The Interplay Between Liver First-Pass Effect and Lymphatic Absorption of Cannabidiol and Its Implications for Cannabidiol Oral Formulations

Clin Pharmacokinet. 2020 Dec;59(12):1493-1500. doi: 10.1007/s40262-020-00931-w.

Abstract

For highly lipophilic drugs, passage into the intestinal lymphatic system rather than the portal vein following oral administration may represent a major alternative route of delivery into the general circulation. Increasing intestinal lymphatic transport provides an effective strategy to improve oral bioavailability when hepatic first-pass metabolism is a major rate-limiting step hampering access to the systemic circulation after oral dosing. The transfer of orally administered, highly lipid-soluble drugs to the lymphatic system is mediated by their association with chylomicrons, large intestinal lipoproteins that are assembled in the enterocytes in the presence of long-chain triglycerides or long-chain fatty acids. Due to its very high lipophilicity, cannabidiol (CBD) has physicochemical features (e.g. logP = 6.3) consistent with an oral absorption mediated at least in part by transport via the intestinal lymphatic system. CBD also undergoes extensive first-pass hepatic metabolism. Formulation changes favoring diversion of orally absorbed CBD from the portal to the lymphatic circulation pathway can result in reduced first-pass liver metabolism, enhanced oral bioavailability, and reduced intra- and intersubject variability in systemic exposure. In this manuscript, we discuss (1) evidence for CBD undergoing hepatic first-pass liver metabolism and lymphatic absorption to a clinically important extent; (2) the potential interplay between improved oral absorption, diversion of orally absorbed drug to the lymphatic system, and magnitude of presystemic elimination in the liver; and (3) strategies by which innovative chemical and/or pharmaceutical delivery systems of CBD with improved bioavailability could be developed.

MeSH terms

  • Administration, Oral
  • Biological Availability
  • Cannabidiol* / pharmacokinetics
  • Humans
  • Intestinal Absorption
  • Liver / metabolism*
  • Lymphatic System*
  • Pharmaceutical Preparations*

Substances

  • Pharmaceutical Preparations
  • Cannabidiol