On June 25, 2010, Bayer sued Teva for falsely claiming that Gianvi, Teva's Generic of Yaz, was "stabilized by betadex as a clathrate." The lawsuit stems from Bayer's US patent, 5798338, on the binding and preservative agents that were not in fact present in Gianvi. "In the preparation of such low-dosed dosage forms, strong fluctuations of the active ingredient concentrations in the dosage units occur almost unavoidably (inadequate content uniformity), which manifest themselves more strongly, the smaller the amount of the active ingredient. It has now been found that the drawbacks that are observed especially in the preparation and storage of dosage forms which contain low-dosed steroidal sex hormones can be avoided, at least to a large extent, if dosage forms are prepared that contain powdery cyclodextrin clathrates of these active ingredients." The settlement of the lawsuit resulted in Teva changing its product marketing to remove the claim that it used the same ingredients as Yaz. Bayer's patent is on a method specifically designed to prevent oxidative degradation of the estrogen.