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Published on: March 28, 2017
Estimates of Drug Metabolism Using Drug Excretion Concentrations
Agnes Cua1, Kevin Krock1, Richard Thomas1
1Precision Diagnostics LLC, San Diego CA, USA.
Abstract:
We propose that quantitative urine drug concentrations from LC-MS/MS measurements can be used to estimate zero and first order pharmacokinetics of the drugs oxycodone, hydrocodone, buprenorphine, methadone, and fentanyl. We observed the ratio of metabolite to parent drug could be used for this estimate. As the amount of observed parent drug increased, the metabolic ratio decreased, indicating a shift from first order to zero order metabolism. After making assumptions of bioavailability, percent of drug excreted into urine, we developed estimates of the saturating dosages for these drugs.
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