چكيده فارسي :
Smart materials can undergo conformational orphase changes in response to environmental signals.Shape-memory polymers (SMPs) are an emerging class ofsmart materialswhich have the ability to change shape on demand in response toan environmental stimulus.The development of these materials isoften motivated by the requirement of specific applicationssuch as smart textiles, aerospace industry and medicaldevices1.Hydroxypropyl cellulose (HPC) is one of the most important nontoxic, biodegradable, and biocompatible cellulose derivatives, which was used in producing the smart materials.On the other hand, PCL isof particular interest in biomedical applications due to the biocompatibility, biodegradability, elasticity, sharp and tunable Tm, and good mechanical properties. Thus, PCL-based SMPs have been widely studied and prepared2. In this study, we have developed novel biodegradable drug loaded SMPs with strongly temperature-sensitive shape recovery based on HPC and PCL.Drug loaded PCL filmswith shape memory properties were prepared by performing a reaction involving HPC-g-PCL graft copolymers with hexamethylenediissicyanate (HDI) as a cross-link agent in the presence of naproxen (as a model drug). A series of HPC-g-PCL having different chain lengths of graft PCL were prepared by ring opening polymerization of CL with HPCas initiator andSn(Oct)2 as catalyst in bulk condition.Subsequently, in order to obtain cross-linked drug loaded films, appropriate amount of naproxen (as a model drug) andHDI were added into the solution of purified prepolymer at the same time. After casting and drying the films, final products were characterized by FTIR, 1H NMR DSC and XRD. The swelling ratio and gel content were determined to evaluate the cross-linking degree of grafted polymer networks. The shape-memory properties of the samples were investigated by cyclic thermomechanical tensile tests.The results of SMP behavior along with the degradation tests and in-vitro drug release studies on the drug loaded films approved that these polymers have great potential to be successfully used as biodegradable SMPs with good mechanical properties in controlled drug release.
