Rheological Properties Of Low Viscosity Plant Gum And Montmorillonite Complex System And Its Application Research In Plant Capsules

Animal gelatin capsule is pharmaceutical excipient with glossy appearance, which can mask drug’s peculiar smell and make consumers swallow it easily. Although gelatin capsules are widely applied, their some shortcomings are insurmountable. For example, the protein in gelatin trends to produce a crosslinking reaction, resulting in an increase in the disintegration time which would block the release of drug powders in patient’s stomach. Because vegetable gum capsule can overcome the shortcomings of gelatin capsule, the preparation of vegetable hollow capsules is becoming a hot spot of research in recent years.So far, research workers have focused on the preparation and properties of vegetable hollow capsule. However, the research on rheology behavior of vegetable gum solution is ignored. Because the forming performance, production process and equipment selection are closely related with the flow performance and behavior of gum solution, the characterization and study on rheology behavior of gum solution is an important fundamental research work.As main raw materials, sodium alginate with low viscosity and agar were used to prepare the gum solution in the thesis. The rheological behavior and influence factors were studied. And the influence of process conditions on capsule formability of gum solution was researched also in detail. In addition, inorganic montmorillonite (MMT) was added into the gum solution as a component of high content to increase the capsule disintegrating rate and decrease the cost of raw materials. The effects of MMT on the rheological behavior and capsule formability of gum solution were characterized and discussed.In this thesis, sodium alginate (SA)-agar (AR), SA-AR-MMT and AR-MMT solutions were prepared, respectively. The rheological behavior of gum solution and the influence of process conditions on capsule formability were researched. Furthermore, the disintegrating property of obtained capsule was also evaluated.1. The SA-AR solution is a typical non-newtonian fluid with an obvious pseudoplastic behavior because the solution viscosity decreases with the increase of rotor speed. The apparent viscosity of SA-AR solution increases when the proportion of AR increases. Moreover, its apparent viscosity increases significantly with a decrease in solution temperature, and the initial gelling temperature of gum solution is around50℃.The preferred technological condition for the preparation of hollow capsule is as followed:m (SA):m (AR) is70:30, mixing temperature and incubation temperatures are80and55℃, respectively. And both mixing time and incubation time are40min. In the preferred process condition, the solution shows an excellent forming performance. And the obtained hollow capsules have transparent appearance. Their wall thicknesses are uniform and at the range of0.08-0.12mm, meeting Chinese pharmacopoeia requirement. In0.1mol/L dilute hydrochloric acid, the disintegration time of SA-AR hollow capsule is around50min that is significantly longer than the disintegrating time limit for gastric soluble gelatin capsule according to Chinese pharmacopoeia.2. The ternary SA-AR-MMT solution shows a shear thinned phenomenon. The apparent viscosity of SA-AR-MMT solution increases when the proportion of MMT increases. And it’s apparent viscosity increases significantly with a decrease in solution temperature.The preferred technological condition for the preparation of hollow capsule is as followed:m (SA):m (AR):m (MMT) is42:18:40, mixing temperature and incubation temperature are80and55℃, respectively. And both mixing time and incubation time are40min. In the preferred process condition, the solution shows an excellent forming performance. And the obtained hollow capsules have translucent appearances. Their wall thicknesses are uniform and at the range of0.08-0.12mm, meeting Chinese pharmacopoeia requirement. In0.1mol/L dilute hydrochloric acid, the disintegration time of SA-AR-MMT hollow capsule is less than20min that is close to the disintegrating time limit (10min) for gastric soluble gelatin capsule according to Chinese pharmacopoeia.XRD test shows that the ternary blends belong to partly intercalated hybrid materials.3. The solution temperature and blending ratio have stronger influences than rotor speed on the apparent viscosity of binary AR-MMT solution. And the rheological behavior is in accord with a pseudo plastic fluid. The apparent viscosity increases with increasing of the proportion of AR. Moreover, it’s apparent viscosity increases significantly with a decrease in solution temperature. When the solution temperature decreases to around50℃, there is a gelatination occurring in the solution.The preferred technological condition for the preparation of hollow capsule is as followed: m (MMT):m (AR) is70:30with a solid content of7%, mixing temperature and incubation temperature are90and60℃,respectively. And both mixing time and incubation time are40min. In the preferred process condition, the solution shows an excellent forming performance. And the obtained hollow capsules have translucent appearances. Their wall thicknesses are uniform and at the range of0.08-0.12mm, meeting Chinese pharmacopoeia requirement. In0.1mol/L dilute hydrochloric acid, the disintegration time of AR-MMT hollow capsule is less than10min that meets the disintegrating time limit (10min) for gastric soluble gelatin capsule according to Chinese pharmacopoeia.XRD test shows that the ternary blends belong to partly intercalated hybrid materials.