THE PHARMACOKINETICS OF 2 ERYTHROMYCIN ESTERS IN PLASMA AND IN SALIVA FOLLOWING ORAL-ADMINISTRATION IN HUMANS

Abstract

An improved highly sensitive fluorimetric method was employed to measure plasma and saliva levels of erythromycin propionate and stearate in 8 healthy volunteers following a single oral dose of 7.5 mg/kg. The plasma curves exhibited a mean half-life of 5.22 .+-. 0.86 h-1 for the propionate and 2.97 .+-. 0.22 h-1 for the stearate. Peak levels were reached at the 2nd h (4.07 .+-. 0.29 .mu.g/ml for the propionate; 2.15 .+-. 0.14 .mu.g/ml for the stearate). The area under the total plasma concentration curve was about 3-fold higher in the case of propionate. The concentration in saliva was about 20% of the corresponding concentration in plasma for the propionate and about 25% for the stearate. A significant positive correlation was observed between plasma and saliva levels for both macrolides.