Novel formulations for use in the oral cavity

Abstract

The aim of this thesis was to develop a number of novel products for use in the oral cavity. Periodontitis is a condition characterized by the loss of clinical attachment to the gum, along with resorption of the alveolar bone. This process results in the formation of a periodontal pocket, increased tooth mobility and ultimately tooth loss. The condition develops as a result of a localized bacterial infection of mixed pathogenic microflora, due to the accumulation of subgingival plaque. A novel drug delivery system was developed, for the localized treatment of periodontitis. The localized treatment of the condition is considered preferable as high local concentrations can be achieved, without concomitant side effects. It used the novel excipient, halloysite, to offer a controlled release of tetracycline base. Halloysite is a microtubular material and it is possible to load drug into the lumen of the microtubules, after which a chitosan coating can be applied, which further retards release from the halloysite. Tetracycline was the antibiotic chosen for the product, as it has been widely shown to be efficacious against periodontal pathogens. A delivery system based on a thermoresponsive polymer, poloxamer 407, was developed, as it offered ease of administration. Both the gelling temperature and the adhesive ability of the polymer system was modified, to produce the most suitable system. The final product was tested in vivo in a dog model, and showed good retention and positive antimicrobial activity, with drug release occurring over a 6- week period.