Pharmacokinetics
Taken by mouth, valproate is rapidly and virtually completely absorbed from the gut. When in the bloodstream, 80–90% of the substance are bound to plasma proteins, mainly albumin. Protein binding is saturable: it decreases with increasing valproate concentration, low albumin concentrations, the patients age, additional use of other drugs such as aspirin, as well as liver and kidney impairment. Concentrations in the cerebrospinal fluid and in breast milk are 1 to 10% of blood plasma concentrations.The vast majority of valproate metabolism occurs in the liver. Valproate is known to be metabolized by the cytochrome P450 enzymes CYP2A6, CYP2B6, CYP2C9, and CYP3A5. It is also known to be metabolized by the UDP-glucuronosyltransferase enzymes UGT1A3, UGT1A4, UGT1A6, UGT1A8, UGT1A9, UGT1A10, UGT2B7, and UGT2B15. Some of the known metabolites of valproate by these enzymes and uncharacterized enzymes include (see image):
via glucuronidation (30–50%): valproic acid β-O-glucuronide
via beta oxidation (>40%): 2E-ene-valproic acid, 2Z-ene-valproic acid, 3-hydroxyvalproic acid, 3-oxovalproic acid
via omega oxidation: 5-hydroxyvalproic acid, 2-propyl-glutaric acid
some others: 3E-ene-valproic acid, 3Z-ene-valproic acid, 4-ene-valproic acid, 4-hydroxyvalproic acidAll in all, over 20 metabolites are known.In adult patients taking valproate alone, 30–50% of an administered dose is excreted in urine as the glucuronide conjugate. The other major pathway in the metabolism of valproate is mitochondrial beta oxidation, which typically accounts for over 40% of an administered dose. Typically, less than 20% of an administered dose is eliminated by other oxidative mechanisms. Less than 3% of an administered dose of valproate is excreted unchanged (i.e., as valproate) in urine. Only a small amount is excreted via the faeces.
India, Russia and CIS countries
Valparin Chrono by Sanofi India
Valprol CR by Intas Pharmaceutical (India)
Encorate Chrono by Sun Pharmaceutical (India)
Serven Chrono by Leeven APL Biotech (India)

Brand names of valproate semisodium
Brazil – Depakote by Abbott Laboratories and Torval CR by Torrent do Brasil
Canada – Epival by Abbott Laboratories
Mexico – Epival and Epival ER (extended release) by Abbott Laboratories
United Kingdom – Depakote (for psychiatric conditions) and Epilim (for epilepsy) by Sanofi-Aventis and generics
United States – Depakote and Depakote ER (extended release) by Abbott Laboratories and generics
India – Valance and Valance OD by Abbott Healthcare Pvt Ltd, Divalid ER by Linux laboratories Pvt Ltd, Valex ER by Sigmund Promedica, Dicorate by Sun Pharma
Germany – Ergenyl Chrono by Sanofi-Aventis and generics
Chile – Valcote and Valcote ER by Abbott Laboratories
France and other European countries — Depakote
Peru – Divalprax by AC Farma Laboratories
China – Diprate OD

References
External links
"Valproic acid". Drug Information Portal. U.S. National Library of Medicine. "Valproate sodium". Drug Information Portal. U.S. National Library of Medicine. "Divalproex sodium". Drug Information Portal. U.S. National Library of Medicine.