Preparation of compound vitamin microcapsules using cross-linked gelatin as wall material / 中国药学杂志

ABSTRACT

OBJECTIVE: To study the preparation and in vitro release profile of compound vitamin microencapsules using cross-linked gelatin as wall material. METHODS: At the presence of hydrogen peroxide, the cross-linked gelatin was prepared with ferulic acid as the cross-linking agent. During this reaction, horseradish peroxidase was used as the catalyst. Influences of reaction conditions on the cross-linking degree were investigated. Compound vitamin microcapsules were prepared by spray-drying technique using the obtained cross-linked gelatin as wall material. The core material was the mixture of thiamine hydrochloride (vitamin B1), riboflavin (vitamin B2), pyridoxine hydrochloride (vitamin B6), folic acid and nicotinamide. The effect of the ratio of wall material to core material on the encapsulation efficiency and loading of the vitamins were investigated. The size and surface morphology of the compound vitamin microcapsules were characterized. The encapsulation efficiency, loading and in vitro release property of the core material were determined by fluorospectrophotometry. RESULTS: A comparatively high cross-linking degree (ca. 10%) of cross-linked gelatin was obtained under the following reaction conditionstemperature of 40°C, pH value of 8.0, gelatin concentration of 9% (W/V), ferulic acid concentration of 40 mmol·L-1 and reaction time of 24 h. The vitamins were embedded by the cross-linked gelatin and the encapsulation efficiency was more than 85%. Scanning electron microscopy (SEM) study showed that the compound vitamin microcapsules had a regular spherical shape but the majority presented rough surfaces or dents. Particle size analysis indicated that the microcapsules had a mean diameter of 15.27 μm. At the ratio of coating material to core material was 10/1 (W/W), the vitamins encapsulated with the cross-linked gelatin released completely in 30 min in simulated gastric fluid, and they released completely in 16 min in simulated intestinal fluid. They released slower than the vitamins encapsulated with the gelatin accordingly. CONCLUSION: Compound vitamin microencapsules with high encapsulation efficiency and sustained release effect can be obtained by spray-drying using cross-linked gelatin as wall material.