de Barros João M S, Costabile Adele, Charalampopoulos Dimitrios, Khutoryanskiy Vitaliy V, Edwards Alexander D
School of Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, UK.
Food and Nutritional Sciences, University of Reading, Whiteknights, Reading RG6 6AD, UK.
Eur J Pharm Biopharm. 2016 May;102:115-22. doi: 10.1016/j.ejpb.2016.03.010. Epub 2016 Mar 8.
Gastrointestinal (GI) models that mimic physiological conditions in vitro are important tools for developing and optimizing biopharmaceutical formulations. Oral administration of live attenuated bacterial vaccines (LBV) can safely and effectively promote mucosal immunity but new formulations are required that provide controlled release of optimal numbers of viable bacterial cells, which must survive gastrointestinal transit overcoming various antimicrobial barriers. Here, we use a gastro-small intestine gut model of human GI conditions to study the survival and release kinetics of two oral LBV formulations: the licensed typhoid fever vaccine Vivotif comprising enteric coated capsules; and an experimental formulation of the model vaccine Salmonella Typhimurium SL3261 dried directly onto cast enteric polymer films and laminated to form a polymer film laminate (PFL). Neither formulation released significant numbers of viable cells when tested in the complete gastro-small intestine model. The poor performance in delivering viable cells could be attributed to a combination of acid and bile toxicity plus incomplete release of cells for Vivotif capsules, and to bile toxicity alone for PFL. To achieve effective protection from intestinal bile in addition to effective acid resistance, bile adsorbent resins were incorporated into the PFL to produce a new formulation, termed BR-PFL. Efficient and complete release of 4.4×10(7) live cells per dose was achieved from BR-PFL at distal intestinal pH, with release kinetics controlled by the composition of the enteric polymer film, and no loss in viability observed in any stage of the GI model. Use of this in vitro GI model thereby allowed rational design of an oral LBV formulation to maximize viable cell release.
体外模拟生理条件的胃肠道（GI）模型是开发和优化生物制药制剂的重要工具。口服减毒活细菌疫苗（LBV）可安全有效地促进黏膜免疫，但需要新的制剂来实现对最佳数量活细菌细胞的控释，这些活细菌细胞必须在胃肠道转运过程中存活下来，克服各种抗菌屏障。在此，我们使用人类胃肠道条件的胃-小肠肠道模型来研究两种口服LBV制剂的存活和释放动力学：已获许可的伤寒热疫苗Vivotif，其包含肠溶胶囊；以及模型疫苗鼠伤寒沙门氏菌SL3261的实验制剂，该制剂直接干燥在铸造肠溶聚合物薄膜上并层压形成聚合物薄膜层压板（PFL）。在完整的胃-小肠模型中测试时，这两种制剂均未释放出大量活细胞。Vivotif胶囊在递送活细胞方面表现不佳可归因于酸和胆汁毒性的综合作用以及细胞释放不完全，而PFL则仅归因于胆汁毒性。为了除有效耐酸外还能有效抵御肠道胆汁，将胆汁吸附树脂掺入PFL中以制备一种新的制剂，称为BR-PFL。在远端肠道pH值下，BR-PFL每剂量可高效且完全地释放4.4×10⁷个活细胞，释放动力学由肠溶聚合物薄膜的组成控制，并且在胃肠道模型的任何阶段均未观察到活力损失。因此，使用这种体外胃肠道模型能够合理设计口服LBV制剂，以最大化活细胞释放。
