Objective  To prolong the maintenance time of the effective blood concentration of the drug, generate a sustainable and stable bacteriostatic action, and avoid embryotoxicity and immunosuppression in multi-dose continuous use of florfenicol.

Method  The test used hardened oil, polyethylene glycol and glyceride as auxiliary materials. The florfenicol sustained-release granules were prepared by centrifugal spray drying granulation method, and the content of florfenicol was determined by high performance liquid chromatography (HPLC). Using release characteristics of the drug in different media (pH 1.2 hydrochloric acid buffer, pH 4.3 acetate buffer and pH 6.8 phosphate buffer) as indicators, the dissolution tests of florfenicol powder and self-made florfenicol sustained-release granules were carried out to investigate their in vitro release performances.

Result  The percentages of florfenicol actual contents in indicated contents of florfenicol sustained-release granules prepared in four batches were 99.19%, 100.01%, 97.45% and 100.72%, and the relative standard deviations (RSD) were 0.82%, 0.86%, 0.77% and 0.24% respectively. The florfenicol powder was completely released within 0.25 h. The self-made florfenicol sustained-release granules were substantially not released in simulated gastric fluid environment (pH 1.2 hydrochloric acid buffer), and released slowly under simulated intestinal fluid environment (pH 4.3 acetate buffer and pH 6.8 phosphate buffer) with the release amount of over 95% within 5 h.

Conclusion  The drug in self-made florfenicol sustained-release granules is homogeneous distributed, and the granules conform to China veterinary pharmacopoeia. Compared with florfenicol powder, florfenicol sustained-release granules show good acid resistance and in vitro sustained-release performance, which provides a reference for subsequent clinical trial research and clinical use of drugs.