ABSTRACT
Numerous studies have been conducted in which urinary excretion of polyvinylpyrrolidone (PVP) of various grades has been measured, the most informative being those where the PVP has been given intravenously. As with the absorption studies, many have been carried out using the PVP simply as a tool to investigate pore size in membranes, and in particular in glomerular membranes. Excretion of PVP in humans is more rapid and more complete with lower molecular weight material. This has been clearly shown in two studies by Brautigam and Gleiss, in which urinary PVP was estimated by chemical analysis. Although intravenously administered PVP was once widely used as a plasma expander, few studies have been conducted in which urinary excretion has been quantitated. This relates mainly to the difficulty of accurately estimating PVP in the urine without the aid of radioactive markers, and the obvious ethical problems of imposing such a hazard on a patient for purely research purposes.
