# FDA Approves Generic Glycerol Phenylbutyrate; Zydus Pharmaceuticals Entry Expected to Intensify Competition The FDA has granted approval to Zydus Pharmaceuticals USA Inc. for a generic formulation of glycerol phenylbutyrate, an oral medication used to treat urea cycle disorders, potentially reducing treatment costs for patients while pressuring branded competitors' market share. The approval of ANDA220568 signals growing generic penetration in the specialized hyperammonemia treatment market, where pricing and access have been key concerns for healthcare providers and patients.