The drugs that are highly lipophilic such as quinapril
and ramipril bind to ACE in tissue membranes in vitro more
avidly than the more hydrophilic agents such as captopril.
Although the mechanistic importance of inhibiting angiotensin
II formation and facilitating nitric oxide bioavailability in
injured tissues such as the heart, kidney, brain, and arteries is
undisputed, the clinical significance of tissue ACE inhibition
remains unknown.