Polymer Electrolytes For lontophoretic Drug Delivery

Iontophoresis is a process in which the transport of ions of soluble salts across skin is facilitated by an externally applied potential difference. This technique is novel in providing an external stimulus to ionic drugs in their passage across a skin. Hence, a positively charged drug may be delivered across the skin, by placing it under the positive electrode where it is repelled and attracted toward a negative electrode positioned elsewhere on the body. For the successful operation of this process, the drug must be incorporated into a 'patch-like’ delivery system. Polymer electrolytes offer possibilities for such systems. Polymer electrolytes are ionically conducting solid-like materials in which the ions are to coordinated to an immobile polymer solvent. The most widely studied host polymer for use in polymer electrolytes is poly(ethylene oxide), PEO, in which substantial quantities (up to 4 molar) of salt can be dissolved. These ionically conducting polymers have been extensively used in devices such as lithium polymer batteries and sensors. However, their use as potential candidates for iontophoretic drug delivery in mechanically and chemically stable iontophoretic devices for ionic drugs is novel. In this work, various drugs such as lidocaine hydrochloride, ampicillin sodium, thiamine hydrochloride, lithium citrate, chlorpromazine hydrochloride and lithium chloride have been incorporated into PEO using both water and an acetonitrile/ethanol mixture as casting solvents to form films. The thermal, optical and electrical properties of these films using Differential Scanning Calorimetry (DSC), Variable Temperature Polarising Microscopy (VTPM) and ac impedance have been studied and compared with the well characterised PEO-lithium trillate system. Two drugs in particular, lidocaine hydrochloride and lithium chloride, were identified as promising candidates for iontophoresis in these PEO-based systems. AC Impedance experiments show that the conductivity of these two polymer electrolyte systems varied between 10' * ’ and 10’3 S cm’. at physiological temperature when cast from water.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

De Montfort University

Year dc:date.issued

1999

Author dc:creator

• Sahota, Tarsem Singh

Licence

• https://dora.dmu.ac.uk/bitstreams/87d50f0b-ab29-48d2-84d6-d804319253ee/download