Clindamycin phosphate EP impurity J; Clindamycin phosphate propyl analog; Methyl 7-chloro-6,7,8-trideoxy-6-[[[(2S)-1-methyl-4-propylhexylpyrrolidin-2-carbonyl]amino]-2-O-phosphino-1-thio-L-threonine-α-D-galactopyranose-octapentapentapyrrole; Clindamycin phosphate impurity J