Novel chitosan and N-isopropylacrylamide-grafted-dextran-based microformulations as effective oral drug delivery system

Novel polymer network microformulations have been widely used for pharmaceutical applications. Especially challenging is to design and develop an ideal oral drug formulation due to many hostile factors in gastrointestinal (GI) tract microenvironment. Hydrogels attained striking attention for the use in controlled drug delivery systems, and for that purpose temperature- and pH-sensitive hydrogels have been extensively employed. This paper reports synthesis and characterization of innovative polymers-crosslinked hydrogel system consisted of N-isopropylacrylamide-graft-dextran (NiPAAm-g-Dex) and chitosan (Ch). Composition of the system was optimized to demonstrate distinguished encapsulation efficiency (EE) and release properties of diclofenac sodium (DS). The microspheres structure and morphology were confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR) and scanning electron microscopy (SEM), respectively. Prepared microparticles have successfully passed through the simulated gastric and small intestine and reached the intestine, where the release of DS was carried out. In vitro release studies showed smooth release profile in a controllable manner with up to 40% release of the model drug after 4 h at pH 7.20 ± 0.01. Based on the results, novel polymer microformulations show excellent potential as controlled release drug delivery system and represent a superb candidate for additional in vivo testing.