Towards a more efficacious treatment for gingivitis: Hydrogel-forming solid oral dosage forms for the localised oral delivery of antimicrobials

Gingivitis belongs to a collection of conditions referred to as periodontal disease and is strongly associated with the unchecked growth of dental plaque. Dental plaque is composed of microbial biofilm which is capable of rapidly spreading over a newly cleaned tooth’s surface. Found in almost all samples of plaque, Streptococcus spp. are particularly problematic due to their ability to colonise the tooth’s pellicle, thus providing multiple adhesion points for other microorganisms. Plaque-induced gingivitis is by far the most common causative factor for gingival disease, and if left untreated will progress to periodontitis and eventually tooth loss. Current approaches to treatment include mechanical debridement (manual and electric tooth brushing, flossing, etc.), antibiotic and/or antimicrobial therapies (including mouthwashes and macrolide antibiotics such as azithromycin) and finally, extraction of affected teeth.

Our previous work has looked at the application of mucoadhesive hydrogels and tablets to deliver common antifungals such as chlorhexidine and certain sugars (which are also antimicrobial). Hydrogels are water-rich, malleable materials that can absorb excess wound fluids while releasing medicinal agents, such as antimicrobials and those that promote wound healing. Hydrogels dressings can be formulated to provide controlled, targeted release of antimicrobial agents which is facilitated by bioadhesive, stimuli (microbial infection)-responsive characteristics. Antimicrobial encapsulation inside hydrogels combines the potential of a controlled release delivery system to achieve effective drug delivery whilst reducing problems related to targeting, biodistribution and bioavailability of agents, especially when administering cytotoxic agents. The combination of responsive, moisture promoting hydrogels with tablet delivery may improve treatment of chronic, persistent gingivitis.

To this end, a systematic pharmaceutical investigation of tablets, hydrogels and hydrogel-forming tablets will be conducted, encompassing (but not limited to) unloaded and loaded hydrogel stability, rheology, encapsulation efficiency, tablet powder flow properties as well as drug release, associated mathematical models and finally antimicrobial studies. The novelty lies in their ability to adhere to the buccal mucosa and increase lubrication in the oral cavity, whilst still delivering a controlled, prolonged dose of drug. We are interested in exploring the novel approach of blending these two delivery systems together into a hydrogel-forming tablet to treat gingivitis infection, as well as the associated sore, inflamed gums and oral discomfort that patient’s experience. There is also the added possibility of including adjuvants into the formulation to improve their antimicrobial activity, such as penetration enhancing essential oils and quorum sensing molecules. In addition to pharmaceutical formulation developments, a range of cell viability and cytotoxicity assays will also be conducted on the hydrogel-forming tablets.

The successful candidate will be trained in a range of advanced techniques used in the preparation of hydrogels and develop skills in microbiology. Laboratory work and characterization will be undertaken within the University of Wolverhampton’s new Science Centre, the Rosalind Franklin building, which houses a broad range of state-of-the-art research facilities suitable for undertaking this multidisciplinary project.