IBSA owns a patent directed to pharmaceutical formulations for thyroid hormones that enable a safe and stable oral administration. IBSA listed in the Orange Book the patent for Tirosint ®, a soft gel capsule formulation containing the active ingredient levothyroxine sodium. Teva filed an abbreviated new drug application to market a generic version of Tirosint ®, and IBSA responded by filing a lawsuit for patent infringement against Teva.