Current challenges and future perspectives in oral absorption research: An opinion of the UNGAP network

Zahari Vinarov, Bertil Abrahamsson, Per Artursson, Hannah Batchelor, Philippe Berben, Andreas Bernkop-Schnürch, James Butler, Jens Ceulemans, Nigel Davies, Didier Dupont, Gøril Eide Flaten, Nikoletta Fotaki, Brendan T Griffin, Vincent Jannin, Janneke Keemink, Filippos Kesisoglou, Mirko Koziolek, Martin Kuentz, Alan Mackie, Antonio J Meléndez MartinezMark McAllister, Anette Müllertz, Caitriona M O'Driscoll, Neil Parrott, Jadwiga Paszkowska, Petr Pavek, Christopher J H Porter, Christos Reppas, Cordula Stillhart, Kiyohiko Sugano, Elena Toader, Kateřina Valentová, Maria Vertzoni, Saskia De Wildt, Clive G Wilson, Patrick Augustijns

Research output: Contribution to journalReview articlepeer-review

82 Citations (SciVal)


Although oral drug delivery is the preferred administration route and has been used for centuries, modern drug discovery and development pipelines challenge conventional formulation approaches and highlight the insufficient mechanistic understanding of processes critical to oral drug absorption. This review presents the opinion of UNGAP scientists on four key themes across the oral absorption landscape: (1) specific patient populations, (2) regional differences in the gastrointestinal tract, (3) advanced formulations and (4) food-drug interactions. The differences of oral absorption in pediatric and geriatric populations, the specific issues in colonic absorption, the formulation approaches for poorly water-soluble (small molecules) and poorly permeable (peptides, RNA etc.) drugs, as well as the vast realm of food effects, are some of the topics discussed in detail. The identified controversies and gaps in the current understanding of gastrointestinal absorption-related processes are used to create a roadmap for the future of oral drug absorption research.

Original languageEnglish
Pages (from-to)289-331
Number of pages43
JournalAdvanced Drug Delivery Reviews
Early online date18 Feb 2021
Publication statusPublished - 30 Apr 2021

Bibliographical note

Funding Information:
This article is based upon work from COST Action UNGAP (CA16205), supported by COST (European Cooperation in Science and Technology), funded by the Horizon 2020 Framework Programme of the European Union. The support of Dagmara Hoc, Marcela Wiater, Dorota Haznar Garbacz and Grzegorz Garbacz in the edition of a part of the article is kindly acknowledged. The work has been partially financed by Polish National Centre for Research and Development (POIR.01.02.00-00-0011/17). Supported by Ministry of Education, Youth and Sports of the Czech Republic, No. LTC19039 and LTC18003 (COST Actions UNGAP and NutRedOx) and by the Czech Science Foundation, grant number 18-00132S.

Publisher Copyright:
© 2021 The Authors


  • Advanced formulations
  • Amorphous solid dispersions
  • Food-drug interactions
  • In vitro tools
  • Lipid-based formulations
  • Microbiome
  • PBPK modeling
  • Regional differences
  • Specific patient populations

ASJC Scopus subject areas

  • Pharmaceutical Science


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