MUMBAI: Ranbaxy Laboratories has entered into a strategic partnership with the U.S.-based Invagen Pharmaceuticals for marketing Zonisamide Capsules, which are used for the treatment of epilepsy, in the U.S. market. Under the agreement products would be developed and submitted for approval to the USFDA. Ranbaxy Pharmaceuticals Inc would market the products under the company's label, says a release.