dicalcium;(4S,4aR,5S,5aR,6R,12aR)-2-carbamoyl-4-(dimethylamino)-10-hydroxy-6-methyl-3,12-dioxo-4a,5,5a,6-tetrahydro-4H-tetracene-1,5,11,12a-tetrolate
Doxycycline Calcium is the calcium salt form of doxycycline exhibiting antimicrobial activity.  Doxycycline blocks binding of aminoacyl-tRNA to the mRNA-ribosome complex, thereby inhibiting protein synthesis.  In addition, this agent has exhibited inhibition of collagenase activity. (NCI)