Abstract: The invention relates to a process for the preparation of an oxytetracycline-calcium silicate complex salt from fermentation broth.By the process according to the invention the valuable antibiotic oxytetracycline may be separated from the fermentation broth in an easy manner. The complex obtained according to (a) contains up to 50% of antibiotic and is suitable for the processing in the pharmaceutical industry while the product according to (b) contains 10 to 20% of antibiotic and may be used as fodder additive directly.

Abstract: The invention relates to a new process for the preparation of easy-flowing (flowable) oxytetracyclin hydrochloride. According to the process of the invention, the crude, dry or filter-wet oxytetracyclin hydrochloride consisting of needle-shaped crystals is boiled with an organic solvent forming an azeotropic mixture with water, optionally a part of the solvent is distilled off in a form of an azeotropic mixture, then the mixture is cooled and the precipitated oxytetracyclin hydrochloride consisting of spherical crystals is separated and dried.Oxytetracyclin hydrochloride exists in two various crystal forms, the one of which is needle-shaped, while the other one consists of orthorhombic sheets. The crystals of this latter form are capable of forming spherical particles by coalescence. The crystal form consisting of spherical particles is much more useful for the pharmaceutical industry.