[(1R,2R)-1-[(2S,5S,11S,14S,17S,20S,23R,26S,29S,32S)-5-ethyl-1,7,10,16,20,23,25,28,31-nonamethyl-11,17,26,29-tetrakis(2-methylpropyl)-3,6,9,12,15,18,21,24,27,30,33-undecaoxo-14,32-di(propan-2-yl)-1,4,7,10,13,16,19,22,25,28,31-undecazacyclotritriacont-2-yl]-2-methyl-4-oxobutyl] acetate; Cyclosporin Impurity A; (1R,2R)-1-((2S,5S,11S,14S,17S,20S,23R,26S,29S,32S)-5-ethyl-11,17,26,29-tetraisobutyl-14,32-diisopropyl-1,7,10,16,20,23,25,28,31-nonamethyl-3,6,9,12,15,18,21,24,27,30,33-undecaoxo-1,4,7,10,13,16,19,22,25,28,31-undecaazacyclotritriacontan-2-yl)-2-methyl-4-oxobutyl acetate; 6-[(3R,4R)-3-(Acetyloxy)-N,4-dimethyl-6-oxo-L-norleucine] Cyclosporin A