Study On Layer-by-Layer Assembly Of Polyaspartic Acid/Branched Polyethyleneimine Films For Double Simulated Drugs Delivery

Layer-by-layer assembly is a simple method for preparing nanometer scale multilayer flim by alternately depositing oppositely charged polymers. In this paper, layer-by-layer PASP/b-PEI was prepared by using polyaspartic acid(PASP) and branched polyethyleneimine(b-PEI) as primitives. The multilayer film was as a carrier, small analog molecule drugs methyl orange(MO) and PONCEAU 4R(P4R) was discussed. Loading performance and release properties after loading and the factors that influence the loading process was discussed. At the same time, the process of loading and the results of sustained release was characterized.During the process of preparation PASP/b-PEI, the effect of pH on the film formation by adjusting pH values of building primitive PASP and b-PEI solution was investigated. Layer-by-layer assembly films built by different pH combination polymers were characterized by UV and the optimum p H values of PASP(3.8) and b-PEI(8.3) were obtained. The pattern of each of the layers was observed by polarized light microscopy.layer-by-layer assembled film(PASP/b-PEI-MO)*20 was prepared using polymer composite b-PEI-MO and PASP as building primitives and a single loading performance of small analog molecule drugs methyl orange was studied. The experiment also explored the methyl orange concentration in polymer composite effects on loadings. The optimum concentration 1.5mg/ml of methyl orange was obtained. By changing p H of the polymer composite solution, pH effect on the film formation was explored and the optimum p H values 3.8(PASP) and 8.3(b-PEI-MO) were obtained,(PASP/b-PEI-MO)*20 building process was characterized by UV, and absorbance values of small analog molecule drugs methyl orange appeared jagged upward trend with the growth of the number of films were found. It was proved that small analog molecule drugs methyl orange could be loaded in(PASP/b-PEI-MO)*20 with a form of polymer composite well. Under the condition of 37 degrees saline, methyl orange could completely release within 30 hours from(PASP/b-PEI-MO)*20. It was indicated that methyl orange had a good release effect. Methyl orange soaking loading performance in(PASP/b-PEI)*20 was studied and methyl orange could be loaded in(PASP/b-PEI)*20 with a saturation loading for a certain number layers multilayer. In the later sustained-release experiment, It was found that methyl orange could completely release from layer-by-layer assembly film and had a good release effect. Another small analog molecule drugs PONCEAU 4R was single loaded, it had also been proved that PONCEAU 4R had a good loading and sustained release property with a sustained period about 14 days.To further explore dual analog drug molecules loading, layer-by-layer assembly film with polymer composite b-PEI-MO was prepared and b-PEI-P4 R and polymer PASP as building primitives, which the first 15 T with b-PEI-MO and PASP as building primitives after 5T with b-PEI-P4 R and PASP as building primitives. The process was tracked and monitored by UV. It was found that two small analog molecule drugs could be loaded in a layer-by-layer assembly film. The later sustained-release experiments showed that dual analog molecules drug were able to release in saline from multilayers with a sustained-release period about 30 hours of methyl orange and 14 days of PONCEAU 4R. Finally, the soaking loading performance of two small analog molecule drugs was studied. The results showed that the presence of substance had a huge impact on another substance soaking loading and the impact increased with the increasing of concentration.