Synthetic hydrogels are an important class of biomaterials that have been used extensively as soft contact lens materials and in controlled drug delivery and wound healing applications. These polymer networks, formed by the chemical or physical crosslinking of hydrophilic polymers, can retain large proportions of water within their structures without dissolving. Permeability of these materials to water and solutes contributes to their biocompatibility. Unfortunately, hydrogels are characterized by low mechanical strength and swelling characteristics that are difficult to control, factors that have narrowed the range of their potential biomedical applications. ^ Incorporation of hydrophobic polymers within hydrogels is one method for improving key hydrogel properties. Multicomponent materials, containing both hydrophilic and hydrophobic polymeric components, can be made from block copolymers, graft copolymers, polymer blends, and a variety of networks. Within these systems, hydrophobic polymers serve to increase hydrogel mechanical strength as well as improve control of swelling and permeability. The present study focuses on hydrophilic-hydrophobic interpenetrating polymer network multicomponent systems. ^ Incentive to study novel interpenetrating networks with controllable chemical and physical properties developed from existing clinical needs. Poly(vinyl pyrrolidone), poly( 3 -caprolactone), and gelatin, three biomedically-significant polymers, were used in this investigation. Two-component semi-interpenetrating and interpenetrating polymer networks were synthesized and a variety of analytical techniques were used to evaluate chemical and physical characteristics. It was determined that composition plays a fundamental role in determining mechanical properties and controlling the extent of swelling and permeability.