This paper presents a new method for process synthesis and economic assessment for solid drug product manufacturing, considering continuous manufacturing as a prominent process alternative. Of the three phases of drug development, phase II was targeted where the dosage form, formulation, and processing technology are determined. For a comprehensive alternative generation, a superstructure was developed that covered 9452 options for the unit level, which was combined with two options on the formulation strategy. The generated alternative was assessed by a net present value calculation model, which was adapted for dynamic cash flow consideration in the drug lifecycle. The model can incorporate uncertainty in the drug development and manufacturing in the result, and can perform global sensitivity analysis by Monte Carlo simulation. The method was demonstrated in a case study where two different scenarios regarding the price of the active pharmaceutical ingredient and the demand for the product were assumed. The results showed that when the demand and price are both low, the labor-related costs are dominant, and in the opposite case, the material-related costs become relevant. We also introduce the prototype version of the software "SoliDecision," by which the presented method was implemented for industrial application.