Guanosine

Guanosine is used as the intermediate of Valaciclovir.
Valacyclovir is a guanine analogue antiviral drug. It is used in the clinical treatment of herpes simplex and herpes zoster infection in sexually transmitted diseases. This product is the precursor of acyclovir. It is absorbed rapidly after oral administration and quickly transformed into acyclovir in the body. Its antiviral effect is played by acyclovir. After acyclovir enters herpes infected cells, it competes with deoxynucleoside for virus thymidine deoxynucleoside kinase or cell kinase, and the drug is phosphorylated into activated acyclic guanosine triphosphate. As the substrate of virus replication, acyclovir competes with deoxyguanine triphosphate for virus DNA polymerase, which inhibits virus DNA synthesis and shows antiviral effect. The antiviral activity of this product in vivo is better than acyclovir, and the treatment index of herpes simplex virus type I and type II is 42.91% and 30.13% higher than acyclovir respectively. It also has high curative effect on varicella zoster virus.