This paper presents the development of a dynamic sliding mode controller (DSMC) for open-loop unstable systems with time delay, based on the sliding modes concepts and internal model structures. The proposal improves the performance of the traditional sliding mode controller (SMC), both in tracking and regulation, reducing the chattering effect on the control signal. Based on the advantage of a First Order Plus Dead-Time (FOPDT) model to represent nonlinear systems, the DSMC is structured. The proposed approach is tested by computer simulations applied to a biochemical reactor operating at an unstable point. An identification method approximates this open-loop unstable process to a FOPDT unstable model.