Physical-mechanical, moisture absorption and bioadhesive properties of hydroxypropylcellulose hot-melt extruded films

The objective of this study was to investigate the moisture absorption, phy sical-mechanical and bioadhesive properties of hot-melt extruded hydroxypro pylcellulose (HPC) films containing polymer additives. These additives incl uded polyethylene glycol (PEG) 5%, polycarbophil 5%, carbomer 5%, Eudragit E-100 5%, and sodium starch glycolate (SSG) 5%. Relative humidity (RH) and temperature parameters of the films studied included 25 degrees C at 0, 50, 80 and 100% RH, and 40 degrees C at 0 and 100% RH, stored for 2 weeks. Ten sile strength and percent elongation were determined on an Instron accordin g to the ASTM standards. The bioadhesive properties of the HPC/PEG 3350 5% film and the polycarbophil 5% containing films, with and without PEG, were investigated in vivo on the human epidermis. Although all films studied exh ibited an increase in percent water content as the percent RH increased, th e SSG containing film exhibited an almost three-fold increase in percent wa ter content compared to that of the HPC/PEG film. The temperature storage c ondition of 40 degrees C/100 % RH (versus 25 degrees C/100% RH) increased t he percent water content of the SSG containing him. Percent elongation was highest for films containing polycarbophil 5% (without PEG). In addition, t he HPC film containing polycarbophil 5% exhibited a greater force of adhesi on and elongation at adhesive failure in vivo, and a lower modulus of adhes ion when compared to the HPC/PEG film. A novel approach to determine bioadh esion of films to the human epidermis is presented. (C) 2000 Elsevier Scien ce Ltd. All rights reserved.