The increased availability of software tools for solids-based process modeling has created opportunities to enhance pharmaceutical development through the use of models. In particular, recent work in the area of integrated process modeling has demonstrated the potential of these simulations to complement experimental studies during process development. Once developed, these models also facilitate the use of other mathematical tools like process feasibility analysis and optimization. This work will emphasize recent developments in the area of flowsheet modeling for pharmaceutical processes. Methods for feasibility analysis and optimization of these complex process models will also be discussed. These tools can play an important role in pharmaceutical process development.