Studies On The Hydrophobical Modification Of Alginate And Its Properties

Sodium alginate has biocompatibility, non-toxic, non-immune and biodegradability, making it become one of the candidates in medical fields. This paper describes studies on the hydrophobical modification of alginate and its application as a drug carrier. On the one hand, prepared for the hydrophobically modified alginate, obtained grafted products and crossedlinked gel; On the another hand, we will make the hydrophobically modified alginate ancapsulate hydrophilic or hydrophobic drug, and conduct the test of drug release behavior. This thesis consists of three systems:(1) Hydrophobically modified alginate were obtained through acetalization of alginate with p-methoxy benzaldehyde catalysted by an acid. The modified alginate was characterized by FTIR spectra, fluorescence, transmission electronic microscopy, scanning electronic microscopy, UV spectrum, thermal analysis. The modified alginate hydrogel was used as a drug carrier for encapsulation and release of bovine serum albumin. The results showed that drug loading ability and slow release were observed.(2)Hydrophobically modified alginate hydrogels were prepared based on the esterification of alginic acid by 1,10-decanediol that acted as a crosslinker and hydrophobic component. The hydrophobic modification and covalent cross-linking of the gels accomplished at same time by one step of the esterification. The reaction was performed in dimethyl sulfoxide solvent and at a reduced pressure for removing water. The characterization results of FTIR spectra, 1HNMR spectra, thermal analysis, XRD spectra and scanning electronic microscopy confirmed the modification products. The esterification rate reached up to as high as 26.1%, showing a satisfactory esterification result. The modified hydrogels could be used as a hydrophobic drug vehicle. The investigation results demonstrated that the modified hydrogels possessed improved drug (ibuprofen) loading rate and encapsulation efficiency, and the release rate was slowed down significantly. The release kinetics was close to zero-order release pattern.(3) Covalently crosslinked alginate hydrogel was obtained through the reaction of alginic acid and polyethylene glycol 200 catalysted by p-toluenesulfonic acid for 24 h. The characterization results of FTIR spectra, thermal analysis, XRD spectra and scanning electronic microscopy confirmed the modification products.The mechanical properties of the gel, pH sensitivity, salt sensitivity, biodegradability, encapsulation and release properties for bovine serun albumin were discussed. The results showed that the crosslinked gel had three-dimensional network structure, the degradation speed was slowed down in simulated body fluid. The investigation results also demonstrated that the modified hydrogels possessed improved drug (bovine serun albumin) loading rate and encapsulation efficiency, and the release rate was slowed down significantly. The release kinetics was close to zero-order release pattern.