Study on the Preparation and Property of Intelligent PVA/CS Composite Hydrogel Microsphere
|School||Southwest Jiaotong University|
|Course||Biochemistry and Molecular Biology|
|Keywords||Polyvinyl alcohol Chitosan Composite hydrogel microspheres dual pH / temperature - sensitive hydrogel|
This article describes the gel background, theory, and PVA and CS nature of its application. PVA as substrate, chemical cross-linking of modified PVA introduction of natural polymer CS composite with condensed phase separation prepared PVA / CS composite hydrogel microspheres. Chitosan excellent biodegradable and biocompatible with polyvinyl alcohol combined pH sensitivity of the use of chitosan and polyvinyl temperature sensitivity, of preparing a surface of the porous structure of the pH / temperature Sensitive hydrogel microspheres and maintain a suitable mechanical strength. The use of the hydrogel microspheres package containing polypeptide protein drug release under selective conditions, can reach, thereby improving the bioavailability of the drug. The main results are as follows: 1, with the chemical cross-linking of PVA hydrogel acetal modified aldehyde group undergoes a condensation of the hydroxyl groups on the PVA molecules and acetaldehyde, introduced in the molecular chain a partial hydrophobic acetal ring. And its performance studies and found that the swelling properties of the gel is decreased gradually with the increase of the concentration of PVA system; decreased with the increase of the concentration of acetaldehyde. Temperature sensitivity, but do not have a pH-sensitive hydrogel environment sensitivity test, drawn PVA hydrogel. 2, the use of chitosan hydrogel microspheres prepared by condensation phase separation. The experimental results show that when the concentration of the chitosan solution in 2.0% -3.5% sodium sulfate solution concentrations greater than 3.5%, can be prepared, morphology and the best strength chitosan hydrogel microspheres. In the environment of strong acid (simulated gastric juice), the swelling of the microspheres is not obvious, in the environment of a weak base (simulated colonic fluid), the swellable microspheres showed high. Therefore, the chitosan hydrogel with pH-sensitive. And with many environmental pH alternately, the hydrogel swelling behavior showed good repeatability. Chitosan solution with a solution of polyvinyl alcohol composite prepared composite hydrogel microspheres condensed phase separation. Experimental results show that the the PVA mass fraction of 5%, a the CS mass fraction of 4.5% PVA: CS = hydrogel prepared under the conditions of 2:1 into a ball tacticity better. Either in acidic or under alkaline conditions, the degree of swelling of gel decreases with increasing medium temperature, exhibit a significant temperature sensitivity. In simulated gastric fluid, the swelling of the hydrogel is not obvious;, microspheres showed high swellable in simulated colonic fluid. Showed that the composite hydrogel while having a pH-sensitive and temperature-sensitive, double-sensitive hydrogel is a pH / temperature can be achieved in the colon targeted drug delivery. 4, PVA / CS composite hydrogel microspheres release performance. The experimental results show that the PVA / CS composite hydrogel microspheres showed good efficiency of drug loading and release properties, is expected to further applications in drug release.