Absorptive profile of chlorogenic acid in rats

The objective of this work was to systematically investigate the absorptive profile of chlorogenic acid (CGA) in rats and to increase its intestinal absorption using absorption enhancers. The rat in situ intestinal perfusion technique was used to examine absorptive rate and extent of CGA. In vitro enzymatic drug degradation study was carried out with rat intestinal washings. Various experimental conditions such as different concentrations, extraction purity, and different absorption enhancers such as sodium taurocholate (ST), sodium lauryl sulphate (SLS), carbomer, borneol were examined. Absorption rate constants were determined by the plot of log remaining amount of drug in perfusate vs. time. During the in vitro enzymatic degradation study, no measurable degradation was observed. It was found that CGA could be poorly absorbed by the gastrointestinal tract. The absorptive rate of CGA is independent of the drug concentration. Absorption processes fit first order processes. Extraction of high purity is benefit to the absorption of CGA. Drug absorption extent could be increased via absorption enhancers except SLS. ST appeared to be more effective for enhancing the intestinal absorption of CGA than the other absorption enhancers. In vivo studies were carried out to compare the pharmacokinetic parameters of solutions with and without ST. The order of increasing CGA absorption caused by the enhancers was ST > carbomer > borneol > SLS.