ALLEGAN, MI (WHTC) - Perrigo continues its patent challenges. The Allegan-based drug maker was given the judicial OK yesterday to make and sell the generic form of the overactive bladder medication Sanctura XR that has annual sales of around 54 million dollars. Perrigo is also seeking approval through the courts to market a generic version of the testosterone topical solution Axiron, which earns about 229 million dollars yearly.