Development of Freeze-Dried Hyaluronic Acid Sheets for Healing Oral Mucositis: Influence of Hyaluronic Acid Molecular Weight and Nicotinamide Mononucleotide Loading on Healing Efficacy

Oral mucositis frequently develops during radiotherapy or chemotherapy for head and neck cancer and is characterized by severe pain and impaired eating and speech. It was previously demonstrated that freeze-dried hyaluronic acid (HA) sheets effectively promote the healing of oral mucosal ulcers. This study aimed to optimize the HA sheet formulation by evaluating the effects of HA molecular weight and nicotinamide mononucleotide (NMN) loading on therapeutic efficacy. HA sheets were prepared using HA with four different molecular weights (50, 350, 800, and 2000 kDa), and their therapeutic effects were evaluated in an animal oral ulcer model using 6-week-old male Syrian hamsters. Among the formulations tested, the 800 kDa HA sheet exhibited the greatest healing efficacy, and it showed an excellent balance between buccal retention and the sustained release of NMN for the treatment of oral mucositis. In vitro cytotoxicity assays confirmed that HA, with or without NMN, was non-toxic and suitable for local applications. These findings indicate that HA sheets, particularly those composed of 800 kDa HA, may represent a promising and biocompatible mucoadhesive material for the delivery of NMN and the local treatment of oral mucositis associated with head and neck cancer.