Mechanisms of action
The most commonly associated mechanism associated with ledipasvir/sofosbuvir is the hyperphosphorylation of NS5A, a viral polymerase important in proper viral assembly and interferes with proper liver metabolism. Ledipasvir/sofosbuvir inhibits the proper viral assembly by re-positioning NS5As sub-cellular localization.NS5B, a viral polymerase that can initiate RNA synthesis de novo, is also allosterically inhibited by ledipasvir/sofosbuvir.NS5A and NS5B inhibitors in combination have a synergistic effect. Pharmacokinetics
Sofosbuvir is absorbed fast in the plasma with a peak concentration (Cmax) at 0.8 to 1 hour after the administered dosage and undergoes extra hepatic metabolism with 61 to 65% bound to human plasma proteins. It is then predominantly converted to the inactive phosphate free circulating metabolite GS-331007 (eliminated 76% through renal passive filtration) which has a median peak plasma concentration at 3.5 to 4 hours after the medication is ingested. Sofosbuvir does not appear to be affected by different levels of macronutrients when compared with fasting states.Ledipasvir has a maximum concentration at 4 to 4.5 hours after ingestion and is not affected by macronutrients. It is more than 98% protein bound and is predominantly eliminated fecally, with minimal metabolism in the liver. Elimination
The median terminal half life after a dosage of ledipasvir/sofosbuvir for 90 mg of [14C]-Ledipasvir is 47 hours; for 400 mg of [14C]-Sofosbuvir it is 0.5 hours (after the initial distribution of medication in body tissue) and 27 hours (the eventual excretion of the medication).
Note: The maximum concentration is 32% higher in healthy individuals than those infected with Hepatitis C.
Note: The maximum concentration is 24% higher in healthy individuals than those infected with Hepatitis C.

Blood detection
An analytical method based on LC tandem MS has been developed for the simultaneous extraction and determination of ledipasvir/sofosbuvir in human plasma using antiviral daclatasvir as an internal standard. Average extraction recoveries for sofosbuvir and ledipasvir were 91.61% and 88.93% respectively. Society and culture
One manufacturer is Gilead Sciences. References
External links
"Ledipasvir mixture with sofosbuvir". Drug Information Portal. U.S. National Library of Medicine.