Abstract: AimTo prepare clarithromycin emulsion and investigate its pharmacokinetics in rats. And to do irritation test of the emulsion. MethodsHigh pressure homogenization method was used to prepare clarithromycin emulsion, and the Nicomp380 machine was used to test the mean particle size and zeta-potential of clarithromycin emulsion. Irritation of emulsion was also evaluated compared with the positive control of clarithromycin solution using rat paw lick test and rabbit ear vein irritation test. Microbiological assay method was used for determining the drug concentration in plasma. Pharmacokinetics of two dosage forms in rats was also studied. ResultsThe mean particle size and zeta potential of clarithromycin emulsion were 156 nm and -31.8 mV, respectively. The emulsion was stable during the storage time at 4 ℃ for 6 month. The pain caused by emulsion reduced significantly compared with that of clarithromycin solution based on the results of rat paw lick test and rabbit ear vein test. The drug concentration-time curves of clarithromycin emulsion and clarithromycin solution were similar and could be described by two compartment model. AUC0-t of clarithromycin emulsion and clarithromycin solution were (66.76±16.34) and (59.00±11.20) μg·h·mL^-1, respectively. ConclusionStable emulsion could be prepared using high pressure homogenization method, and irritation caused by iv injection could be reduced significantly by using clarithromycin emulsion.