Development On Gelatin-Mineral Composite Hard Capsule Shells

Gelatin-mineral composite films and gelatin-mineral composite hard capsule shells were prepared using fish skin gelatin and calcium carbonate microcrystalline and their performance indexes were studied in this paper. Furthermore, a kind of calcium carbonate microcrystalline was compounded by double decomposition method to study the performance indexes of gelatin-mineral composite films and gelatin-mineral composite hard capsule shells.The best process conditions to compound the smallest diameter synthetic calcium carbonate microcrystals were determined for calcium chloride concentration 0.3mol/L, sodium carbonate concentration 0.5mol/L, the concentration of ethanol 40%at 25 degrees Celsius. Under this condition, the average crystallite diameter of the synthetic calcium carbonate is minimal for 5.40μm And then, five kinds of high purity, different particle sizes, crystal calcium carbonate microcrystal lines whose particle sizes were 5.40μm, 7.03μm,10.04μm,13.98μm and 16.63μm were filtered on the basis of optimum technology by calcium carbonate particle size, crystal form, crystalline feature, infrared spectrum, X-ray diffraction characterization and so on.Film-forming liquid of gelatin films and gelatin-mineral composite films was studied for its gel strength, mechanical property, water vapor permeability (WVP), microscopic structure and dissolve situation in gastric fluid. Compared with gelatin films, gelatin-mineral composite films which were added to calcium carbonate microcrystalline had high gel strength, good mechanical property, small WVP and a rough microscopic structure. The results of the test showed that the gelatin-mineral composite films dissolved slowly within 1min and dissolved faster after 1min in the simulated gastric fluid and their dissolution rate was higher than gelatin films.Optimum technological condition was determined to gelatin 28.01%, calcium carbonate 13.95%, particle size of calcium carbonate 5.40μm, glycerin 6.42%, triethyl citrate 4.43%, titanium dioxide 1.20% and methyl silicone oil 3.00% according to single factor tests and response surface experiments. The wall-forming of the capsule shells is 10.44. Tests of physicochemical indexes, microstructure, formation mechanism of the composite structure, dissolution rate, stability of hollow capsule shells of gelatin-minerals showed that their brittleness, disintegration time and ignition residue were 2.03%,5.50min, 26.98%. In addition, their microstructure was rough. The results of dissolution rate were 8min and the capsule shells had a well stability.