Ionic Gelated ?-cyclodextrin-biotin-carboxymethyl Chitosan Nanoparticles Prepared As Carrier For Oral Delivery Of Protein Drugs

As a new type of biotechnology drugs,protein drugs have strong therapeutical effects,high pertinence,small side effects,and great value in the treatment of cancer,diabetes,endocrine system disorders and other diseases.However,due to its large molecular weight and poor stability,protein drug is easy to be hydrolyzed by protease,catalyzed by gastric acid,blocked by gastrointestinal absorption barrier during oral administration,and reduced bioavailablity due to the first-pass effect of liver.Therefore,it is particularly important to develop new oral dosage form of protein drug.Carboxymethyl chitosan is a derivative of chitosan with good biocompatibility,biodegradability and intestinal adhesion.It is widely used as a matrix material to drug delivery systems.In this study,?-cyclodextrin and biotin were grafted onto carboxymethyl chitosan by esterification.Then the nanoparticles were prepared by ionic gelation method using sodium tripolyphosphate as crosslinking agent.The research aim is to obtain a new delivery carrier for improve the oral bioavailability of protein drug.The physicochemical properties of polymer and nanoparticles were detected and characterized by modern analytical technology,for example,fourier transforms infrared spectroscopy,nuclear magnetic resonance,transmission electron microscopy and dynamic light scattering.Bovine serum albumin(BSA)was selected as model protein drug that was entrapped in prepared drug carrier with satisfactory entrapment efficiency(EE)and loading content(LC).Subsequently,the release profiles of bovine serum abumin from gastric fluid(SGF),small intestine fluid(SIF)and colon fluid(SIF)were studied in phosphate buffers with pH values of 1.2,6.8 and 7.4.It was found that the BSA/?-CD-Bi-CMCS NPs displayed a controlled release characteristic of pH dependency.The amount of released BSA was much lower in SGF than that in SIF and SCF,so the entrapped protein drug could be protected against the degradation of the gastric enzyme.After that,the ?-CD-Bi-CMCS NPs were used as insulin delivery carrier and the entrapment efficiency(EE)and loading content(LC)of drug were researched.The cytotoxicities of Insulin,?-CD-Bi-CMCS NPs,Insulin/?-CD-Bi-CMCS NPs were estimated by measuring their cytotoxic effect versus Caco-2 cell lines using the MTT method.The cellular uptakes of Insulin/?-CD-CMCS NPs and Insulin/?-CD-Bi-CMCS NPs were studied by confocal laser scanning microscopy image.The results showed that the prepared ?-CD-Bi-CMCS NPs had no effect to Caco-2 cells,and the cell uptake of drug was significantly increased due to the targeting effect of biotin.Therefore,the prepared ?-CD-Bi-CMCS NPs had the potentiality as promising nanocarriers for oral delivery of protein drug.