Selection of topically applied non-steroidal anti-inflammatory drugs for oral cancer chemoprevention

Topical delivery of non-steroidal anti-inflammatory drugs through the oral mucosa has been used for oral cancer chemoprevention. Local permeation of these agents has been one of the major concerns. Here we propose an approach to predict the permeability of topically applied agents for oral cancer chemoprevention. In theory, the total flux through the oral mucosa (J(max)) can be estimated by adding the transcellutar flux (J(TC)) and the paracettutar flux (J(PC)). To target the Cox-2 enzyme in oral epithelial cells, it is desirable to maximize the theoretical activity index, the ratio of J(TC) and IC50 of a Cox-2 inhibitor (J(TC)/IC50-Cox-2). Among the 12 commonly used NSAIDs, cetecoxib, nimesulide and ibuprofen had the highest values and may be the agents of choice to target Cox-2 in oral epithelial cells through topical application. Based on these calculations, a tong-term chemopreventive experiment using celecoxib (3% or 6%) through topical application was performed in a DMBA induced hamster oral cancer model. Both 3% and 6% reduced the incidence of squamous cell carcinoma at the post-initiation stage. (c) 2005 Elsevier Ltd. All rights reserved.