Na Dong Hee, Youn Yu Seok, Park Eun Ji, Lee Jeong Min, Cho Ock Ryun, Lee Kang Ro, Lee Sang Deuk, Yoo Sun Dong, DeLuca Patrick P, Lee Kang Choon
College of Pharmacy, SungKyunKwan University, 300 Chonchon-dong, Jangan-ku, Suwon City 440-746, Korea.
J Pharm Sci. 2004 Feb;93(2):256-61. doi: 10.1002/jps.10537.
The purpose of this study was to evaluate the stabilization of salmon calcitonin (sCT) by PEGylation in nasal mucosa. Degradation of native sCT in the homogenates of rat nasal mucosa was investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The initial cleavage of sCT was due to tryptic-like endopeptidase activity, and the subsequent degradation followed the sequential pattern of aminopeptidase activity. To prepare PEGylated sCT resistant to the proteolytic degradation, the lysine residues susceptible to tryptic activity were selectively PEGylated by controlling reaction pH. The PEGylated sCT showed strong resistance against enzymatic degradation in rat nasal mucosa, with 56-fold prolonged half-life compared with that of native sCT. In the MALDI-TOF MS spectrum, the PEGylated sCT did not show any degradation peak for incubation of 120 min in the homogenates of rat nasal mucosa. The improved stability may be responsible for enhancing nasal absorption of PEGylated sCT.
本研究的目的是评估聚乙二醇化对鲑鱼降钙素（sCT）在鼻黏膜中的稳定性的影响。通过基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）研究了大鼠鼻黏膜匀浆中天然sCT的降解情况。sCT的初始裂解是由于类胰蛋白酶的内肽酶活性，随后的降解遵循氨肽酶活性的顺序模式。为了制备抗蛋白水解降解的聚乙二醇化sCT，通过控制反应pH值，对易受胰蛋白酶活性影响的赖氨酸残基进行选择性聚乙二醇化。聚乙二醇化sCT在大鼠鼻黏膜中表现出对酶促降解的强抗性，与天然sCT相比，半衰期延长了56倍。在MALDI-TOF MS谱图中，聚乙二醇化sCT在大鼠鼻黏膜匀浆中孵育120分钟未显示任何降解峰。稳定性的提高可能有助于增强聚乙二醇化sCT的鼻吸收。
