Hydroxyquatrimycin, 4-epi-Oxytetracycline, [4R-(4alpha,4abeta,5beta,5abeta,6alpha,12abeta)]-4-(Dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,5,6,10,12,12a-hexahydroxy-6-methyl-1,11-dioxo-2-naphthacenecarboxamide, Oxytetracycline Hydrochloride Impurity A, Oxytetracycline Impurity A