Rapid Determination Of Angiotensin-converting Enzyme Inhibitory Activity In Vitro And Preliminary Study On The Synthesis Of Monolithic Column For Chromatography Analysis

Angiotensin converting enzyme (ACE) inhibitor has become one of the preferred classes of antihypertensive agents for the treatment of patients with hypertension. Many synthetic ACE inhibitors such as benazepril, captopril, enalapril and so on are currently available on markets, and have been proved the great beneficial effects in the treatment of hypertension. However, some of the ACE inhibitors also exhibit a low incidence of adverse side effects such as cough, taste malfunction, skin rashes and so on. Recently, many studies have been carried out to discover the ideal ACE inhibitors with completely no adverse side effect. To study ACE inhibitors effectively, it is necessary to develop a simple, rapid, and reliable method for monitoring of ACE inhibitory activity in vitro.In comparison with packed columns, monolithic columns have shown the attractive advantages such as the lower back pressure, higher flow rate, faster separation and easier preparation process and so on, and have aroused the great interests of scientists from home and abroad.Several studies are included in the thesis:1. Angiotensin I and angiotensin II were synthesized by the Fmoc solid phase synthesis method on the Wang resins. Several investigations were made to make the synthesis process convenient.2. An improved method for determination of ACE inhibitory activity by high-performance liquid chromatography (HPLC) with UV detection was developed, which was based on a combination of hippuryl-glycyl-glycine (HGG) hydrolysis catalyzed by purified rabbitACE or human blank plasma ACE. The result demonstrates that human blank plasma ACE is also suitable for determination of ACE inhibitory activity.3. A sensitive and rapid method for determination of ACE inhibitory activity by high-performance liquid chromatography/electrospray-mass (HPLC/ESI-MS) was developed, which was based on a combination of hippuryl-glycyl-glycine (HGG) or hippuryl-histidyl-leucine (HHL) hydrolysis catalyzed by by purified rabbit ACE or human blank plasma ACE.4. Monolithic capillary columns with 530 urn inner diameters were prepared by thermally initialed, sigle-step in situ polymerization of monomer butyl methacrylate and a divinyl crosslinker ethylene dimethacrylate with water, 1,4-butanediol and 1-propanol as the porogen. The column performances and back pressures can be greatly influenced by the contents of monomer, crosslinker and porogen. Determination of ACE inhibitory activity and the preparation of butylmethacrylate-based monolithic column are the focuses of the research. In the thesis, a simple, rapid and reliable method for monitoring of ACE inhibitory activity has been developed and the prepared butyl methacylate-based monolithic capillary columns have been successfully used to rapid analysis aromatic hydrocarbon, peptides and Sudan I -IV.