Temperature matters when determining pH levels. Whether that level should be measured at a standard room temperature or refrigerated matters even more, at least in Actelion Ltd.’s infringement litigation against Mylan Inc. According to Johnson & Johnson’s Actelion, the pH level in epoprostenol, the key ingredient in its hypertension drug Veletri, should be measured at a refrigerated temperature when it comes to Mylan’s generic formulation.