Intermacromolecular associations by hydrogen bounding are of great importance both from theoretical and practical point of view. From theoretical point of view they could serve as a model for the understanding and therefore the prediction of the interactions of the biopolymers in the cells. An analysis of the interactions that appear in an IPC formed between a synthetic and a natural compound offers a better explanation of the interactions that take place at molecular level in cell as the study of the interactions between two biopolymers being very complex. In practice, they found applications especially in pharmaceutical industry for controlled (sustained and retarded) drug delivery. During the last decades considerable attention has been paid to the study of inter-macromolecular association through hydrogen bonding interactions between synthetic complementary polymers like weak polyacids and Lewis polybases. No special attentions have been paid to the studies of the intermacromolecular associations between synthetic/natural polymers containing polysaccharides, with a few exceptions as poly(acrylic acid) with methyl or hydroxyethyl cellulose. Concerning the applications, a such kind a IPC is welcome for pharmaceutical purposes due to its high biocompatibility and biodegradability (induced by the natural compound). The natural compounds mostly used for such purposes are the polysaccharides and their derivatives. Maleic acid - styrene copolymer (MAc-S) is a polyelectrolyte with a regular alternance between a strongly hydrophilic and hydrophobic groups. It derived from the hydrolysis of the maleic anhydride - styrene copolymer (MA-S). Maleic anhydride - styrene copolymer has a “per se“ pharmacological activity being an inhibitor of the spermatozoids mobility (contraceptive), It is very possible that the MAc-S to preserve the pharmacological activity of MA-S. Even if the research related to application of the maleic copolymers in medicine was started in 70s, a drug called Smancs have been already commercialized in Japan since 1994. It is a conjugate neocarcinostatine with n-butyl monoester of the MA - S copolymer. The major factors that govern the complexation formation reactions are complementarity of interacting macromolecules and their hydrophobic-hydrophylic balance. A disturbance of the macromolecular complementarity usually affects the complex formation processes. Intermacromolecular associations by hydrogen bonding of are of great importance both from theoretical and practical point of view. From theoretical point of view they could serve as a model for the understanding and therefore the prediction of the interactions of the biopolymers in the cells. An analysis of the interactions that appear in an IPC formed between an synthetic and a natural compound offers a better explanation of the interactions that take place at molecular level in cell as the study of the interactions between two biopolymers being very complex. In practice, they found applications especially in pharmaceutical industry for controlled (sustained and retarded) drug delivery. During the last tenories due has been paid to the study of inter-macromolecular association through hydrogen bonding interactions between synthetic complementary polymers like weak polyacids and Lewis polybases. No special attentions have been paid to the studies of the intermacromolecul Concerns of poly (acrylic acid) with methyl or hydroxyethyl cellulose. Concerning the applications, a such kind of a IPC is welcome for pharmaceutical purposes due to its high biocompatibility and biodegradability (induced by the natural compounds mostly used for such purposes are the polysaccharides and their derivatives. It is derived from the hydrolysis of styrene (MAc-S) is a polyelectrolyte with a regular alternance between a strongly hydrophilic and hydrophobic groups maleic anhydride - styrene copolymer has a ”per se" pharmacological activity being an inhibitor of the spermatozoids mobility (contraceptive), It is very possible that the MAc-S to preserve the pharmacological activity of MA-S. Even if the research related to application of the maleic copolymers in medicine was started in 70s, a drug called Smancs have been commercialized in Japan since 1994. It is a conjugate neocarcinostatine with n-butyl monoester of the MA - S copolymer. The major factors that govern the complexation formation reactions are complementarity of interacting macromolecules and their hydrophobic-hydrophylic balance. A disturbance of the macromolecular complementarity usually affects the complex formation processes.