Tetracycline hydrochloride is a salt prepared from tetracycline taking advantage of the basic dimethylamino group which protonates and readily forms the salt in hydrochloric acid solutions. The hydrochloride is the preferred formulation for pharmaceutical applications. Tetracycline hydrochloride has broad spectrum antibacterial and antiprotozoan activity and acts by binding to the 30S and 50S ribosomal sub-units blocking protein synthesis.