Recursive Estimation Method for Predicting Residual Bladder Urine Volumes to Improve Accuracy of Timed Urine Collections
David Afshartous and Richard Preston
Problem
Clinical testing of new drugs often includes analysis of a series of urine samples to determine the proportion of a test dose of a drug cleared by the kidney as a function of time. Unfortunately, precision of this method is limited by not knowing the residual amount of urine in the bladder, which introduces significant systematic uncertainty to the estimated amount of substance cleared by the kidney. What is needed is a method to account for this residual amount in urine collection.
Solution
The invention is an algorithm for determining residual volume of urine not emptied during voiding. The algorithm relies on conservation of mass and conservation of concentration principles using production of referenced substance that is known to be produced at constant rate. In particular, the concentration of creatinine can be used as a reference.
Competitive Advantage
The invention provides a unique approach to high precision, low cost method to calculate the residual amount of urine in a bladder. We expect the FDA will require pharmaceutical companies to use this method in clinical trials.
Applications
(1)Clinical testing of new drugs.
(2)Clinical pharmacokinetic studies.
(3)Clinical research studies of electrolyte excretion.
(4)Renal clearance studies of compounds and substances.
(5)Improved accuracy of determinations of renal function
Patent Status
International patent application entitled "RECURSIVE ESTIMATION METHOD AND SYSTEM FOR PREDICTING RESIDUAL BLADDER URINE VOLUMES" was filed on February 13, 2009.
Licensing Opportunity
We are seeking a commercialization partner with capabilities in product development, sales, and marketing. An exclusive worldwide license is available.
About the Inventors
Dr. Richard A. Preston is Professor of Medicine, Chief of the Division of Clinical Pharmacology, and Director of the Clinical Pharmacology Phase I Research Center at the Miller School of Medicine, University of Miami. Dr Preston is Board Certified in Internal Medicine, Nephrology, and Clinical Pharmacology. Dr. Preston has more than 100 scientific publications in hypertension, renal disease, and clinical pharmacology and has been principal investigator of more than 70 clinical research studies. He serves on the editorial board or as referee for 14 scientific journals.
David Afshartous, Ph.D. is a Research Assistant Professor in the Division of Clinical Pharmacology, Miller School of Medicine, University of Miami. He received his Ph.D. in mathematics from UCLA in 1997. He then worked for Lucent Technologies Bell Labs before joining the University of Miami in 2002. His main research area concerns statistical methods for analyzing repeated measurements over time, and he has published his work in peer reviewed journals in the areas of statistics, operations research, and medicine.
Selected References
Afshartous, David, and Preston, R.A. (2008). "A Recursive estimation method for predicting residual bladder urine volumes to improve accuracy of timed urine collections," Statistical Methods for Medical Research, in press.
Preston, R.A., Afshartous, D., Alonso, A.B. (2008). "Effects of Selective versus Nonselective Cyclooxygenase Inhibition on Dynamic Renal Potassium Excretion: A Randomized Trial," Clinical Pharmacology and Therapeutics , in press.
