Iodipamide kinetics: capacity-limited biliary excretion with simultaneous pseudo-first-order renal excretion.

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Lin SK, Moss AA, Riegelman S

Iodipamide kinetics: capacity-limited biliary excretion with simultaneous pseudo-first-order renal excretion.

J Pharm Sci. 1977 Dec;66(12):1670-4.

PubMed ID

925927 [ View in PubMed

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Abstract

Iodipamide was infused into three dogs with bile fistulas to achieve various steady-state blood levels. When using ultracentrifugation techniques, iodipamide was found to be highly bound to plasma protein. The total blood clearance was low relative to hepatic blood flow. For either the whole blood concentration or the unbound concentration of iodipamide, the biliary excretion was shown to be capacity limited with a transport maximum, Tm, of approximately 1.0mumole/kg/min. The steady-state renal excretion rate, plotted against the whole blood concentration of iodipamide, resulted in a concave ascending curve, which could lead to the false conclusion that iodipamide was undergoing active renal tubular reabsorption. However, when corrected for plasma protein binding, a linear relationship was obtained, suggesting that the renal excretion of iodipamide is a pseudo-first-order process. The Michaelis-Menten parameters for the extrarenal elimination, when calculated using the whole blood concentration of iodipamide, led to a similar discrepancy compared to the parameter estimates obtained from biliary excretion rate data. This discrepancy can be eliminated when one uses the unbound concentration of iodipamide in the parameter estimates.

DrugBank Data that Cites this Article

Drugs

Iodipamide

Drug Carriers

Drug	Carrier	Kind	Organism	Pharmacological Action	Actions
Iodipamide	Serum albumin	Protein	Humans	Unknown	Binder	Details