A method of manufacturing a pharmaceutical active prepolymer formulation includes the steps of combining in a reactor at least one polyol compound, at least one aromatic di-isocyanate compound, and/or at least one aliphatic di-isocyanate compound, and a pharmaceutical active agent having a water or moisture content of maximum 1.0 wt/wt%. Then the at least one polyol compound and/or the at least one di-isocyanate compound is allowed to prepolymerize to integrate the pharmaceutical active agent to obtain the pharmaceutical active prepolymer formulation. The pharmaceutical active prepolymer formulation can be made into a foam for use in pharmaceutical active wound dressings.