明胶乙酰化修饰工艺及其对中药软胶囊囊壳的性能影响

Acetylation modification of gelatin and its effect on the properties of traditional Chinese medicine soft capsule shell

目的为了改善中药软胶囊保质期内的崩解迟缓现象,对囊壳材料明胶进行改性优化及性能评估。方法以乙二胺四乙酸二酐(EDTAD)为酰化剂对明胶进行酰化改性,以复配明胶制备胶皮,并以崩解时限为评价指标比较酰化明胶胶皮与纯明胶胶皮的性能、复配明胶胶皮和纯酰化明胶胶皮的性能;在单因素实验基础之上,以酰化取代度作为评价指标,采用响应曲面法对工艺进行优化。利用红外光谱(infrared spectrum,IR)和扫描电子显微镜(SEM)分析酰化明胶的结构特征;并分析了胶皮的力学性能。结果IR和SEM结果表明,分子侧链上的氨基与EDTAD发生了乙酰化反应,当mEDTAD/m明胶=1∶15、温度为43℃、pH为9.3时,其取代度为65.4%。采用复配明胶制备胶皮,当m明胶/m酰化明胶=10∶1时,崩解时限为18.36 min,机械性能良好。结论通过优化得到的酰化胶皮较好的改善了软胶囊囊壳的崩解迟缓现象。

Objective In order to improve the disintegration retardation of traditional Chinese medicine soft capsules within the shelf life,the capsule shell material gelatin was modified and its performance was evaluated.Methods Gelatin was acylated with ethylenediamine tetraacetic anhydride(EDTAD)as acylating agent,and the skin was prepared with compound gelatin.The properties of acylated gelatin skin and pure gelatin skin,compound gelatin skin and pure acylated gelatin skin were compared with disintegration time as evaluation index.On the basis of single factor experiment,the degree of acylation substitution was used as the evaluation index,and the response surface methodology was applied to optimize the process.The structural characteristics of acylated gelatin were analyzed by infrared spectrum(IR)and scanning electron microscopy(SEM).The mechanical properties of skin were analyzed.Results The results of IR and SEM showed that the amino groups on the molecular side chain reacted with EDTAD.When mEDTAD/mgelatin=1:15,the temperature was 43 oC and pH was 9.5,the degree of substitution was 65.4%.Using compound gelatin to prepare gelatin skins,when the dosage ratio of gelatin to acylated gelatin was 10:1,the disintegration time was 18.36 min,the mechanical properties remained good.Conclusion The acylated skin obtained by optimization can better improve the disintegration retardation of soft capsule shell.