  We study the propagation of the light mesons sigma, omega, rho, and a0(980)
in dense hadronic matter in an extended derivative scalar coupling model.
Within the scheme proposed it is possible to unambiguously define effective
density-dependent couplings at the Lagrangian level. We first apply the model
to study asymmetric nuclear matter with fixed isospin asymmetry, and then we
pay particular attention to hypermatter in beta-equilibrium. The equation of
state and the potential contribution to the symmetry coefficient arising from
the mean field approximation are investigated.
