A Bio-Adhesive Formulation for the Delivery of Anti-Fungal Agents to the Oesophagus

Abstract

Oesophageal candidiasis is an increasing clinical condition associated mainly with immunocompromised patients; effective topical therapy minimises the amount of drug used and reduces the many unwanted side effects associated with systemic therapy. This study will investigate the in vitro potential of a drug delivery device designed to target the oesophagus for the delivery of antifungal agents in the treatment of oesophageal candidiasis. Xanthan gum and chitosan were selected respectively as a bio adhesive hydrogels that can coat the infected area and to deliver locally acting drugs. Metronidazole and miconazole nitrate were used as model drugs incorporated into the bio adhesive system to examine the factors that control the extent and duration of adhesion of formulation as well as the controlled release of drug from such systems. PEG and glycerol were used as excipient said to the solubility of the model drugs. The diffusion of the model drug from the formulation to the site of action was assessed using Franz cell apparatus. The retention of the formulation on the biological substrate was evaluated using an in vitro model (Batchelor et al., 2002). The efficacy of the model drug was measured according to a microdilution method with the minimal inhibitory concentration (MIC) values (National Committee for Clinical Laboratory Standards,1997). The hydrogels containing anti-fungal agents showed good release ability over 30 minutes and were retained on the oesophageal mucosa up to 30 minutes after washing.