| Objective Double coating tablets of drug-loaded montmorillonitewas successfully prepared. To observe the potency of Double coatingtablets of drug-loaded montmorillonite, different study methods wereemployed.Methods The first part: The materials to prepare PPN-MMTcomplexs are PPN and MMT. The theory of isomorphism-phasereplacement was employed to prepare PPN-MMT complexs. Finally, PPNwas successfully inserted to MMT interlamination. Drug loading ofPPN-MMT complexs was determined by PHLC. SEM was employed toobserve surface morphology of PPN-MMT complexs. To understand theinteraction of PPN and MMT, FTIR and thermoanalysis were carried out.The second part: PPN-MMT-KGM microparticles containing withPPN-MMT complexs and KGM were successfully prepared by spraydrying. SEM was employed to obtain surface morphology ofPPN-MMT-KGM microparticles. To understand the matrical interaction,XRD, FTIR and thermoanalysis were preformed. The third part: The tabletscontaining with PPN-MMT-KGM microparticles were prepared. To demonstrate biodegradation of KGM, β-mannase was employed fordegrading PPN-MMT-KGM tablets. Then, PPN-MMT-KGM tablets weresuccessfully coated with EUDRAGIT FS30D. In order to study wateruptake of double coating tablets, the tablets coated with EUDRAGIT FS30D were placed into the solution and water uptake was measured byweight variation. The double coating tablets were handled in simulatehuman digestive tract (stomach, small intestine, colon) and cumulativerelease ratio of double coating tablets was obtained. To visualizedlyobserve disintegration of the double coating tablets, rabbits wereadministrated the double coating tablets by oral gavage and X-ray imagingexamination technology was employed for observed transport of the doublecoating tablets in digestive tract of rabbits.Results The first part: PPN-MMT complexs are white or kind ofwhite powder. PPN concentrations were calculated from a linear calibrationcurve with a range of detection between0.005and0.5mg·mL-1. Accuracywas high. Repeatability and stability was well. The average recovery was99.26%. Drug loading by first loading was14%and drug loading bysecond loading was28%. SEM image showed that the surface morphologyof PPN-MMT complexs and MMT was observably different. Thecharacteristic absorption peak of PPN and MMT could be found in FTIRspectrum, respectively. The characteristic absorption peak of PPN andMMT were found in FTIR spectrum of PPN-MMT complexs, also. PPN, MMT and PPN-MMT complexs show different loss of weight in heatingprocess. The second part: SEM images show that PPN-MMT-KGMmicroparticles by spray drying were similar sphere and surface of themicroparticles was obviously shrinking. The characteristic absorption peakof PPN, MMT, KGM could be found in FTIR spectrum, respectively.PPN-MMT complexs, KGM and PPN-MMT-KGM microparticles showdifferent loss of weight in heating process. PPN-MMT-KGM tablets wereprepared using PPN-MMT-KGM microparticles and diameter of the tabletsis5.5mm. PPN-MMT-KGM tablets could be degraded by β-mannase and4%(w/v) rat cecal content and weight of the tablets markedly decreased atdifferent time. Furthermore, when concentration of β-mannase increased,loss weight of the tablets increased, also. The double coating tablets releasePPN after6h in vitro. X-ray imaging shows that double coating tabletsdisintegrated after5h.Conclusions The first part: FTIR and thermoanalysis resultsdemonstrate that PPN successfully insert into interlamination of MMT anddrug loading was well by HPLC. The second part: The materials ofPPN-MMT-KGM microparticles were PPN-MMT complexs and KGM.SEM, FTIR and thermoanalysis results demonstrate that PPN-MMT-KGMmicroparticles were successfully prepared by spray drying. The third part:β-mannase and4%(w/v) rat cecal content could be degradedPPN-MMT-KGM tablets. Double coating tablets could be delayed release of PPN. X-ray imagings in digestive tract of rabbit visualizedlydemonstrated that the disintegration of double coating tablet was in terminalileum. |
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