| Objective Chuanping sustained release tablets were used as a model drug to descirbesustained release preparation of Traditional Chinese Medicine in vitro release mechanism,and to forecast how drug release, which provided experimental evidences and theoreticalfoundations for prescription design and optimization.Method To study in vitro release rate of Chuanping sustained release tablets by9kindsof prepared materials, on the basis of it, Ritger-Peppas release model was fitted, and rate ofswelling and erosion in the process of in vitro release were determined. Meanwhile, thethickness of gel layer and wetting layer, gel strength and the change of dropped particles indissolution medium were determined by stereo microscope, texture analyzer and laser particle size analyzer. Above all, chuanping sustained release tablets in vitro releasemechanism was described.Results①9kinds of Chuanping sustained-release tablets in vitro release study showed thatthe cumulative release rate of Chuanping sustained release tablet4was more than95%at6.0h, and the cumulative release rate of Chuanping sustained release tablet3orChuanpingsustained release tablet9achieved85%at12.0h, and the cumulative release rate of otherChuanping sustained release tablets were all up to90%at12.0h. Ritger-Peppas releasemodel fitting results showed that, except Chuanping sustained release tablet4, the R valueof the others were close to1and the fitting results were ideal.②The release of9kinds ofChuanping sustained release tablets and swelling rate were in positive proportion before4.0h or6.0h, but they were in inverse proportion after4.0h or6.0h, and their cumulativeerosion rates were less than50%at12.0h.③Wetting layer was not obviously observed inChuanping sustained release tablets of Chuanping sustained release tablet6by stereomicroscope from9kinds of Chuanping sustained release tablets. However, the others havethree interfaces (gel layer-wetting layer-glass core), and the thickness of their gel layersand wetting layers changed regularly in the process of in vitro release.④The gel strength of9kinds of Chuanping sustained release tablets were: Chuanping sustained release tablet6＞Chuanping sustained release tablet3＞Chuanping sustained release tablet1＞Chuanpingsustained release tablet2＞Chuanping sustained release tablet4＞Chuanping sustainedrelease tablet9＞Chuanping sustained release tablet8＞Chuanping sustained release tablet7＞Chuanping sustained release tablet5. Chuanping sustained release tablet4at1.0h to2.0h, Chuanping sustained release tablet5and Chuanping sustained release tablet9at2.0hto6.0h, Chuanping sustained release tablet6at1.0h to2.0h and4.0h to6.0h, Chuanpingsustained release tablet7,8at2.0h to4.0h, their gel strength maintained at a certainvalue.⑤In9kinds of Chuanping sustained release tablets, the dropped particle size ofChuanping sustained release tablet4was bigger than the others; and the dropped particlesize of Chuanping sustained release tablet1,2,3were less than Chuanping sustainedrelease tablet5,6and Chuanping sustained release tablet7,8,9, and the dropped particlesize of Chuanping sustained release tablet5,6were greater than the Chuanping sustained release tablet7,8,9; and nearly90%dropped particle size of Chuanping sustained releasetablet9was less than Chuanping sustained release tablet7,8produced in the process of invitro release.Conclusion The above results show that three index components of Chuanping sustainedrelease tablet6and Chuanping sustained release tablet7achieve balanced release and idealsustained-release effect. Except Chuanping sustained release tablet4, in vitro releasemechanism of the other8kinds of Chuanping sustained release tablets are non-fickdiffusion, that is synergistic effect of drug diffusion and matrices erosion. At the same time,the changes of swelling rate and erosion rate, thickness of gel layer and wetting layer, gelstrength, dropped particle size in dissolution medium are studied that disintegration,swelling and erosion are found in vitro release of9kinds of Chuanping sustained releasetablets. Except Chuanping sustained release tablet4, slow release of the other8kinds ofChuanping sustained release tablets is achieved by controlling the changes of the thicknessand strength of gel layer generated in vitro release. Besides, drug release in Chuanpingsustained release tablet1,2,3dropped particles are less affected, in contrast, the others areaffected to some extent. Therefore, it is concluded that Chinese medicine sustained-releasepreparations in vitro release mechanism are much affected by the type and nature ofsustained-release materials. The thickness of gel layer and gel strength are considered byusing different sustained-release materials to control the drug release, and to forecast howdrug release, which provided experimental evidences and theoretical foundations forprescription design and optimization. |
