Tetracycline is an organic compound with a molecular formula of C22H24N2O8. Both itself and its salts are yellow or pale yellow crystals. They are extremely stable in dry state. Except for chlortetracycline, other aqueous solutions of tetracycline are quite stable. The tetracycline family is soluble in dilute acid, dilute alkali, etc., slightly soluble in water and lower alcohol, but insoluble in ether and petroleum ether. Tetracycline antibiotics mainly include chlortetracycline, oxytetracycline, and tetracycline. Tetracycline antibiotics share a common chemical structural parent. Both chlortetracycline and oxytetracycline are derivatives of tetracycline, the former is chlorotetracycline (chlorotetracycline), the latter is oxytetracycline (oxyeracyein), tetracyclines are acid-base amphoteric compounds.

Tetracycline has a molecular formula of C22H24N2O8 and a molecular weight of 444.45. It is a broad-spectrum Antibiotic. Yellow crystal, bitter taste, melting point 170~175℃ (decomposition). Slightly soluble in water, soluble in ethanol and acetone, stable in air, but easy to absorb moisture, discolored by strong sunlight.

Tetracycline hydrochloride is a broad-spectrum antibiotic, most of the GRAM-positive and negative bacteria have inhibitory effect, high concentration has bactericidal effect, and can inhibit rickettsia, trachomatis virus, Gram-negative bacilli, good effect. Its mechanism of action is mainly to prevent the binding of amacyl group and ribonucleosome, prevent the growth of peptide chain and protein synthesis, so as to inhibit the growth of bacteria, and also have bactericidal effect at high concentration.