This study consists of two parts. In the first part of the study, new double network hydrogels composed of chemically and physically crosslinked poly( N -[Trihy;(hydroxymethyl) methyl] acrylamide) (PTHMA) and poly(vinyl alcohol) (PVA) (PTHMA/PVA DN) were prepared. The effect of the incorporation of PTHMA into PVA structures for which the polymer composition was varied from PTHMA 33% to PVA 33% was explored. Besides, the tailoring of the lower critical solution temperature (LCST) hydrogels of PTHMA/PVA DN in bufer is achieved by chemical modification and crosslinking of freely water soluble precursor polymers. By varying the crosslinker agent as well as the extent of ether/acetal linkages, the LCST can be tailored easily. But, the results exemplify the difficulties to predict the behaviour of modified thermosensitive hydrogels by simply analysing the balance of hydrophilic to hydrophobic molecular fragments. The tensile strength studies were used to test their mechanical properties. Swelling experiments were used to test the capacity of water absorption, the modification of the network parameters, the swelling kinetics, the temperature and pH swelling response and n (number that determines the type of diffusion of water). PTHMA-containing hydrogels showed values of n between 0.60 and 1.24, therefore the diffusion of water into the hydrogels were found to have non-Fickian and super case ?? traort characters. The elastic moduli and the equilibrium water content (EWC) measurements suggest that these materials may have a potential application as biomaterials. The structure of shrunken PVA at high temperature was controlled by the introduction of PTHMA into the network, to allow a slow drug release of indomethacin at 37 ?C and pH 7.4. Additionally the use of synthetic polymers may have cytotoxic effects and economically unfavorable. Clearly, the development of natural biomembrane such as Eggshell membranes (ESM) that can be used as mucoadhesives is of significant importance and no attempts have been reported to modification of natural biomembrane as mucoadhesive drug delivery systems. Eggshell membranes (ESM) regards to their unique structure and chemical composition (approximately 10% are collagens (types I, V and X) and 70-75% of other proteins and glycoproteins), exhibit interesting characteristics for many potential applications. Here we report a new concept to engineer the ESM, which provides two functions: mucoadhesion and controlled drug release. The abundant functional groups in the ESM serve as the versatile platform for further chemical modification with other desired bioactive molecules to adjust their chemical and functional properties that can extensively increase the value and utility of these biomembranes. ESM with a pore structure, high pore volume and large surface area chosen as mucoadhesive drug delivery system after functionalization (by thermo-chemical modification) with citric acid (CA). Citrate-based biomaterials (C) enable the biomaterials engineer to target a variety of regenerative engineering and biomedical applications, due to their versatile and functional material properties, tailored mechanical and degradation properties, easy synthesis reaction and modification, and scalability. CA as an important intermediate in the Krebs cycle, and because of multifunctionality, nontoxicity and biocompatibility is a key and cost effective monomer used in the design of all C, which possess tunable antioxidant, antimicrobial, adhesive, and fluorescent properties.