Werle Martin, Takeuchi Hirofumi
Gifu Pharmaceutical University, Laboratory of Pharmaceutical Engineering, 5-6-1 Mitahora Higashi, 502-8585 Gifu, Japan.
Int J Pharm. 2009 Mar 31;370(1-2):26-32. doi: 10.1016/j.ijpharm.2008.11.013. Epub 2008 Nov 27.
In order to improve the systemic uptake of therapeutic peptides/proteins after oral administration, the polymer-protease inhibitor conjugate chitosan-aprotinin was synthesised and polyelectrolyte complexes between negatively charged multilamellar vesicles (MLV) and positively charged chitosan-aprotinin conjugate were prepared. It could be demonstrated that chitosan-aprotinin was capable of significantly inhibiting Trypsin in vitro in concentrations of 0.05% and 0.1%, whereas no inhibition was observed in the presence of 0.1% chitosan. The size range of the prepared MLV was between 3 and 4.5microm and the initially negative zeta potential (ca. -90mV) of the core liposomes switched to a positive value after polymer coating (ca. +40mV). Confocal laser microscopy studies showed comparable mucoadhesive properties of chitosan-aprotinin coated MLV and chitosan coated MLV. In comparison to calcitonin in solution, the area above the blood calcium concentration-time curve (AAC) after oral administration of calcitonin loaded chitosan coated MLV to rats increased around 11-fold, and around 15-fold in the case of calcitonin loaded chitosan-aprotinin coated MLV. Data gained in the current study are believed to contribute to the development of novel polymer-protease inhibitor based delivery systems.
为提高治疗性肽/蛋白质口服后的全身吸收，合成了聚合物-蛋白酶抑制剂共轭物壳聚糖-抑肽酶，并制备了带负电荷的多层囊泡（MLV）与带正电荷的壳聚糖-抑肽酶共轭物之间的聚电解质复合物。结果表明，壳聚糖-抑肽酶在浓度为0.05%和0.1%时能够在体外显著抑制胰蛋白酶，而在存在0.1%壳聚糖的情况下未观察到抑制作用。所制备的MLV的尺寸范围在3至4.5微米之间，核心脂质体最初的负ζ电位（约-90mV）在聚合物包被后转变为正值（约+40mV）。共聚焦激光显微镜研究显示，壳聚糖-抑肽酶包被的MLV和壳聚糖包被的MLV具有相当的粘膜粘附特性。与溶液中的降钙素相比，给大鼠口服载有降钙素的壳聚糖包被的MLV后，血钙浓度-时间曲线（AAC）上方的面积增加了约11倍，而载有降钙素的壳聚糖-抑肽酶包被的MLV的情况则增加了约15倍。目前研究中获得的数据被认为有助于基于聚合物-蛋白酶抑制剂的新型递送系统的开发。
