Valacyclovir hydrochloride Chemische Eigenschaften,Einsatz,Produktion Methoden
R-S?tze Betriebsanweisung:
R36/37/38:Reizt die Augen, die Atmungsorgane und die Haut.
S-S?tze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S36:DE: Bei der Arbeit geeignete Schutzkleidung tragen.
Beschreibung
Valacyclovir hydrochloride, an orally active L-valyl ester of the potent antiviral agent aciclovir, was launched in 1995 in the United Kingdom for the treatment of herpes simplex virus (HSV) infections of the skin and mucous membranes, including initial and recurrent genital herpes. As a prodrug, valaciclovir has an improved pharmacokinetic profile to aciclovir. It is rapidly absorbed after oral administration and extensively converted to aciclovir via first-pass metabolism to achieve plasma levels of aciclovir comparable to those seen with aciclovir via i.v. route. Valacyclovir is then activated selectively in virus-infected cells by viral thymidine kinase to form aciclovir triphosphate in a stepwise fashion. This active species inhibits viral DNA polymerase via irreversible binding to the active site of the enzyme. Once aciclovir is incorporated into the elongating viral DNA, it terminates replication of the viral DNA strand, an antiviral mechanism unique to aciclovir. Valacyclovir is reportedly in clinical trials for the suppression of cytomegalovirus infection and disease in renal transplant patients.
Chemische Eigenschaften
White Crystalline Powder
Verwenden
Acyclovir (A192400) impurity. The L-Valine ester prodrug of Acyclovir.
Allgemeine Beschreibung
Valacyclovir (Valtrex) is the hydrochloride salt of the Lvalylester of acyclovir. The compound is a water-solublecrystalline solid, and it is a prodrug intended to increase thebioavailability of acyclovir by increasing lipophilicity.Valacyclovir is hydrolyzed rapidly and almost completely toacyclovir following oral administration.
Valacyclovir has been approved for the treatment of herpeszoster (shingles) in immunocompromised patients. Theside effect profile observed in valacyclovir is comparablewith bioequivalent doses of acyclovir.
Pharmakokinetik
The binding of valacyclovir to human plasma proteins ranges between 13.5 to 17.9%. The plasma elimination half-life of acyclovir is 2.5 to 3.3 hours. The bioavailability of valacyclovir hydrochloride is 54%, compared to approximately 20% for oral acyclovir, and it is as effective as acyclovir in decreasing the duration of pain associated with posttherapeutic neuralgia and episodes of genital lesion healing.
Nebenwirkungen
The adverse effects are similar to acyclovir, which include nausea, headache, vomiting, constipation, and anorexia.
Valacyclovir hydrochloride Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
