| Diamondback moth antimicrobial peptides is a a helical cationic antimicrobial peptides of the relative molecular mass of 4500. Our previous studies have found that CA have good activity of the against hepatocellular carcinoma, The possible mechanism is liver cell membrane with negative charge, due to liver cancer cells high expression of phosphatidylserine, O-glycosylated mucin and other negative ions. CA can specifically bind to the cell membrane of liver cancer, cell membrane lysis occurring and mitochondrial swelling by osmosis and protein regulation, resulting in cytochrome C release and apoptosis of cells. CA anti-tumor activity of the liver showed excellent efficiency and low toxicity. But CA is sensitive to temperature, pH and other external factors, leading to its inactivation degeneration, which can also occur gather itself, or with other particles irreversible binding to loss of biological activity, so its very short half-life, in addition to, CA content of diamondback moth larvae are particularly low, the extraction and purification difficulties, two factors greatly limits the CA clinical application. The research team intends to use the PLGA as a carrier material preparation of PLGA nanoparticles of the CA, on the one hand, the problem of stability of the CA in vitro and in vivo is resolved by PLGA nanoparticles, the half-life of the CA in vivo is improved. On the other hand, the characteristics of the size of the nanoparticles can help achieve passive targeting of nanoparticles to liver tumor, so it enhance CA’s anti-liver-tumor effect.In this paper, existing CA the extraction and purification process of the research group is foundation, and its optimization. In order to reduce costs and improve the efficiency of purification purification, we increased the pre-purification process, and pre-purification of the important process parameters were optimized by the orthogonal experiment. The results showed that, after pre-purification treatment, purification cycles are significantly reduced, and the amount used in the process of purification of the resin are greatly reduced, and increases the processing amount of the single extract, meanwhile, extract the total peptide content greater than 40% and more than 60% of the CA content of the total polypeptide. Anti-hepatic tumor activity show that the conditions was less affected to the CA biological activity. Also found that there is a class of polypeptide having activity against hepatocellular carcinoma in the diamondback moth, in which CA is the main active ingredient. In the pre-purification process, the use of PBS solution, not only to avoid the problem of organic solvents residual, and the maximum reduction in the cost of the process, provide a reference for the preparation of antimicrobial peptides industrial research and technology.Nano-delivery systems have reduced toxicity and irritation, delaying drug degradation, prolong drug release time and increasing targeted release, etc. The drug encapsulated in a carrier, regulate drug release rate can be achieved, it can change the distribution of drugs in the body and improve drug bioavailability purposes, it has great application prospects. Therefore, this selection of PLGA as a carrier material, CA as a model drug, with the improved S/W/O/W double emulsion-solvent evaporation method combined with high pressure homogenization prepared CA-PLGA nanoparticles (CA-PLGA-NPs). By single factor and orthogonal of the important influencing factors experiments,2,6,14-day cumulative release rate as the evaluation index, prescription technology was optimized and screening, and to characterize the particle size, polydispersity index (PDI), the potential and other physical and chemical properties, while transmission electron microscopy (TEM) to observe its basic form, and its release behavior in vitro study. The results of the physicochemical properties showed that CA-PLGA-NPs were spherical or spherical, particle size, PDI, drug loading and encapsulation rate were respectively (358.76± 22.51) nm,0.1681±0.012 2, (10.50±0.28)%, (60.92±1.58)%. In vitro release studies showed, CA-PLGA-NPs had a good release properties, the burst was not obvious, from 2 to 10 days had a stable release period, and were found by fitting equation, fitting effect CA-PLGA-NPs with the weibull equation preferably.In this paper, the anti-HepG2 cell growth properties of the CA as an evaluation index, using comparative experiments evaluation the parameters affecting of the preparation process of CA-PLGA-NPs, the support material and degradation products to CA anticancer activity. In the experiments, the dissolution of nanoparticles in different time periods was used as cell experiments with bulk drugs, The results show that the carrier material and its degradation products on the growth of HepG2 cells without inhibition. Preparation parameters of the CA-PLGA-NPs, carrier material and their degradation products have not obvious to CA activity. |
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