Abstract
It has been reported that within a series of esters of erythromycin prepared with low molecular weight aliphatic acids, the propionyl ester gave considerably higher blood levels after oral administration than others in the series as well as higher levels than erythromycin itself. On the basis of findings from past work dealing with dissolution rates of drugs, it seemed reasonable to believe that their absorption under eqivalent conditions of administration was related to their dissolution rate in both gastric fluid and intestinal fluids, particularly since erythromycin and its esters are rapidly destroyed in solution in acidic mediums. The work to be described now consisted of making dissolution rate determinations on erythromycin and some of its esters in fluids simulating gastric and intestinal fluids with respect to hydrogen ion concentration and on examining the relationship between these rates and the results of the clinical work.
