Abstract
Cannabidiol (CBD) is a highly lipophilic compound with poor oral bioavailability, mainly attributed to its low aqueous solubility (intrinsic solubility 0.1-0.7 µg/mL, in pure water). This low solubility, combined with extensive first-pass metabolism, results in low oral bioavailability (ca. 6%).. The present study sought to enhance the apparent solubility of CBD through liposomal and self-microemulsifying drug delivery systems (SMEDDS) formulations. Liposomes containing ω-3 fatty acids, along with SMEDDS formulations, were prepared and characterized in terms of hydrodynamic diameter, polydispersity index, and zeta potential. In addition, tablets, which were produced from the lyophilized formulations, were placed into enteric-coated capsules to protect CBD from degradation in the acidic gastric environment, thereby limiting its conversion to undesired metabolites and improving its stability. Both liposomal and SMEDDS systems exhibited markedly enhanced dissolution profiles compared with tablets containing pure CBD. Specifically, dissolution reached 81% for L1, 94% for L2, 69% for S1, and 66% for S2, whereas from the pure CBD tablets, the release reached only 28% after 720 minutes, under simulated intestinal conditions (pH 6.8). The lyophilized formulations were further characterized using scanning electron microscopy (SEM) and powder X-ray diffraction (XRPD), which confirmed that CBD was present in an amorphous or molecularly dispersed state within the systems. Moreover, evaluation using the DPPH assay demonstrated that the antioxidant activity of CBD was preserved following its incorporation into both liposomal and SMEDDS formulations.Overall, the results suggest that liposomal carriers and SMEDDS represent promising oral delivery scaffolds for improving the solubility and dissolution performance of cannabidiol.
Biography
Marilena Vlachou is a Professor at the National and Kapodistrian University of Athens (NKUA), Greece. She obtained her Pharmacy and PhD degree, in Pharmaceutical Technology, from the NKUA. Prior to obtaining her PhD degree she moved to the University of Rhode Island, U.S.A., as a Visiting Research Scientist, to conduct cutting edge research, related to Pharmaceutical Technology techniques. In NKUA, she teaches, both undergraduate and postgraduate courses, related to the fields of Pharmaceutical Technology, Physical Pharmacy and Nanotechnology. She has co-authored the textbook entitled “Pharmaceutical Technology I: Principles of Physical Pharmacy and Nanotechnology”, and many book chapters. She has presented her research work in more than eighty (80) International Scientific Conferences and she has published more than a hundred research articles in peer-reviewed Journals.
