The present invention relates to an improved active or inactive pharmaceutical ingredient-polymer composition and process of preparation thereof. In particular, the present invention relates to an improved active or inactive pharmaceutical ingredient-polymer composition and process of preparation thereof wherein the monomer encapsulates particles of active or inactive pharmaceutical ingredient at molecular level and with controlled polymerization process the monomer turns into the said polymer coat over the said active or inactive pharmaceutical ingredient that facilitates the disclosed invention to be completed a single step process.