Spironolactone EP Impurity A

Chemical Name: S-[(2′R)-3,5′-dioxo-5′H-spiro[androst-4-ene-17,2′-furan]-7α-yl] ethanethioate (as per EP); (2′R)-7α-(Acetylthio)-5′H-spiro[androst-4-ene-17,2′-furan]-3,5′-dione (as per USP)