Bioadhesive properties of hydroxypropylcellulose topical films produced byhot-melt extrusion

The objective of this study was to investigate the in vivo bioadhesive prop erties of hydroxypropylcellulose (HPC) films containing seven polymer addit ives on the epidermis of 12 human subjects, including two ethnic sub-groups . HPC films containing polyethylene glycol (PEG 3350) alone, Vitamin E TPGS (TPGS) 5%, sodium starch glycolate 5%, Eudragit E-100 5%, carbomer 974P an d 971P 5%, and polycarbophil 5%, all with and without plasticizer, were pre pared by hot-melt extrusion utilizing a Randcastle Microtruder(R) (Model #R CP-0750). Bioadhesion testing was performed using a Chatillon digital forte gauge DFGS50 attached to a Chatillon TCD-200 motorized test stand to deter mine force of adhesion (FA), elongation at adhesive failure (EAF), and modu lus of adhesion (MA) for the 12 films tested. In vivo, the TPGS-incorporate d film exhibited a two-fold increase in FA when compared to the control fil m containing the PEG 3350 5%. The carbomer 971P and polycarbophil containin g films were determined to have the highest FA and EAF, and the lowest MA o f all films tested. The film containing carbomer 971P had a higher FA than the film containing 974P. In addition, films in one ethnic sub-group exhibi ted higher FA and EAF than the other. Force-deflection profiles obtained fr om these experiments indicate that the force of adhesion, elongation at adh esive failure and modulus of adhesion are a function of the polymer additiv e in the HPC extruded films. The incorporation of carbomer 971P and a polyc arbophil into HPC films increased bioadhesion significantly when compared t o the film containing HPC and PEG 3350. Differences in FA and EAF were disc overed between two ethnic sub-groups tested. (C) 2001 Elsevier Science B.V. All rights reserved.