Lopinavir EP Impurity P 

Chemical Name: (2S)-N-[(1R,3S,4S)-1-Benzyl-4-[[2-(2,6-dimethylphenoxy)acetyl]amino]-3-hydroxy-5-phenylpentyl]-3-methyl-2-[2oxotetrahydropyrimidin-1(2H)-yl]butanamide (as per EP); (S)-N-{(2R,4S,5S)-5-[2-(2,6-Dimethylphenoxy)acetamido]-4-hydroxy-1,6-diphenylhexan-2-yl}-3-methyl-2-[2-oxotetrahydropyrimidin-1(2H)-yl]butanamide (as per USP)