Alginate microspheres (AMs) have received much attention as a novel drug delivery system owing to various advantages of alginate such as inexpensiveness, nontoxicity, biocompatibility and biodegradability. The well-designed fabrication method is essential to achieve desired AMs suitable for specific drug delivery system. Reports on AMs preparation techniques have increased rapidly in the last decade. A number of synthesis parameters have been investigated for the improvement of physical, chemical and biological properties of AMs. Hence, this review summarizes the work to date on the fabrication techniques of AMs for drug delivery system, including spray-drying, extrusion and emulsification/gelation technique. Besides, the influence of various factors such as alginate concentration, oil phase, surfactant, cross-linker concentrations, cross-linking time, stirring speed, model drug and drug content on the morphologies, properties and encapsulation efficiency (EE) of AMs via extrusion and emulsification/gelation technique are summarized. Before embarking on the development of any drug delivery system, a thorough understanding of drug release mechanism and factors that impact the drug release profile are essential, which are also covered in this review.
The critical feature in trachea replacement is to provide a hollow cylindrical framework that is laterally stable and longitudinally flexible, facilitating cartilage and epithelial tissue formation. Despite advanced techniques and sources of materials used, most inherent challenges are related to the complexity of its anatomy. Limited blood supply leads to insufficient regenerative capacity for cartilage and epithelium. Natural and synthetic scaffolds, different types of cells, and growth factors are part of tissue engineering approaches with varying outcomes. Pre-vascularization remains one of the crucial factors to expedite the regenerative process in tracheal reconstruction. This review discusses the challenges and strategies used in tracheal tissue engineering, focusing on scaffold implantation in clinical and preclinical studies conducted in recent decades.
In this study, chitosan-poly(methacrylic acid-co-N-isopropylacrylamide) [chitosan-p(MAA-co-NIPAM)] hydrogels were synthesized by emulsion polymerization. In order to be used as a carrier for drug delivery systems, the hydrogels had to be biocompatible, biodegradable and multi-responsive. The polymerization was performed by copolymerize MAA and NIPAM with chitosan polymer to produce a chitosan-based hydrogel. Due to instability during synthesis and complexity of components to produce the hydrogel, further study at different times of reaction is important to observe the synthesis process, the effect of end product on swelling behaviour and the most important is to find the best way to control the hydrogel synthesis in order to have an optimal swelling behaviour for drug release application. Studied by using Fourier transform infra-red (FTIR) spectroscopy found that, the synthesized was successfully produced stable chitosan-based hydrogel with PNIPAM continuously covered the outer surface of hydrogel which influenced much on the stability during synthesis. The chitosan and PMAA increased the zeta potential of the hydrogel and the chitosan capable to control shrinkage above human body temperature. The chitosan-p(MAA-co-NIPAM) hydrogels also responses to pH and temperature thus improved the ability to performance as a drug carrier.