Delgado A, Lavelle E C, Hartshorne M, Davis S S
Department of Pharmaceutical Sciences, University of Nottingham, University Park, UK.
Vaccine. 1999 Jul 16;17(22):2927-38. doi: 10.1016/s0264-410x(99)00140-1.
Novel poly(dl-lactide-co-glycolide) microparticles for oral vaccine delivery were formulated using the enteric polymers Eudragit L100-55 and carboxymethylethylcellulose (CMEC) as stabilisers. To serve as a control, microparticles were also produced using the conventional PVA surfactant. In all three cases the antigen, ovalbumin (OVA)-loaded microparticles produced were less than 5 microm in diameter and had a spherical, smooth rounded appearance. The presence of surfactants at the microparticle surface was demonstrated by the surface analysis techniques, XPS and SSIMS. Incubation of microparticles with solutions of pepsin or trypsin led to the removal of a proportion of the antigen associated with all three systems. However, in three CMEC-stabilised microparticle formulations and one of three Eudragit formulations, a high percentage of the associated antigen was protected from removal by a solution of pepsin at pH 1.2 compared with the PVA-stabilised microparticles. In addition, with certain CMEC and Eudragit formulations a degree of protection was also afforded to the associated OVA against removal by trypsin at pH 7.4. Following the incubation of microparticles in simulated gastric fluid a higher percentage of intact antigenic OVA was detected in microparticles stabilised using CMEC than in the PVA- and Eudragit- stabilised formulations. Oral immunisation of mice with OVA-loaded microparticles stabilised using either of the three surfactants led to the induction of specific serum IgG and salivary IgA antibodies. Significantly higher levels of specific salivary IgA antibody to OVA were measured in mice immunised with the CMEC-stabilised microparticles than with the other two formulations. This novel approach in PLG microparticle formulation may have potential in increasing the efficacy of microparticulate systems for the oral administration of vaccines.
采用肠溶聚合物尤特奇L100 - 55和羧甲基乙基纤维素（CMEC）作为稳定剂，制备了用于口服疫苗递送的新型聚（dl - 丙交酯 - 乙交酯）微粒。作为对照，还使用传统的聚乙烯醇（PVA）表面活性剂制备了微粒。在所有三种情况下，制备的负载卵清蛋白（OVA）的微粒直径均小于5微米，呈球形，表面光滑圆润。通过表面分析技术X射线光电子能谱（XPS）和二次离子质谱（SSIMS）证明了表面活性剂存在于微粒表面。将微粒与胃蛋白酶或胰蛋白酶溶液孵育会导致与所有三种体系相关的一部分抗原被去除。然而，在三种CMEC稳定化的微粒制剂和三种尤特奇制剂中的一种中，与PVA稳定化的微粒相比，在pH 1.2的胃蛋白酶溶液中，高比例的相关抗原受到保护而未被去除。此外，对于某些CMEC和尤特奇制剂，相关的OVA在pH 7.4的胰蛋白酶作用下也受到一定程度的保护而不被去除。在模拟胃液中孵育微粒后，使用CMEC稳定化的微粒中检测到的完整抗原性OVA的百分比高于PVA和尤特奇稳定化的制剂。用三种表面活性剂中任何一种稳定化的负载OVA的微粒对小鼠进行口服免疫，均可诱导产生特异性血清IgG和唾液IgA抗体。在用CMEC稳定化的微粒免疫的小鼠中，检测到的针对OVA的特异性唾液IgA抗体水平显著高于其他两种制剂。这种PLG微粒制剂的新方法在提高微粒系统口服疫苗给药的功效方面可能具有潜力。
