جستجوی مقالات مرتبط با کلیدواژه « Ionic gelation » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

The development of a new drug molecule is an expensive and time consuming effort. Improving the safety efficacy ratio of old drugs has been attempted by different methods focused on each individual drug therapy, dose specification and therapeutic drug monitoring. Controlled rate delivery, slow delivery and targeted delivery are other very promising methods which have been pursued intensively. Methods for increasing bioavailability, diminishing side-effects, promoting targeted delivery and treating conditions such as blood-brain barrier disorders, are the main topics in novel drug delivery explorations. Choosing a suitable polymer is one of the most important aspects in development of a drug delivery system. In the last three decades, avast number of biomedical applications have been reported for a chitin derivative, known as chitosan. In this overview the properties of this polymer, as a natural compound, which are the main criteria for its extensive application in different areas of biomedicine are described, specifically in relation to synthesis of chitosan microparticles applied in novel drug delivery.

Biocompatible nanoparticles are widely used in biomedical engineering. In this study، chitosan nanoparticles were prepared using ionic gelation method in view of two determining factors namely method of adding chitosan into the tripolyphosphate (TPP) solution and thermal shock application. With regard to the concentration of chitosan and TPP solutions as two variables، the mean particle size of chitosan nanoparticles and their preparation yield were optimized using response surface method. According to previous studies and some preliminary experiments، the chitosan and TPP solution concentration ranges were determined to be 0. 5-2. 5 mg/mL and 0. 25-1. 25 mg/mL، respectively. The optimum values of 1. 25 mg/mL and 0. 6 mg/mL were obtained for chitosan and TPP solution concentrations in the order given. The optimized response value for the chitosan nanoparticles size was found to be 54 nm and preparation yield was 62%. The Zeta potential of resulting spherical nanoparticles was around 31 mV. Chitosan-fluorescein isothiocyanate (FITC) polymer was prepared based on the reaction between isothiocyanate functional group of FITC and primary amine functional group of chitosan. FTIR analysis was performed to demonstrate the presence of new bond formation. Labeled chitosan nanoparticles were prepared in the optimized condition using chitosan-FITC polymer. The release behavior of the labeled chitosan nanoparticles from transdermal patches was evaluated. The mean size of chitosan-FITC nanoparticles was determined to be 70 nm. Finally، it was shown that the chitosan nanoparticles were not able to release from acrylic adhesive film without using a method to speed up their diffusion.