Waiting Tai1, Lyndsey Leigh Anderson2, Jonathan Carl Arnold2, Hak-Kim Chan1 & Philip Chi Lip Kwok1
1Advanced Drug Delivery Group, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, NSW 2006, Australia
2Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, NSW 2050, Australia
Summary
Inhalation is a promising administration method for cannabidiol (CBD) due to its higher bioavailability than that from oral delivery. The low solubility of CBD poses a delivery challenge. In this study, spray freeze dried CBD powders with enhanced solubility were produced with dipalmitoylphosphatidylcholine and a hydrophilic bulking agent (mannitol or trehalose dihydrate), referred to as Formulation M and Formulation T, respectively. Formulation M was crystalline, while Formulation T was amorphous. Both showed higher CBD solubility than raw CBD, with Formulation T having the highest value (raw CBD vs Formulation M vs Formulation T: 3.8 µg/mL vs 11.17 µg/mL vs 16.30 µg/mL). The mass median aerodynamic diameter of Formulation T was smaller than that of Formulation M (4.47 µm vs 5.56 µm), as reflected in its higher fine particle fraction < 5 µm (42.7% vs 33.6%). Formulation T may thus be further tested in vivo and adapted to deliver other cannabinoids by inhalation.
Key Message
Both the spray freeze-dried cannabidiol dry powders with mannitol (crystalline) and with trehalose dihydrate (amorphous) were dispersible and with enhanced cannabidiol solubility.