The relatively low solubility of florfenicol (FEC) in water (1.3 mg/mL) limits its use in medicated drinking water systems for treatment of pulmonary disease of swine and poultry. Current formulations use a high volume organic solvent to reach the required FFC concentration of 13.5 mg/mL in an automated proportioner mixing tank system, with practical disadvantages for the users in the field. This invention relates to the effects of complex formation with natural and modified cyclodextrins on the aqueous solubility of FFC and antibiotics of related structure. Furthermore, this invention relates to the effects of polyethylene glycol (PEG-300) as a co-solvent in an FFC-cyclodextrin system to achieve the required FFC dose in the mixing tank system and to avoid high volumes of the organic solvent.
