Evidence map›Paper›PMID 41760874›Full record

ArticlePharmaceutical research2026

A Top-Down Physiologically Based Pharmacokinetic Modeling Approach to Explore Unexpected Bio-inequivalence of Experimental Oral Formulations in Dogs.

Marilyn N Martinez, Viera Lukacova, Shasha Gao, Michael J Myers

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Article in Pharmaceutical research, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Marilyn N MartinezUS Food and Drug Administration, Center for Veterinary Medicine, Office of Generic Animal Drugs, College Park, MD, 20740, USA. marilyn.martinez@fda.hhs.gov.
Viera LukacovaPBPK/Cheminformatics Solutions, Chief Science Officer, Simulations Plus, Inc., Lancaster, California, 93534, USA.
Shasha GaoUS Food and Drug Administration, Center for Veterinary Medicine, Office of New Animal Product Evaluation, College Park, MD, 20740, USA.
Michael J MyersUS Food and Drug Administration, Center for Veterinary Medicine, Office of Applied Sciences, Laurel, MD, 20708, USA.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

purposeA physiologically based pharmacokinetic (PBPK) modeling approach was used to explore potential reasons for the unexpected in vivo/in vitro inconsistencies previously observed in an investigation exploring the comparative oral bioavailability and in vitro dissolution of three experimental treatments. All treatments contained two poorly soluble drugs: ivermectin (IVM) and praziquantel (PRZ). The purpose of that investigation was identification of alternative (non-terminal animal studies) pathways for assessing the bioequivalence (BE) of non-systemically available, locally acting oral formulations.

methodsTreatment differences in gastrointestinal (GI) IVM and PRZ in vivo dissolution and absorption were examined using the GastroPlus PBPK software. Drug models included Michaelis Menten kinetics and canine-specific relative abundances of the primary metabolizing enzyme and efflux transporter. Individual dog predictions were generated using a top-down approach where a double or triple Weibull function was fitted to the previously generated in vivo data (27 dogs × 3 treatments = 81 profiles per drug).

resultsBy examining the predicted treatment differences in in vivo performance, it was possible to exclude several previously proposed reasons for the unexpected poor performance of one of the treatments (e.g., IVM precipitation or intestinal efflux, unintended excipient effects, and rapid dissolution increasing PRZ exposure to enterocyte Cyp3a12) for the unexpected poor performance for one of the treatments.

conclusionsThe top-down approach provided insights into the intestinal location of in vivo dissolution and absorption, eliminating previously proposed causes  and raising alternative possibilities for the observed in vivo/in vitro disparities (indirectly related to the granule diameters of the three treatments). It also helped identify in vitro test procedures worthy of future consideration.

Indexed as

IvermectinModels, BiologicalPraziquantelAdministration, OralAnimalsBiological AvailabilityDogsIntestinal AbsorptionSolubilityTherapeutic EquivalencyIvermectinPraziquantelbioequivalence evaluation of non-systemically absorbed drugsin vivo/in vitro relationshipsivermectinphysiologically based pharmacokinetic modelpraziquantel

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.