Diagnostic and therapeutic applications of iontophoresis.

Owing to the excellent barrier properties of the stratum corneum, transdermal delivery remains a challenge for a high number of molecules. Iontophoresis is a noninvasive technique which uses a low current to administer polar and charged species through the skin, thereby enlarging the range of drug candidates for transdermal administration. Unlike other techniques of transdermal delivery enhancement, iontophoresis acts on the molecule itself allowing a better control of the dose applied.

Extraction of amino acids by reverse iontophoresis in vivo.

Reverse iontophoresis across the skin is a potentially useful alternative for non-invasive clinical and therapeutic drug monitoring. In this work, the reverse iontophoretic extraction of 17 amino acids was studied in vivo in healthy volunteers. Charged amino acids were primarily extracted towards the electrode of opposite polarity, while zwitterionic species were extracted, more or less equally, to both anode and cathode, suggesting that the net charge on the skin, under the conditions of the experiment, was close to zero.

Extraction of amino acids by reverse iontophoresis: simulation of therapeutic monitoring in vitro.

Reverse iontophoresis across the skin has been investigated as alternative, non-invasive method for clinical and therapeutic drug monitoring. This research investigated the reverse iontophoretic extraction of 19 amino acids present at clinically relevant levels in the subdermal compartment of an in vitro diffusion cell. Over a simulated, systemic concentration range of 0-500 microM, the extraction of amino acids was linear.

Reverse iontophoresis of L-lactate: in vitro and in vivo studies.

This work investigates the reverse iontophoretic extraction of lactate, a widely used marker of tissue distress in critically ill patients and of sports performance. In vitro experiments were performed to establish the relationship between subdermal lactate levels and lactate iontophoretic extraction fluxes. Subsequently, the iontophoretic extraction of lactate was performed in vivo in healthy volunteers.

Noninvasive and minimally invasive methods for transdermal glucose monitoring.

Noninvasive and minimally invasive techniques for monitoring glucose via the skin are reviewed. These approaches rely either on the interaction of electromagnetic radiation with the tissue or on the extraction of fluid across the barrier. The structure and physiology of the skin make the technical realization of transdermal glucose monitoring a difficult challenge.

Simultaneous extraction of urea and glucose by reverse iontophoresis in vivo.

Purpose: Reverse iontophoresis extracts glucose across the skin in the GlucoWatch Biographer, a device to monitor glycemia in diabetes. However, the device must first be calibrated with an invasive "fingerstick" and this has been perceived as a disadvantage. Here, urea, a neutral "internal standard" is extracted simultaneously in an attempt to render the technique completely non-invasive.

Electroosmosis in transdermal iontophoresis: implications for noninvasive and calibration-free glucose monitoring.

Reverse iontophoresis uses a small low electric current to noninvasively extract blood analytes, e.g., glucose, across the skin.

Noninvasive glucose monitoring by reverse iontophoresis in vivo: application of the internal standard concept.

Background: The GlucoWatch Biographer uses reverse iontophoresis to extract glucose across the skin to monitor glycemia in diabetes. The invasive daily calibration with a conventional "fingerstick" has been perceived as a disadvantage. We used an "internal standard" to render the approach completely noninvasive.

Reverse iontophoresis for noninvasive glucose monitoring: the internal standard concept.

Reverse iontophoresis is used by the GlucoWatch Biographer to noninvasively extract glucose across the skin, allowing a diabetic's glycemia to be evaluated every 10 min over several hours. However, before each use, the device must be calibrated with a blood sample assayed in the conventional way. The objective of this study was to identify an approach by which to avoid this invasive step.