dicalcium;(5R,5aR,6S,6aR,7S,10aS)-9-carbamoyl-7-(dimethylamino)-6-hydroxy-5-methyl-10,12-dioxo-5a,6,6a,7-tetrahydro-5H-tetracene-1,8,10a,11-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)