Oral diseases constitute a diverse group of conditions that are responsible for much human suffering. In addition to diseases of the hard tissues of the oral cavity (e.g. dental caries), there are many different pathological conditions affecting the oral mucosa and periodontal tissues. This group includes the commonly found conditions such as gingivitis, periodontal disease, aphthous ulceration and Herpes simplex lesions, as well as the oral manifestations of the less common vesicular-bullous conditions such as bullous pemphigoid, pemphigus, erythema multiforme and lichen planus, as well as many other inflammatory conditions of autoimmune origin.
In some circumstances, localized lesions of the oral (and other) mucosal tissues may be treated by systemic treatment regimes. However, in many cases, systemic management may either be ineffective or be accompanied by unacceptable adverse effects.
While methods of local treatment of mucosal lesions do exist, many of these methods are not particularly effective. For example, medicaments given as lozenges may be partly absorbed into the systemic circulation by way of the mucosal blood vessels, while not achieving a sufficiently high concentration at the lesion site. Other medicaments, such as those intended for relief of painful ulcerative lesions are sometimes administered in the form of ointments, lotions or pastes. These are often difficult to apply, as they do not adhere to the normally moist mucosal surface, which therefore needs to be dried before using these preparations in order to achieve greater adhesion. In addition, pastes and ointments suffer from the disadvantage that they are often difficult to apply to a small, localized area, there being a tendency to spread to adjacent healthy tissue. This problem, combined with rapid dissolution of the thin layer of cream or ointment results in a rapid loss of the desired therapeutically effective concentration at the lesion site. Finally, with most preparations for topical use on mucosal membranes, it may be impossible to maintain sustained delivery to the lesion either because of rapid dissolution of the preparation (e.g. with lozenges, pastilles etc.) or because of systemic absorption, as mentioned hereinabove.
With many oral soft-tissue conditions, regardless of whether these are due to mechanical, thermal or chemical trauma, localized infection, or autoimmune disorders, rapid, initial, relief may be obtained by physically covering the lesions.
Several solid mucoadhesive formulations, and specifically tablets, for use on the skin and/or mucosal tissues have been described in the literature. However, the production of these tablets generally meets with a difficulty associated with the poor flow properties of the mixture containing the sticky components.
It is a purpose of the present invention to provide a solid composition comprising a therapeutic herbal composition for adhesive application to the oral mucosa.
It is another object of the invention to provide a solid composition that overcomes the problems associated with the large-scale industrial production of adhesive mixtures having poor flowability characteristics, without diminishing from the adhesiveness of the composition.
It is a further purpose of the invention to provide such solid composition that overcomes the problems and disadvantages of prior art solid compositions.
Further objects and advantages of the present invention will become apparent as the description proceeds.