Extraction level and kinetics are key parameters that control the properties of materials made of polymer blends when they are in contact with a liquid medium. Poly(vinylpyrrolidone) (PVP)poly(methacrylate) polymer blends (PBs), interpenetrating polymer blends (IPBs), and semiinterpenetrating polymer networks (s-IPNs) were synthesized in the film form by a UV curing process (except in PBs cases). The extent of PVP extraction from these materials by water was investigated by monitoring the PVP content in the extracting medium. PW was generally well extracted from PBs and from IPBs, but only partially from s-IPNs and one IPB. The strong limitation of PVP extraction in the last cases was attributed to the high cross-linking density of the matrices. It can be explained by a blocking of the reptation linear chains by nooses around branches of the network. The diffusion coefficient of PVP in these materials, which was calculated by fitting kinetics data with a solution of second Fick’s law, depends strongly on the network chemical nature and PVP content in the poly(methacrylate) matrix. Extraction of a polymer from s-IPN could then be prevented by choosing properly the composition of the blend and the nature of the poly(methacrylate) component.