Ibuprofen-Loaded, Nanocellulose-Based Buccal Films: The Development and Evaluation of Promising Drug Delivery Systems for Special Populations

The objective of this work was to investigate the use of nanocrystalline cellulose (NCC) as a drug-delivery excipient for buccal films. Gel-like dispersions were created by blending either gel or powder NCC (gNCC or pNCC) with natural polymers (alginate, pectin, or chitosan) in water, with glycerol serving as a plasticiser. Ibuprofen (IBU) as an active pharmaceutical ingredient (API) was dissolved in a self-microemulsifying drug delivery system (SMEDDS) to improve its solubility prior to its addition to gel-like dispersions. Dispersions were dried, and resulting films were cut to 3 cm × 1.5 cm size, appropriate for buccal delivery. Rheological measurements revealed that shorter, thinner, and less crystalline nanocellulose fibres are more favourable for stronger gel properties. While overall, weaker gel structure prior to film casting also resulted in shorter disintegration time, this was not the case for NCC-chitosan films; here, the low solubility of chitosan in neutral media proved to be the main obstacle. Nevertheless, the prolonged disintegration of NCC-chitosan films did not impact the dissolution of IBU, as these films exhibited the fastest dissolution rate, followed by NCC-pectin and NCC-alginate. Furthermore, NCC properties significantly influenced the dissolution behaviour of the chitosan formulations, with gNCC favouring faster IBU release due to weaker gel formation prior to film casting.