Zaprinast
Encyclopedia
Zaprinast was an unsuccessful clinical drug candidate that was a precursor to the chemically-related PDE5 inhibitor
s, such as sildenafil
(Viagra), which successfully reached the market. It is a phosphodiesterase inhibitor
, selective for the subtypes PDE5, PDE6, PDE9 and PDE11. IC50
values are 0.76, 0.15, 29.0, and 12.0 μM, respectively.
PDE5 inhibitor
A phosphodiesterase type 5 inhibitor, often shortened to PDE5 inhibitor, is a drug used to block the degradative action of phosphodiesterase type 5 on cyclic GMP in the smooth muscle cells lining the blood vessels supplying the corpus cavernosum of the penis...
s, such as sildenafil
Sildenafil
Sildenafil citrate, sold as Viagra, Revatio and under various other trade names, is a drug used to treat erectile dysfunction and pulmonary arterial hypertension . It was originally developed by British scientists and then brought to market by the US-based pharmaceutical company Pfizer...
(Viagra), which successfully reached the market. It is a phosphodiesterase inhibitor
Phosphodiesterase inhibitor
A phosphodiesterase inhibitor is a drug that blocks one or more of the five subtypes of the enzyme phosphodiesterase , therefore preventing the inactivation of the intracellular second messengers cyclic adenosine monophosphate and cyclic guanosine monophosphate by the respective PDE...
, selective for the subtypes PDE5, PDE6, PDE9 and PDE11. IC50
IC50
The half maximal inhibitory concentration is a measure of the effectiveness of a compound in inhibiting biological or biochemical function. This quantitative measure indicates how much of a particular drug or other substance is needed to inhibit a given biological process by half...
values are 0.76, 0.15, 29.0, and 12.0 μM, respectively.