关键词: 壳聚糖, 香草醛, 微囊, 萘普生, 结肠给药

Abstract: Chitosan microcapsules crosslinked with vanillin were prepared by emulsification-crosslinking method. After the chitosan aqueous phase was emulsified into the sunflower oil containing Span-80 as emulsifier by stirring to obtain microdroplets, vanillin solution was added to crosslink the microdroplets. Acetone, the optimal solvent of vanillin, was chosen by comparing the formation and shape of chitosan microcapsules. SEM photographs showed that chitosan microcapsules were spherical and had compact surface and interstitial inner structure. FT-IR and XRD spectra showed that the formation mechanism of chitosan microcapsules was due to the crosslinking reaction between amino groups from chitosan and aldehyde groups in vanillin and the dehydration of chitosan microdroplets by acetone. The influence of the degree of deacetylation (DD) and viscosity-averaged molecular weight (Mv) of chitosan and the amount of vanillin on the properties of the chitosan microcapsules was investigated. It was found that the yield and naproxen content of microcapsules and naproxen loading efficiency increased, while the rate of drug release in vitro decreased, with the increase of the DD and Mv of chitosan and the amount of vanillin. Chitosan microcapsules prepared with chitosan (DD=96.3%, Mv=6.05′105) and vanillin of which the ratio of aldehyde group to amino group is 3.75:1 can be released completely in the pH 5.6 buffer containing 0.5 g/L lysozyme simulating the environment of colon.

Key words: chitosan, vanillin, microcapsules, naproxen, colon drug delivery