A new approach to enhance efficiency of transdermal iontophoresis.

by Zhao Li.Thesis (M.Phil.)--Chinese University of Hong Kong, 1996.Includes bibliographical references (leaves 148-158).ACKNOWLEDGMENTS --- p.IABSTRACT --- p.IILIST OF FIGURES --- p.VIIILIST OF TABLES --- p.XLIST OF PHOTOGRAPHS --- p.XILIST OF EQUIPMENTS --- p.XIILIST OF APPENDICES --- p.XIIABBREVIATIONS --- p.XIIIChapter Chapter 1. --- Introduction and Literature Review --- p.1Chapter I. --- Introduction --- p.1Chapter II. --- Literature Review --- p.6Chapter 1.1. --- Foreword --- p.6Chapter 1.2. --- Advantages of iontophoresis --- p.7Chapter 1.3. --- Historical background --- p.7Chapter 1.4. --- Definitions --- p.9Chapter 1.5. --- Principles of ionic transport in an electric field --- p.10Chapter 1.6. --- Theory and mechanism of iontophoretic delivery --- p.12Chapter 1.7. --- Development of iontophoretic devices --- p.13Chapter 1.8. --- Process of transdermal drug delivery --- p.14Chapter 1.9. --- Clinical application of iontophoresis --- p.14Chapter 1.10. --- Present problems of iontophoretic devices --- p.16Chapter 1.11. --- Effects of physiochemical factors on iontophoretic delivery --- p.20Chapter 1.11.1. --- pH --- p.20Chapter 1.11.2. --- Ionic strength --- p.21Chapter 1.11.3. --- Buffer solution --- p.21Chapter 1.11.4. --- Electrode --- p.22Chapter 1.11.5. --- Concentration and temperature --- p.22Chapter 1.11.6. --- Molecular weight --- p.22Chapter 1.11.7. --- Blood supply --- p.23Chapter 1.11.8. --- Pharmaceutical additives --- p.23Chapter 1.11.9. --- Four-electrodes system --- p.24Chapter 1.11.10. --- Skin properties --- p.24Chapter 1.12. --- Future prospect --- p.25Chapter Chanter 2. --- Design of PSPDC iontophoretic deviceChapter 2.1. --- Introduction --- p.29Chapter 2.2. --- Materials and Methods --- p.30Chapter 2.2.1. --- Principle of the new iontophoretic device --- p.30Chapter 2.2.2. --- Mechanism of pulsed short-circuit system --- p.32Chapter 2.2.3. --- Structure of self-made PSPDC device --- p.34Chapter 2.2.4. --- Safety system of the PSPDC device --- p.35Chapter 2.2.5. --- Test of the electrical properties of PSPDC device --- p.36Chapter 2.3. --- Results --- p.41Chapter 2.3.1. --- Efficacy of pulsed short-circuit system --- p.41Chapter 2.3.2. --- "Output characteristics of PDC, DC and PSPDC fields" --- p.42Chapter 2.3.3. --- Impact energy and depolarization action of PDC and PSPDC fields --- p.47Chapter 2.4. --- Discussion and Summary --- p.52Chapter 2.4.1. --- Discussion --- p.52Chapter 2.4.2. --- Summary --- p.53Chapter 2.5. --- Photochrome and Appendix --- p.56Chapter Chapter 3. --- Iontophoretic ExperimentChapter 3.1. --- Introduction --- p.65Chapter 3.2. --- Materials and Methods --- p.67Materials --- p.67Methods --- p.68Chapter 3.2.1. --- Permeation experiments of different electric fields-an in vitro study --- p.69Chapter 3.2.2. --- Comparison of efficiency between DC and PSPDC-excised skin --- p.70Chapter 3.2.3. --- Comparison of permeation efficiency between DC and PSPDC- pedicled skin flap --- p.71Chapter 3.2.4. --- In vivo permeation experiment in the rat --- p.72Chapter 3.2.5. --- In vivo permeation experiment with the radioisotope labelled molecules --- p.73Chapter 3.2.6. --- Clinical observations of PSPDC iontophoresis device --- p.74Chapter 3.2.7. --- Experiments on the alteration and recovery of skin impedance under prolonged iontophoresis --- p.75Chapter 3.2.8. --- Skin damage by iontophoresis --- p.76Chapter 3.3. --- Results: --- p.77Chapter 3.3.1. --- Permeation rates of different electric fields (in vitro: excised rat skin) --- p.77Chapter 3.3.2. --- Comparison between DC and PSPDC-- excised rat skin --- p.78Chapter 3.3.3. --- Comparison between DC and PSPDC-- pedicled skin --- p.79Chapter 3.3.4. --- In vivo permeation experiment in the rat --- p.80Chapter 3.3.5. --- In vivo permeation experiment with radioisotope labelled molecules --- p.81Chapter 3.3.6. --- Alteration and recovers of skin impedance under prolonged iontophoresis --- p.88Chapter 3.3.7. --- Observing skin damage by iontophoresis --- p.89Chapter 3.3.8. --- Clinical observation of PSPDC iontophoresis device --- p.90Chapter 3.4. --- Discussion and summary --- p.91Chapter 3.4.1. --- Discussion --- p.91Chapter 3.4.2. --- Summary --- p.96Chapter 3.5. --- Photochrome and Appendix --- p.97Chapter Chapter 4. --- Electrical properties of scar skin and normal skinChapter 4.1. --- Introduction --- p.104Chapter 4.2. --- Material and method --- p.106Chapter 4.2.1. --- Principle of four point measurement method --- p.106Chapter 4.2.2. --- Measurement of electrical impedance of scar and skin with four point method --- p.107Chapter 4.2.3. --- Principle of three point measurement method --- p.108Chapter 4.2.4. --- Measurement of impedance of scar and skin with three point method --- p.110Chapter 4.2.5. --- Imitation equivalent circuit of normal skin with two point method --- p.111Chapter 4.3. --- Results --- p.113Chapter 4.3.1. --- Impedance of scar tissue and skin tissue with four point method --- p.113Chapter 4.3.2. --- Measurement of impedance of scar tissue and skin with three point method --- p.117Chapter 4.3.3. --- "Relationship of resistance, reactance, impedance and frequency" --- p.123Chapter 4.3.4. --- Imitation equivalence circuit of normal skin with point method --- p.124Chapter 4.4. --- Discussion and Summary --- p.125Chapter 4.4.1. --- Discussion --- p.125Chapter 4.4.2. --- Summary --- p.131Chapter 4.5. --- Photochrome and Appendix --- p.132Chapter Chapter 5. --- General discussion and conclusionChapter 5.1. --- General discussion --- p.137Chapter 5.2. --- Conclusion --- p.143References I --- p.148References II --- p.158LIST OF FIGURESFig. 2. 1. Imitating waveform of 1:1PDC and 12:1 PSPDC fields --- p.32Fig. 2. 2. The circuit of Pulsed short-circuit in PSPDC system --- p.32Fig. 2. 3. Block diagram of PSPDC system --- p.35Fig. 2. 4. Scheme of measuring short-circuit action of PSPDC apparatus --- p.36Fig. 2. 5. Measurement of EP of several electric fields --- p.37Fig. 2. 6. Measurement of impact energy and depolarization action --- p.39Fig. 2. 7. The distribution of permeating current and releasing current --- p.41Fig. 2. 8. Comparing the polarization degree of different electric fields --- p.42Fig. 2. 9. Comparing alternating current component of electric fields --- p.4