Microwave non-destructive testing technique for characterization of HPMC-PEG 3000 films

Abstract

The capacity of microwave non-destructive testing (NDT) technique to characterize the matrix property of binary�polymeric films�for use as�transdermal�drug delivery system�was investigated.�Hydroxypropylmethylcellulose�(HPMC) and�polyethylene glycol�(PEG) 3000 were the choice of�polymeric matrix�and�plasticizer, respectively with�loratadine�as the model drug. Both blank and drug loaded HPMC-PEG 3000 films were prepared using the solvent-evaporation method. These films were conditioned at the�relative humidity�of 25, 50 and 75% prior to�physicochemical characterization�using the established methods of ultra-violet�spectrophotometry,�differential scanning calorimetry�and�Fourier transform infrared spectroscopy�methods, as well as, novel microwave NDT technique. Blank films exhibited a greater propensity of polymer�polymer interaction at the O�H domain upon storage at a lower level of�relative humidity, whereas drug loaded films exhibited a greater propensity of polymer�polymer, polymer�plasticizer and/or drug�polymer interaction via the O�H, C�H and/or aromatic Cdouble bondC functional groups when they were stored at a lower or moderate level of relative humidity. The absorption and transmission characteristics of both blank and drug loaded films for microwave varied with the state of polymer�polymer, polymer�plasticizer, and/or drug�polymer interaction of the matrix. The measurements of microwave NDT test at 8 and 12�GHz were sensitive to the polar fraction of film involving functional group such as O�H moiety and the less polar environment of matrix consisting of functional groups such as C�H and aromatic Cdouble bondC moieties. The state of interaction between polymer,�plasticizer�and/or drug of a binary polymeric film can be elucidated through its absorption and transmission profiles of microwave.