Evaluation and characterization of hydroxypropyl cellulose and poly(ethylene oxide) hot-melt extruded films for oral mucosal drug delivery

Hydroxypropyl cellulose (HPC) and/or poly(ethylene oxide) (PEO) were used to prepare thin polymeric films containing clotrimazole (CT) or nystatin utilizing hot-melt extrusion (HME) technology. Films containing different molecular weights of HPC and/or PEO and the drug were extruded and investigated for solid-state characteristics (DSC and XRD), moisture-sorption, bioadhesivity, mechanical properties, release characteristics, and physical and chemical stability of the drug within the HME films.; HPC films exhibited brittle fracture with a high elastic modulus and low percent elongation (<5%). In contrast, PEO films were flexible with a low elastic modulus and exceptionally high percent elongation (up to 800%). The release of the drug from both of the films (HPC and PEO) followed zero-order profile (erosion), irrespective of the molecular weight. PEO films exhibited higher bioadhesivity than HPC films.; CT incorporated in both of the polymeric films was found to be in solid solution as indicated by DSC and XRD. However, stability studies indicated that CT incorporated in HPC films was more stable (no recrystallisation observed for 6 months in films stored at 25/60% RH as indicated by DSC and XRD profiles) than CT incorporated in PEO films (CT recrystallisation occurred after storage for 3 months at 25/60% RH). Based on the DSC studies, it has been proposed that the recrystallisation of the drug may be due to the folding (due to HME) and unfolding (upon storage) of the linear PEO chains.; Evaluation of HPC and PEO films containing clotrimazole indicated that HPC films exhibited better stability and sustained release properties than PEO films. However, the PEO films demonstrated more desirable mechanical and bioadhesive properties than the HPC drug-incorporated films. Hence, polymer blends containing HPC and PEO were used successfully to optimize the physico-chemical and mechanical properties and stability of the HME films.