The Construction Of Konjac Glucomannan Colon-Specific Drug Delivery And In Vitro Evaluation

Konjac glucomannan(KGM),a kind of natural polysaccharides which is safety,non-toxic,and has extensive sources,as well as excellent biodegradability, is very suitable as carrier material of oral colon-specific drug delivery system (OCDDS). Cassava starch(CS) and sucrose esters(SE) are green renewable and specific resources of guangxi, as the accessories of sustained release matrix tablets, not only broaden their applications, but also improves its added value.This paper aim at improving the nature of the sol and the properties of the gel by using KGM mixed with CS, studied the blending synergy of KGM and CS.KGM oxide (OKGM) were dry heated after blended with CS, studied the effect of dry heat temperature, time and CS content on the swelling and solubility of the blends. Its structural was characterized and its surface morphology change was analysised by modern analytical tools. Dry heating blends sustained release matrix tablets were prepared, and their drug release performance and mechanism were discussed. On this basis, the surfactant SE was added, the effect of HLB value of SE on the physical properties and the drug release performance and mechanism of the the BSA matrix tablets and4-ASA matrix tablets were studied. The experimental results showed:The CS mixed with KGM can produce synergies, the viscosity of blending sol was greater than the sum of both. the best conditions were3.0%polysaccharide, KGM/CS ratio was3:7, swelling temperature was80℃, pH7.0, swelling time30min, and the viscosity of KGM/CS blending sol was41.391×103cP, the transmittancy was7.339%. The optimum conditions to prepare KGM/CS blending gel were4.0%polysaccharide, the swelling temperature was90℃, the geatinization time was30min, and the KGM/CS blending gel strength under optimal conditions was130.74g, and the springiness was0.9865.OKGM were dry heated after blending with CS at150℃for8h, and the blends with a high hydrophobicity and a low degree of swelling, and the descending order of hydrophobicity and swelling of the blends with various starch content:20%>30%>40%>10%. DSC showed that the thermal stability of KGM after oxidating modified were increased, thermal stability of OKGM/CS blended with the CS content20%and30%were increased, the CS content of10%and40%were reduced. SEM showed that OKGM particle surface was smoother than KGM, after dry heating the starch particles were adhesion with OKGM.The prescription of OKGM/CS matrix tablets design found the best prescription were0.048g OKGM/CS with20%CS,0.048g methyl cellulose (MC),0.012g bovine serum albumin(BSA),0.008g magnesium stearate,the best tableting pressure was8kN. The initial release of the best prescription matrix tablets was little, and the release sustained for a long time. The matrix tablets T50was6.75h, the MDT value was6.33h,T90was12.92h. The drug release mechanism of OKGM/CS matrix tablets was skeleton dissolution, part of the matrix tablets accompanied by a dual release mechanism of drug diffusion.SE incorporation improved the physical properties and the drug release performance of the matrix tablets, and the higher HLB value of the SE, the worse effect of sustained-release,its also applied to the insoluble drug4-ASA. The drug release mechanism of matrix tablets with SE was skeleton dissolution.