The In Vivo Effect of Transcellular Permeation Enhancers on the Intestinal Permeability of Two Peptide Drugs Enalaprilat and Hexarelin.

Dahlgren D, Sjöblom M, Hedeland M, Lennernäs H

Pharmaceutics26 Jan 2020Cited by 16 (Europe PMC)

PMID31991924PMCIDPMC7076382DOI10.3390/pharmaceutics12020099PepBankPUB-31991924

Summary

Permeation enhancers like sodium dodecyl sulfate (SDS) and caprate increase the intestinal permeability of small model peptide compounds, such as enalaprilat (349 Da). However, their effects remain to be investigated for larger low-permeability peptide drugs, such as hexarelin (887 Da). The objective of this single-pass perfusion study in rat was to investigate the effect of SDS at 5 mg/mL and of caprate administered at different luminal concentrations (5, 10, and 20 mg/mL) and pH (6.5 and 7.4). The small intestinal permeability of enalaprilat increased by 8- and 9-fold with SDS at 5 mg/mL and with caprate at 10 and 20 mg/mL but only at pH 7.4, where the free dissolved caprate concentration is higher than at pH 6.5 (5 vs. 2 mg/mL). Neither SDS nor caprate at any of the investigated luminal concentrations enhanced absorption of the larger peptide hexarelin. These results show that caprate requires doses above its saturation concentration (a reservoir suspension) to enhance absorption, most likely because dissolved caprate itself is rapidly absorbed. The absent effect on hexarelin may partly explain why the use of permeation enhancers for enabling oral peptide delivery has largely failed to evolve from in vitro evaluations into approved oral products. It is obvious that more innovative and effective drug delivery strategies are needed for this class of drugs.

CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study1

No result from this study comes from a test of the peptide.

Studies that did not test the peptide alone1

In this study, Hexarelin was a lab tool or a carrier, part of a mix, or the subject of a lab method. These results are not evidence about taking Hexarelin.

01AnimalNot a test of Hexarelin aloneAnimal study (in vivo)Pharmacokinetics
In rat intestinal perfusion, neither SDS nor caprate at any tested concentration enhanced absorption of hexarelin.
In plain wordsIn rats, the gut absorption enhancers SDS and caprate did not increase absorption of hexarelin.
Peptide
Hexarelin
Outcome
No significant changeIntestinal absorption of hexarelin with SDS or caprate
Study
ratn: not reported in source
Rat single-pass intestinal perfusion
Outcome group
Pharmacokinetics · Pharmacology
Source sentences
Summary
Neither SDS nor caprate at any of the investigated luminal concentrations enhanced absorption of the larger peptide hexarelin.
1 context sentence(design, population, supporting numbers)
Summary · context
The objective of this single-pass perfusion study in rat was to investigate the effect of SDS at 5 mg/mL and of caprate administered at different luminal concentrations (5, 10, and 20 mg/mL) and pH (6.5 and 7.4).
In this study, Hexarelin was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Hexarelin.
Show in the study text Report a problemFND-3199192401

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Version history

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Version 2Current
13 Oct 2026, 21:44 UTC
Study results updated
Version 1
13 Oct 2026, 16:31 UTC
First added · source update from Europe PMC

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