Mass Balance Recovery With Paxalisib: Clinical AME Data

Pharmaron poster summary highlighting a single-dose study on mass balance recovery, metabolism, and excretion of [14C]-Paxalisib in healthy males.

Poster Authors:

Jessica Richardson¹ ; Eleanor Barton¹; Claire Broughton¹; Ray Cooke¹; Stephen English², David Neville¹; Iain Shaw³; Phil Evans³; Jeremy Simpson⁴; John Friend⁴

¹Pharmaron UK.

²Pharmaron (Germantown) Lab Services, Inc.

³Quotient Sciences

⁴Kazia Therapeutics

Mass balance recovery anchors confidence in human ADME packages. This overview turns the Paxalisib clinical AME metabolite study into practical guidance for planning clean recovery, clear metabolite IDs, and fit-for-purpose analytics. Register to download the poster and get figures, chromatograms, and exact settings you can reuse.

Why mass balance recovery matters in first-in-human AME

Recovery tells you whether your collection window, matrices, and analytics captured the fate of the dose. Good recovery supports decisions on routes of elimination, major metabolites, and follow-up safety work. The Paxalisib program paired a radiolabeled dose with pooled plasma, urine, and feces to profile drug-related material across matrices.

Capabilities

Knowledge Center

Human AME with Radiolabelled Compounds

Mass Balance with Radiolabelled Compounds

Mass Balance by AMS

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How the Paxalisib AME study was set up

A single oral [¹⁴C] dose was given to a small cohort of healthy adults. Plasma, urine, and feces were pooled across defined time ranges to build representative profiles. Very low circulating radioactivity in plasma required high-sensitivity AMS for metabolite quantification while urine and feces used scintillation counting. This mix of technologies balanced sensitivity, throughput, and matrix load.

What the metabolite work reveals about Paxalisib

Multiple metabolites were observed across matrices, with a focused set dominating circulation. Three radiolabeled components accounted for most of the plasma drug-related material. Unchanged Paxalisib was confirmed in urine and was the major component in feces with about one quarter of the dose. The main human biotransformations were hydrolysis or oxidation on the dimethylmorpholine ring which maps to a clear pathway figure in the poster.

Design choices that improve mass balance recovery

Use time-pooled sampling to smooth subject variability. Keep subjects on study to a recovery plateau. Match analytics to matrix and signal level, reserving AMS for very low plasma radioactivity. Co-locating GMP radiolabel manufacture with the dosing clinic simplifies logistics and helps hit recovery goals without delays. The poster shows each step and the chromatographic conditions used.

Why download the poster

See pooled-matrix strategies that support strong recovery
Review plasma and feces radiochromatograms with annotated IDs
Get the proposed biotransformation map for Paxalisib
Lift your own recovery plan with practical collection and analysis notes

Download the poster now.