title: The concentration-dependent disposition and kinetics of inulin.
abstract: The disposition of inulin was studied in 30 healthy male and 10 healthy female volunteers, and 10 patients with stable chronic renal failure (mean creatinine clearance 45 ml.min-1) following intravenous infusion of 70 mg.kg-1 over 5 min. Plasma concentrations fell rapidly initially but the rate of decline decreased continuously over 8 h and a linear terminal elimination phase could not be identified. Inulin was excreted rapidly by the subjects with normal renal function and 97.3% of the dose was recovered in the urine in 8 h. There was a progressive highly significant fall in the renal clearance of inulin after 2 h as plasma concentrations fell below about 150 mg.l-1. Six to 8 h after administration the clearance was less than 50% of the initial value in the healthy volunteers and the corresponding fall in the renal patients was 33%. The concentration-dependent renal clearance of inulin was confirmed in "step-up" and "step-down" constant infusion studies in which clearances were measured at mean plasma concentrations ranging from 35.2 to 186.7 mg.l-1. These studies virtually excluded time, changes in posture and urine flow rate as important factors. There was no statistically significant fall in clearance during the first 2 h and kinetic analysis was based on data obtained over this time.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: University Department of Clinical Pharmacology, Royal Infirmary, Edinburgh, Scotland, UK.
authors.forename: L F
authors.initials: LF
authors.lastname: Prescott
authors.forename: J A
authors.initials: JA
authors.lastname: McAuslane
authors.forename: S
authors.initials: S
authors.lastname: Freestone
mesh_terms: D000328:Adult; D003404:Creatinine / Q000097:blood; D005260:Female; D006207:Half-Life; D006801:Humans; D007262:Infusions, Intravenous; D007444:Inulin / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics* / Q000652:urine; D007676:Kidney Failure, Chronic / Q000188:drug therapy / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D012079:Renal Circulation; D013223:Statistics as Topic
chemical_list: D007444:Inulin; D003404:Creatinine