57877-50-6 64858-59-9 Doxycycline polymethaphosphate sodium complex Doxycycline sodium polyphosphate Metaphosphoric acid (H6O18P6), disodium salt, compd. with (4S-(4alpha,4aalpha,5alpha,5aalpha,6alpha,12aalpha))-4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methyl-1,11-dioxo-2-naphthacenecarboxamide (4:1) Metaphosphoric acid (H6P6O18), disodium salt, compd, with (4S-(4alpha,4aalpha,5alpha,5aalpha,6alpha,12aalpha))-4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methyl-11-dioxo-2-naphthacenecarboxamide (1:4)