A new in vitro lipid digestion – in vivo absorption model to evaluate the mechanisms of drug absorption from lipid-based formulations

• Published in: Pharmaceutical research Vol. 33; no. 4; pp. 970 - 982
• Main Authors: Crum, Matthew F., Trevaskis, Natalie L., Williams, Hywel D., Pouton, Colin W., Porter, Christopher J. H.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.04.2016; Springer; Springer Nature B.V
• Subjects: Analysis; Animal experimentation; Animals; Biochemistry; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedicine; Digestion; Drug Carriers - chemistry; Drug Carriers - metabolism; Drug delivery systems; Fenofibrate; Fenofibrate - administration & dosage; Fenofibrate - blood; Fenofibrate - chemistry; Fenofibrate - pharmacokinetics; Hypolipidemic Agents - administration & dosage; Hypolipidemic Agents - blood; Hypolipidemic Agents - chemistry; Hypolipidemic Agents - pharmacokinetics; Lipid Metabolism; Lipids; Lipids - chemistry; Male; Medical Law; Pharmacology; Pharmacology/Toxicology; Pharmacy; Rats, Sprague-Dawley; Research Paper; Solubility; Sorption; lipid-based drug delivery systems; intestinal perfusion; supersaturation; absorption; drug solubilisation; in situ intestinal perfusion
• ISSN: 0724-8741; 1573-904X
• DOI: 10.1007/s11095-015-1843-7

Purpose In vitro lipid digestion models are commonly used to screen lipid-based formulations (LBF), but in vitro-in vivo correlations are in some cases unsuccessful. Here we enhance the scope of the lipid digestion test by incorporating an absorption ‘sink’ into the experimental model. Methods An in vitro model of lipid digestion was coupled directly to a single pass in situ intestinal perfusion experiment in an anaesthetised rat. The model allowed simultaneous real-time analysis of the digestion and absorption of LBFs of fenofibrate and was employed to evaluate the influence of formulation digestion, supersaturation and precipitation on drug absorption. Results Formulations containing higher quantities of co-solvent and surfactant resulted in higher supersaturation and more rapid drug precipitation in vitro when compared to those containing higher quantities of lipid. In contrast, when the same formulations were examined using the coupled in vitro lipid digestion – in vivo absorption model, drug flux into the mesenteric vein was similar regardless of in vitro formulation performance. Conclusion For some drugs, simple in vitro lipid digestion models may underestimate the potential for absorption from LBFs. Consistent with recent in vivo studies, drug absorption for rapidly absorbed drugs such as fenofibrate may occur even when drug precipitation is apparent during in vitro digestion.