AN INVESTIGATION OF BIOADHESION FOR PERIODONTAL AND ORAL MUCOSAL DRUG-DELIVERY

Gel delivery vehicles have ideal placement characteristics for periodo ntal and oral mucosal drug delivery, However, the retention of the veh icle at the site may be of short duration thereby limiting its therape utic effect. Bioadhesion has received little attention as a means of e nhancing vehicle retention in the periodontal pocket and this study ai med to investigate the possible role of this phenomenon to aid oral dr ug delivery. Chitosan, xanthan gum and poly (ethylene oxide) were sele cted as potential vehicles from previous in vitro studies, since all 3 had shown good bioadhesive properties. Retention in the periodontal p ocket was assessed by means of an insoluble fluorescein marker in 8 pa tients, and to the oral mucosa by the retention of a small plastic fil m in 12 subjects. The results showed that fluorescein release from the periodontal pocket was significantly longer for chitosan than for oth er gels or a water control. In contrast, xanthan gum gave the mast pro longed adhesion time on the oral mucosa (153.5 min) followed by poly ( ethylene oxide) (89.3 min) and chitosan (42.6 min), and these times we re all significantly different from each other (p<0.05), The results f rom this study would tend to suggest that the bioadhesive properties o f an aqueous gel map be directly related to its retention both in the periodontal pocket and on the oral mucosa, However, other important fa ctors for mucosal adhesion include the patient acceptability of the fo rmulation and the choice of application site.