Characterization of cellulosic hot-melt extruded films containing lidocaine.

Hot-melt extrusion technology was used to produce thin films containing a model drug, lidocaine, and the cellulosic polymers hydroxypropyl cellulose (HPC) and hydroxypropyl methyl cellulose (HPMC). Two film formulations were extruded and compared, one containing only HPC and the other containing HPC:HPMC (80:20). Thermal analysis of the films using differential scanning calorimetry (DSC) suggested that the drug existed in the amorphous condition, which was confirmed by wide angle X-ray diffractometry. Sustained release of the drug was observed from both of the polymer matrices. Dissolution profiles suggested that HPMC retarded the drug release from HPC:HPMC (80:20) films. However, the mechanism of drug release from both of the films was predominantly diffusion of the drug through the polymer matrices. Incorporation of HPMC also increased both adhesive strength and work of adhesion as compared to the HPC-only films.

Nail morphology studies as assessments for onychomycosis treatment modalities.

The purpose of this investigation was to study the morphology of the human nail treated with chemical penetration enhancers (CPE), bioadhesives and surface modifiers for assessment of topical treatment modalities for onychomycosis. CPEs, including dimethyl sulfoxide (DMSO) and urea were applied to human nail samples. Additional samples were treated with surface modifiers, tartaric acid (TTA) and phosphoric acid gel (PA). Other nail specimens were subjected to the bioadhesive polymers Carbopol 971P and Klucel MF. Atomic force microscopy (AFM), scanning electron microscopy (SEM) and polarized light microscopy (PLM) were utilized to visualize nail morphology and topographical changes of the human nail samples subjected to the various chemical agents. AFM, SEM and PLM micrographs revealed changes in topography to the dorsal layer when CPEs and surface modifiers were applied. Roughness scores as determined by NANOSCOPE IIIA software indicated a 2-fold increase when the dorsal nail layer was subjected to PA versus the control (147.8 vs. 85.0 nm, respectively). In contrast, when carbomer 971P was applied to the dorsal surface, roughness scores decreased significantly (44.6 vs. 85.0 nm, respectively). AFM, SEM and PLM studies of the human nail subjected to various chemical agents may be useful in the design and formulation of novel drug delivery systems for the topical treatment of onychomycosis. The AFM studies offer both a qualitative and quantitative assessment for nail treatment opportunities.