Polymeric nanoparticulate systems allow the encapsulation of bio-active substances, giving them protection against external agents and increasing the drug's bioavailability. The use of biocompatible and biodegradable polymers usually guarantees the harmless character of the formulation, and a controlled drug release is also assured. A relatively easy procedure to obtain polymeric formulations of bioactive agents is ionotropic gelation, which allows the synthesis of chitosan (CS) - sodium tri-polyphosphate nanoparticles (NPs) loading encapsulated proteins. In this work, Bovine serum albumin (BSA) model protein and a recombinant porcine alpha interferon variant were used to obtain nanoparticulate formulations. The internalization of the encapsulated material by cells was studied using a BSA-fluorescein system; the fluorescent conjugate was observable inside the cells after 20 h of incubation. The therapeutic CS-alpha interferon formulation showed a maximum of protein released in vitro at around 90 h. This system was found to be safe in a cytotoxicity assay, while biological activity experiments in vitro showed antiviral protection of cells in the presence of encapsulated porcine alpha interferon. In vivo experiments in pigs revealed a significant and sustained antiviral response through overexpression of the antiviral markers OAS2 and PKR. This proves the preservation of porcine alpha interferon biological activity, and also that a lasting response was obtained. This procedure is an effective and safe method to formulate drugs in nanoparticulate systems, representing a significant contribution to the search for more effective drug delivery strategies.

聚合纳米颗粒系统可以封装生物活性物质，从而使其免受外部因素的侵害，并提高了药物的生物利用度。使用生物相容性和可生物降解的聚合物通常可以保证制剂的无害特性，并且还可以确保药物的受控释放。获得生物活性剂聚合物制剂的相对容易的过程是离子胶凝，它可以合成壳聚糖（CS）-载有封装蛋白的三聚磷酸钠纳米颗粒（NPs）。在这项工作中，牛血清白蛋白（BSA）模型蛋白和重组猪α干扰素变体用于获得纳米颗粒制剂。使用BSA-荧光素系统研究了细胞对包封材料的内在化；孵育20小时后，可在细胞内部观察到荧光偶联物。治疗性CS-α干扰素制剂显示出最大的蛋白质释放量体外约90 h。该系统在细胞毒性测定中被发现是安全的，而体外生物学活性实验表明，在封装的猪α干扰素存在下，细胞具有抗病毒保护作用。猪体内实验表明，通过抗病毒标记OAS2和PKR的过表达，可以产生持续的显着抗病毒反应。这证明了猪α干扰素的生物活性得以保留，并且获得了持久的应答。该程序是在纳米颗粒系统中配制药物的有效且安全的方法，对寻求更有效的药物递送策略做出了重大贡献。