existence of global-in-time weak solutions in two and three space dimensions
for both passive and active particles. In particular, our result holds for
minimal regularity assumptions on the initial data and without restrictions on
the Reynolds and Deborah number.
