Wells Fargo analyst David Maris said his review of new Drug Master Files added to the FDA database in Q4 leads him to believe Amphastar filed a DMF for the active ingredient to a number of leading respiratory drugs, ipratropium, in November 2017. Amphastar confirmed the filing and that it is related to their pipeline, but would not comment what specific branded product this filing targets, said Maris, who believes the company is working on generic versions of Advair, Flovent, and now possibly Atrovent/Combivent. Maris maintains his Outperform rating on Amphastar shares.