Montmorillonite As A Drug Delivery System: Intercalation And Preparation Of Betaxolol Microspheres

To evaluate the advantageous effect of sustained release properties ofmontmorillonite(MMT) and its mechanisms,MMT was used as a drug delivery systemcarrier and betaxolol hydrochloride is designed as the model drug，. cornea permeabilityand eye irritation of MMT was also studied.Methods has been established to determine theconcentration of betaxolol hydrochloride in vitro. The basic pHysical and chemicalproperties of betaxolol hydrochloride (solubility, apparent water partition coefficient) and invitro corneal permeability had been preliminarily researched. The results showed thatbetaxolol hydrochloride was water-soluble and had a good cornea permeability in vitro,which would be an optimizing index of the montmorillonite-drug hybrid and microspHeres.Drug loading is set as the index to optimize the montmorillonite acid-activationprocess (inCluding acid concentration, acidified time, and acidification temperature). Theintercalation of betaxolol hydrochloride into the interlayer of montmorillonite has beendemonstrated, at different pH, initial drug concentration, the proportion of MMT andbetaxolol hydrochloride, adsorbent temperature, to increase the production of MMT-drughybrid. MMT-drug hybrid had been characterized by fourier transformed infrared(FT-UR),to analysis montmorillonite intercalation mechanism and release characteristics. The resultshowed that acid-MMT had a greater drug loading. The kinetics of intercalation conformedto first order reaction. The mechanisms of MMT-drug interactions related to the ionexchange process with formation of new chemical bonds. The release of MMT-betaxololcomplex corresponded with one-kinetic equation and Elobich equation. Eudragit RS and RL had been used as host materials to prepare MMT-betaxololmicrospHeres by o/o emulsion-solvent evaporation method, for extending the drug releasebehavior further. Factors of emulsifiers, feed ratio, emulsification methods, emulsificationtime had been investigated to find the factors that affect the process of microspHeres.Drug loading, encapsulation efficiency, morpHology of the microspHeres,and the releaseperformance had been used as an indicator of the orthogonal test to optimize thepreparation technology of microspHeres. PartiCle size, surface morpHology, releasemechanism, and the corneal permeability systematic reviews of microspHeres had beenresearched.MicrospHeres suspended eye drops was prepared at last. The screening of thesuspending agents, wetting agents was discussed to design the prescription of thesuspensions with its quality inspection. Then irritation of the cornea, conjunctiva, sCleraand other organizations. Of MMT-betaxolol hydrid, its microspHeres and the suspendedeye dorps had been evaluated. The result showed that the quality of suspended eye dropswas up to standards. MMT-betaxolol hydrid, its microspHeres and the suspended eye dorpshad no obvious irritation to the eyes. Corneal permeability experiments in vitro displayedthat MMT-betaxolol hydrid and its microspHeres had slowed rate throug the cornea thanbetaxolol solution in vitro.