Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 52c, Josef Möller Haus, 6020 Innsbruck, Austria.
J Control Release. 2012 Feb 10;157(3):375-82. doi: 10.1016/j.jconrel.2011.09.092. Epub 2011 Oct 1.
It was the aim of this study to develop a sustained parenteral peptide (DALCE) delivery system by the immobilization of DALCE to thiolated carboxymethyl dextran-cysteine (CMD-Cys) via disulfide bond formation. The resulting CMD-Cys-DALCE conjugate displayed a 22.6±7.9% (m/m) of DALCE (mean±S.D.; n=3). The conjugation of DALCE with CMD-Cys was confirmed by FTIR-ATR spectroscopy. In vitro release studies of conjugate CMD-Cys-DALCE in the presence of 2 μM/ml reduced glutathione (GSH) being also available in the plasma showed a sustained peptide release over a time period of 8 h, because of thiol/disulfide exchange reactions. For in vivo pharmacokinetic study, DALCE and CMD-Cys-DALCE were administered intravenously to male Sprague-Dawley rats at a dose of 1mg/kg. The AUC(0-8) (ng.min/ml) was determined to be 268848±924 and 40019±495 for CMD-Cys-DALCE and DALCE, respectively. The mean residence time (MRT) was determined to be 256±8 and 53.1±9.5 min for CMD-Cys-DALCE and for DALCE, respectively. CMD-Cys-DALCE showed a more than 5-fold increased elimination half-life (p<0.01), 3-fold decreased volume of distribution (p<0.01) and a 6.7-fold decreased plasma clearance rate (p<0.01) compared to DALCE. According to these findings, CMD-Cys-DALCE seems to act as prodrug by improving half-life and decreasing plasma clearance.
本研究旨在通过二硫键将 DALCE 固定到巯基化羧甲基葡聚糖-半胱氨酸（CMD-Cys）上来开发一种持续的肠外肽（DALCE）递送系统。所得的 CMD-Cys-DALCE 缀合物显示出 22.6±7.9%（m/m）的 DALCE（平均值±S.D.；n=3）。通过傅里叶变换衰减全反射（FTIR-ATR）光谱证实了 DALCE 与 CMD-Cys 的缀合。在存在 2 μM/ml 还原型谷胱甘肽（GSH）的情况下，还可以在血浆中获得的缀合物 CMD-Cys-DALCE 的体外释放研究表明，由于硫醇/二硫键交换反应，肽可以持续释放 8 小时。对于体内药代动力学研究，以 1mg/kg 的剂量将 DALCE 和 CMD-Cys-DALCE 静脉内给予雄性 Sprague-Dawley 大鼠。分别确定 AUC(0-8)（ng.min/ml）为 268848±924 和 40019±495 用于 CMD-Cys-DALCE 和 DALCE。分别确定平均驻留时间（MRT）为 256±8 和 53.1±9.5 min 用于 CMD-Cys-DALCE 和 DALCE。与 DALCE 相比，CMD-Cys-DALCE 显示出消除半衰期增加了 5 倍以上（p<0.01），分布容积降低了 3 倍（p<0.01），血浆清除率降低了 6.7 倍（p<0.01）。根据这些发现，CMD-Cys-DALCE 通过提高半衰期和降低血浆清除率似乎起到前药的作用。
