Polymeric films as vehicle for buccal delivery: Swelling, mechanical, and bioadhesive properties.

Purpose. To investigate the suitability of an SCMC (sodium carboxymethyl ce llulose/polyethylene glycol 400/carbopol 934P) and an HPMC (hydroxypropylme thyl cellulose/polyethylene glycol 400/carbopol 934P) films as drug vehicle for buccal delivery. Methods. The mechanical and in vitro bioadhesive stre ngth properties of the films were investigated using texture analyzer equip ment, while swelling behavior was studied in different media, namely, disti lled water and simulated saliva solution. In addition, the in vivo bioadhes ion of the film was studied by estimating the film residence time on buccal mucosa of human volunteers. Results. Increase in carbopol 934P content was found to elevate the elasticity, softness and bioadhesive strength but dec rease the strength and degree of swelling of both SCMC and HPMC films. SCMC films swelled more extensively in distilled water while HPMC films in simu lated saliva solution. HPMC films exhibited greater in vivo bioadhesion alt hough the in vitro bioadhesive strength was lower than SCMC films. Correlat ion existed between the in vivo and in vitro bioadhesion data within the po lymer, but no rank correlation was observed between the two polymers. Concl usion. HPMC films may be preferred over SCMC films as drug vehicle for bucc al delivery as the former was tougher, more elastic, more bioadhesive in vi vo and swelled in a more tolerable manner in the oral cavity than the latte r.