HPLC estimation of iothalamate to measure glomerular filtration rate in humans

Iltaf Shah, James Barker, Declan P. Naughton, Stephen J. Barton, Syed Salman Ashraf

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Glomerular filtration rate (GFR) is usually determined by estimation of iothalamate (IOT) clearance. We have developed and validated an accurate and robust method for the analysis of IOT in human plasma and urine. The mobile phase consisted of methanol and 50mM sodium phosphate (10:90; v/v). Flow rate was 1.2mL/min on a C18 reverse phase column, Synergi-hydro (250×4.6mm) 4μm 80Å, with an ultraviolet detector set to 254nm. Acetonitrile was used for the deproteination and extraction of IOT from human plasma and urine. Precision and accuracy were within 15% for IOT in both plasma and urine. The recoveries of IOT in urine and plasma ranged between 93.14% and 114.74 and 96.04-118.38%, respectively. The linear range for urine and plasma assays were 25-1500 and 1-150μg/mL respectively. The lower limits of detection were 0.5μg/mL for both urine and plasma, with no interference from plasma and urine matices. This method has been fully validated according to FDA guidelines and the new HPLC assay has been applied to a new formulation of IOT (Conray™ 43), to calculate GFR in healthy volunteers. The new method is simple, less expensive and it would be instrumental in future clinical and pharmacokinetic studies of iothalamate in kidney patients.

Original languageBritish English
Article number80
JournalChemistry Central Journal
Issue number1
StatePublished - 12 Dec 2016


  • GFR
  • Glomerular filtration rate
  • HPLC
  • Human urine and plasma
  • Iothalamate
  • Iothalamic acid


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