Zaprinast

Zaprinast was an unsuccessful clinical drug candidate that was a precursor to the chemically related PDE5 inhibitors, such as sildenafil (Viagra), which successfully reached the market. It is a phosphodiesterase inhibitor,[1] selective for the subtypes PDE5, PDE6, PDE9 and PDE11. IC₅₀ values are 0.76, 0.15, 29.0, and 12.0 μM, respectively.[2][3]

Zaprinast

Names
IUPAC name 5-(2-Propoxyphenyl)-1H-[1,2,3]triazolo[4,5-d]pyrimidin-7(4H)-one
Other names M&B 22,948
Identifiers
CAS Number	37762-06-4
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL28079
ChemSpider	5520
ECHA InfoCard	100.048.760
IUPHAR/BPS	2919
PubChem CID	5722
UNII	GXT25D5DS0
CompTox Dashboard (EPA)	DTXSID8045224
InChI InChI=1S/C13H13N5O2/c1-2-7-20-9-6-4-3-5-8(9)11-14-12-10(13(19)15-11)16-18-17-12/h3-6H,2,7H2,1H3,(H2,14,15,16,17,18,19) Key: REZGGXNDEMKIQB-UHFFFAOYSA-N
SMILES O=C1C2=C(N=NN2)NC(C3=CC=CC=C3OCCC)=N1
Properties
Chemical formula	C13H13N5O2
Molar mass	271.280 g·mol^−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Zaprinast inhibits the growth of asexual blood-stage malaria parasites (P. falciparum) in vitro with an ED₅₀ value of 35 μM, and inhibits PfPDE1, a P. falciparum cGMP-specific phosphodiesterase, with an IC₅₀ value of 3.8 μM.[4]

Zaprinast has also been shown to activate the orphan G-protein coupled receptor known as GPR35, both in rats and humans,[5] however, the clinical significance of this has yet to be determined.

References

1. Choi, SH; Choi, DH; Song, KS; Shin, KH; Chun, BG (2002). "Zaprinast, an inhibitor of cGMP-selective phosphodiesterases, enhances the secretion of TNF-alpha and IL-1beta and the expression of iNOS and MHC class II molecules in rat microglial cells". Journal of Neuroscience Research. 67 (3): 411–21. doi:10.1002/jnr.10102. PMID 11813247.
2. Taniguchi, Y.; Tonaikachi, H.; Shinjo, K. (2006). "Zaprinast, a well-known cyclic guanosine monophosphate-specific phosphodiesterase inhibitor, is an agonist for GPR35". FEBS Letters. 580 (21): 5003–5008. doi:10.1016/j.febslet.2006.08.015. PMID 16934253. S2CID 43142927.
3. Keswani, A. N.; Peyton, K. J.; Durante, W.; Schafer, A. I.; Tulis, D. A. (2009). "The Cyclic GMP Modulators YC-1 and Zaprinast Reduce Vessel Remodeling Through Antiproliferative and Proapoptotic Effects". Journal of Cardiovascular Pharmacology and Therapeutics. 14 (2): 116–124. doi:10.1177/1074248409333266. PMC 2702762. PMID 19342499.
4. Keizo Yuasa; Fumika Mi-Ichi; Tamaki Kobayashi; Masaya Yamanouchi; Jun Kotera; Kiyoshi Kita; Kenji Omori (2005). "PfPDE1, a novel cGMP-specific phosphodiesterase from the human malaria parasite Plasmodium falciparum". Biochem. J. 392 (Pt 1): 221–9. doi:10.1042/BJ20050425. PMC 1317681. PMID 16038615.
5. Yasuhito Taniguchi; Hiroko Tonai-Kachi; Katsuhiro Shinjo (2006). "Zaprinast, a well-known cyclic guanosine monophosphate-specific phosphodiesterase inhibitor, is an agonist for GPR35". FEBS Letters. 580 (21): 5003–5008. doi:10.1016/j.febslet.2006.08.015. PMID 16934253. S2CID 43142927.