Peritoneal kinetics of different drugs

In patients on peritoneal dialysis drug movement across the peritoneum depends on the physiology of the peritoneal membrane, the physiochemical properties of the drug, the dialysis regimen and the basic pharmacokinetic properties of the particular pharmacon. Besides the low dialysate flow rate in continuous ambulatory peritoneal dialysis (CAPD), the latter point-drug kinetics-is thought to be of major importance for the influence of CAPD on drug kinetics. The eliminative potency of CAPD for drugs is limited due to the low dialysate outflow rate, an unfavorable ratio of the dialysate to the body volumes of distribution, the usually low ratio of the peritoneal to body clearance and the effect of drug protein binding. With intraperitoneal application, the drug appears rapidly in the circulation. This again results from the large differences in the volumes of the body to the peritoneal compartments, leading to a high concentration gradient across the peritoneal membrane. Thus a rapid disappearance of a pharmacon from the peritoneal cavity following intraperitoneal application combined with an insufficient drug elimination by CAPD may be explained by basic pharmacokinetic considerations. Unidirectional peritoneal transport of a particular drug has so far not been demonstrated.