VALENCIA, Calif. (AP) — Drug developer MannKind Corp. said Monday it will buy a Pfizer Inc. insulin factory in Germany for about $33 million. MannKind said it has an option to issue $30 million worth of its common stock to New York-based Pfizer. The stock could be applied toward the cost of the deal. The factory purchase comes as MannKind prepares to ask the Food and Drug Administration for approval on the inhaled insulin candidate Afresa. MannKind said it plans on keeping half the work force at the German plant.