RESUMO
BACKGROUND: Cells in contact with nanomaterials can induce oxidative stress, allergic reactions, and then produce cytotoxicity and genotoxicity. Therefore, studies on nano toxicology have attracted more and more attention.OBJECTIVE: To comparatively evaluate the cytocompatibility of Pluronic (P85, F127, F87) tri-block copolymer nanoparticles modified with folic acid (FA) and polylactic acid (PLA).METHODS: Pluronic (P85, F127, F87) tri-block copolymer nanoparticles were modified with FA and PLA to synthesize a variety of amphiphilic block copolymers, including PLA-P85-PLA, FA-P85-PLA, PLA-F127-PLA, FA-F127-PLA,PLA-F87-PLA and FA-F87-PLA. The cytotoxicity of these synthesized nanoparticles was analyzed by cell morphology,cell metabolic activity and cell membrane effects in HepG-2 cells.RESULTS AND CONCLUSION: The relative growth rate of HepG-2 cells had no significant differences under 24-hour induction of various concentrations (5, 10, 20, 50, 100 mg/L) of unmodified P85, F127, and F87 nanoparticles (P > 0.05).The growth and proliferation of cells under the low concentrations (5, 10, 20, 50 mg/L) were enhanced. P85 NPs and F87 NPs could significantly inhibit cell viability at dose of 400 mg/L. In contrast, there were no significant differences towards P85, F127 and F87 nanoparticles (5, 10, 20, 50, 100, 200, 400 mg/L) modified with FA and PLA when compared with the control group (P > 0.05). These findings indicate that the modification of FA and PLA can improve the cytocompatibility of Pluronic (P85, F127, F87) tri-block copolymers, and therefore, PLA-Pluronic-PLA and FA-Pluronic-PLA nanoparticles are both good candidates for drug vectors.
RESUMO
BACKGROUND:The carriers made from biodegradable and biocompatible polymeric materials represent an exciting approach to increase the bioavailability and stability of oral y administered insulin by the chemical reaction or physical encapsulation of insulin. OBJECTIVE:To mainly review the research progress of the material types, preparation methods, physicochemical characteristics, in vitro release kinetics, and bioavailability of polymeric materials adopted as oral insulin carriers. METHODS:The first author searched PubMed, Elsevier and CNKI databases for articles (2002-01/2013-02) concerning the polymeric materials and oral insulin carriers with the key words of“polymeric biomaterials, oral insulin, carrier”in English and in Chinese. RESULTS AND CONCLUSION:Currently, there are mainly two kinds of polymeric biomaterials used for oral insulin delivery systems, that is, natural polymeric biomaterials (such as chitosan and alginates) and synthetic polymeric biomaterials. The most commonly used synthetic polymeric materials for the preparation of these vehicles are polyesters, polyacrylates and their copolymers, which are wel known for their good biodegradability, biocompatibility, and physiological properties. Although researchers have tried to develop promptly oral insulin formulation using various technologies, the reports about clinical application or commercial success have not been seen because of several questions such as polymer material as a carrier, the lower bioavailability of insulin, the quality standards and stability of the formulation. Hence, future studies wil focus on the development of a new type of polymer-based material as carriers by choosing the new materials or modifying physical and chemical characteristics of existing polymers, to avoid gastrointestinal destruction of the insulin and increase bioavailability of insulin in the body, so as to obtain the good control ed release rate and effect.