| Because of the special property of cellulose acetate, which is commonly used as the coating material for OPT, organic solvents, such as dichloromethane, ethanol, and acetone, were used as coating medium to complete the coating process. Organic solvents have many disadvantages such as explosiveness, toxicity and the high expensiveness so that coating solutions based on water were developed recently to eliminate the organic solvent. In this paper cellulose acetate aqueous dispersion was prepared by emulsion-solvent evaporation method and its properties were studied deeply. The investigation of the effects of surfactants and organic solvents were carried out. The precipitation ratio were used to sieve the optimal formulation of preparing the CA aqueous dispersion. The morphology of the particle, particle sizes distribution, viscosity of CA aqueous dispersion, and the water permeability and mechanical properties of the free films were all studied deeply. The experiment results showed that the median particle size of CA aqueous dispersion is 0.162μm and it has good stability. By using diacetin as the plasticizer the CA aqueous dispersion has excellent film forming ability. The systematic effect of the plasticizer content and thickness on the water permeability and mechanical properties of CA aqueous dispersion free films were studied.Gliclazide (GL) which is insoluble is an oral antihyperglycaemic agent widely used inthe management of non-insulin-dependent diabetes mellitus. Using the same tablet core as the GL osmotic pump tablet coating with organic solvent, a novel GL osmotic pump tablet coating with CA aqueous dispersion was prepared. Because PEO used in the core would get soft and swelling when absorbing water, an organic isolation membrane was chosen.In the paper, single factor tests were carried out on PEG content in isolation membrane, the isolation membrane weight, plasticizer content, curing time curing temperature, and... |
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