Meda Pharmaceuticals Inc., of Goteborg, Sweden, and Cipla Ltd., of Mumbai, India, said they sued Apotex Inc., of Toronto, along with U.S. arm Apotex Corp., in Federal District Court in Delaware to enforce the Orange Book-listed patents covering Dymista (azelastine HCl/fluticasone propionate) nasal spray, in response to Apotex's submission to the FDA of an abbreviated new drug application and accompanying paragraph IV certification, seeking approval to market a generic version of Meda's Dymista prior to expiration of the Dymista patents.