Doxycycline for Injection, USP is a sterile, lyophilized powder prepared from a solution of doxycycline hyclate, ascorbic acid and mannitol in Water for Injection. Doxycycline hyclate is a broad spectrum antibiotic derived from oxytetracycline. It is meant for INTRAVENOUS use only after reconstitution. Doxycycline hyclate is a yellowish crystalline powder which is chemically designated 4-(Dimethylamino)-1,4,4a,5,5a,6,11, 12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methyl-1,11-de monohydrochloride, compound with ethyl alcohol (2:1), monohydrate. It has the following structural formula:

(C22H24N2 O8 • HCl)2 • C2H6O • H2O 1025.89

Doxycycline hyclate is soluble in water and chars at 201°C without melting. The base doxycycline has a high degree of lipid solubility and a low affinity for calcium binding. It is highly stable in normal human serum.

Each 100 mg vial contains: Doxycycline hyclate equivalent to 100 mg doxycycline; ascorbic acid 480 mg; mannitol 300 mg. pH of the reconstituted solution (10 mg/mL) is between 1.8 and 3.3.

Each 200 mg vial contains: Doxycycline hyclate equivalent to doxycycline 200 mg; ascorbic acid 960 mg; mannitol 600 mg. pH of the reconstituted solution (10 mg/mL) is between 1.8 and 3.3.^[1]

Adapted from the FDA Package Insert.