Chemical Name: (2Ξ,3Ξ)-3-(4-fluorobenzoyl)-2-(2-methylpropanoyl)-N,3-diphenyloxirane-2-carboxamide (D1) and (1Ξ,2Ξ,4Ξ,5Ξ)-4-(4-fluorophenyl)-2,4-dihydroxy-N,5-diphenyl-2-(propan-2-yl)-3,6-dioxabicyclo[3.1.0]hexane-1-carboxamide (D2) (as per EP); Epoxide Impurity, 3-(4-Fluorobenzoyl)-2-isobutyryl-N,3-diphenyloxirane-2-carboxamide (as per USP)

Synonym: Atorvastatin USP Related Compound D ; Atorvastatin Diketo Epoxide ; Atorvastatin Degradation Product – ATV-FXA1