[Effect of crystallinity on the rate of solution of oxytetracycline hydrochloride].

The crystal structure of 2 forms of oxytetracycline hydrochloride prepared with the method of crystallization from various solvents was studied. It was shown that these forms were 2 polymorphic modifications of the antibiotic with different crystal structures. The modification prepared with the method of crystallization from methanol was characterized by better dissolution in water. Its dissolution rate constant was 3 times as higher which makes this crystalline modification of oxytetracycline hydrochloride preferable for preparation of the antibiotic pharmaceutical forms with high bioavailability levels.