The dynamics of a dust grain in protoplanetary disc is investigated. The drag law regimes of Epstein and Stokes were explored in order to understand the forces acting on spherical dust particles. A theoretical model for dust mixed in with gas inside protoplanetary discs is derived in order to investigate three different model structures: 1. Laminar 2. Turbulent and 3. Stratification. The stratification disc model has revealed a possible evolutionary process on how dust grains can coagulate to form planetary embryos. Here, I will present preliminary results on dust grain dynamics in the initial phases of the protoplanetary disc.