In this thesis, three different drug delivery systems were synthesized by following idea of porous inorganic coating of titanium dioxide (TiO 2 ) to reduce speed, and control of drug release behavior. Two of these systems were related to the controlled drug delivery systems which include Dopamine/Chitosan@TiO 2 and Insulin/Zirconium phosphate@TiO 2 . In the former system, dopamine first, was dispersed in polymeric matrix of chitosan by dissolution-evaporation of solvent (water) and then, was coated by TiO 2 by sol-gel method. In the latter system, insulin after intercalation between zirconium phosphate layers, like former system, was coated by TiO 2 . Third drug delivery system, i.e., Fe 3 O 4 /Metformin/Chitosan@TiO 2 -PEG is categorized under targeted drug delivery systems. In this system first, metformin, chitosan and Fe 3 O 4 M were mixed by dissolution-evaporation of solvent (water) and then, were coated one-pot by TiO 2 and polyethylene glycol (PEG) (by formation of covalent bonds between TiO 2 and PEG). After characterization of synthesized nanohybrid composites by different techniques such as, FT-IR, XRD, DSC, TGA, BET, FE-SEM, VSM,…, investigation of drug releases of them were measured by UV-visible determination and electrochemical method (DPV) (only first system). Drug and coating values were optimized in all three systems. Drug release in different pHs (1.2, 5.4, 7.4) were also measured and interesting results were obtained. The main innovation of this work is introduce a porous inorganic coating around the drug delivery system which improved drug release time from 10 min for first and third systems and 30 min for second system (before coating) to over 16 h (after coating). As well as, easy incorporation of drug, polymeric matrix, and Fe 3 O 4 M and simple procedure to coating with PEG (third system), were other important innovations of these projects. Results of two first projects could be applied to inject insulin and dopamine-contained drug carrier systems with fully controlled release, so that intervals of drug injections increase significantly and minimizes the need for frequent injections of the drugs. Also, by improving the method presented in this study, it is possible to achieve an easy way to convert administration of insulin or other injectable drugs from injection to oral.
