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Labrasol® is an efficacious intestinal permeation enhancer across rat intestine: Ex vivo and in vivo rat studies
- McCartney, Fiona, Jannin, Vincent, Chevrier, Stéphanie, Boulghobra, Hakime, Hristov, Delyan R., Ritter, Nicolas, Miolane, Cédric, Chavant, Yann, Demarne, Frédéric, Brayden, David J.
- Journal of controlled release 2019 v.310 pp. 115-126
- bioavailability, carbon, carboxylic ester hydrolases, colon, decanoic acid, enzyme inhibition, insulin, jejunum, mannitol, mucosa, nonionic surfactants, permeability, polyethylene glycol, rats, solubilization, triacylglycerols
- Labrasol® ALF (Labrasol®), is a non-ionic surfactant excipient primarily used as a solubilising agent. It was investigated here as an intestinal permeation enhancer in isolated rat colonic mucosae in Ussing chamber and in rat in situ intestinal instillations. Labrasol® comprises mono-, di- and triglycerides and mono- and di- fatty acid esters of polyethylene glycol (PEG)-8 and free PEG-8, with caprylic (C8)- and capric acid (C10) as the main fatty acids. Source components of Labrasol® as well as Labrasol® modified with either C8 or C10 as the sole fatty acid components were also tested to determine which element of Labrasol® was responsible for its permeability-enhancing properties. Labrasol® (4, 8 mg/mL) enhanced the transport of the paracellular markers, [14C] mannitol, FITC-dextran 4000, and FITC-insulin across colonic mucosae. The enhancement was non-damaging, transient, and molecular weight-dependent. The PEG ester fraction of Labrasol® also had enhancing properties. When insulin was administered with Labrasol® in instillations, it had a relative bioavailability of 7% in jejunum and 12% in colon. C8– and C10 versions of Labrasol® and the PEG ester fraction also induced similar bioavailability values in jejunal instillations: 6, 5 and 7% respectively. Inhibition of lipases in instillations did not reduce the efficacy of Labrasol®, suggesting that its mechanism as a PE is not simply due to liberated medium chain fatty acids. Labrasol® acts as an efficacious intestinal permeation enhancer and has potential for use in oral formulations of macromolecules and BCS Class III molecules.