Preliminary study of tissue concentrations of penicillin after local administration into the guttural pouches in four healthy horses.

Background Treatment of subclinical carriers of Streptococcus equi subsp. equi with a gelatine-penicillin formulation deposited in the guttural pouch has been empirically proposed, but data on local tissue penicillin concentrations after treatment are lacking. Methods We analysed tissue levels of penicillin after administration into the guttural pouches of four healthy horses. Two horses received local treatment with gelatine-penicillin and two horses received local treatment with an intramammary formulation of penicillin. Tissues were harvested for analysis either 12 or 24 h later. Conclusion Results indicate that local treatment may be effective, but more research on optimal drug formulations in a larger sample size is warranted. [ABSTRACT FROM AUTHOR]