Drug Diffusion and Nano Excipient Formation Studied by Electrodynamic Methods

• Main Author: Brohede, Ulrika
• Format: Doctoral Thesis
• Language: English
• Published: Uppsala universitet, Institutionen för teknikvetenskaper 2007
• Subjects: Functional materials; drug release; electrodynamic methods; diffusion; Funktionella material
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7818; http://nbn-resolving.de/urn:isbn:978-91-554-6864-4

New smart drugs demand new smart drug delivery systems and also new smart analysis methods for the drug delivery process and material characterization. This thesis contributes to the field by introducing a new electrodynamic approach for studying the drug diffusion proc-esses as well as the formation of a new type of drug delivery systems, the so called mesoporous nano excipients. Drug diffusion processes from different pharmaceutical materials were examined. The transport of charged drug substances was investigated by electrodynamic methods; either as a release process governed by diffusion using the alternating ionic current method or by applying a voltage, sinusoidal or dc, to force the drug ions to move in an electric field. Temperature-dependent drug release from microcrystalline cellulose tablets was examined in order to extract information about the diffu-sion process. Percolation theory was also employed to binary mixtures of an insoluble and electrically insulating matrix material together with a soluble and ionic conducting drug. Further, dielectric spectros-copy was proven to be a powerful method for examining the state of vesicle formation of drug and surfactant molecules in a carbopol gel. Finally, a new potential class of pharmaceutical materials were exam-ined, namely the AMS-n mesoporous materials, showing that the al-ternating ionic current method is powerful both in the study of the synthesis of and in the release process from these.