THE USE OF LOW-FREQUENCY DIELECTRIC-SPECTROSCOPY AS A NOVEL MEANS OF INVESTIGATING THE STRUCTURE OF PHARMACEUTICAL GLYCERIDE BASES

The dielectric responses of five glyceride bases have been assessed using low frequency dielectric spectroscopy. It was observed that each base showed different electrical behaviour. In addition, samples were either slow or fast cooled from the melt in order to change the physical structure of each material; in all cases where differences were observed, the slow cooled samples showed a greater response than fast cooled materials. The results are discussed in terms of both the movement of charges within the system and the relationship between these charge movements and the physical structure of the material. It is proposed that the differences in dielectric response between the various samples may be influenced by a number of factors, particularly chemical composition, while the differences between the responses of fast and slow cooled materials may be a reflection of segregation of the components of the bases into distinct regions. These studies indicate that dielectric analysis may be used as a novel means of characterising solid materials of pharmaceutical interest.