Passive Diffusion of Transdermal Glucose: Noninvasive Glucose Sensing Using a Fluorescent Glucose Binding Protein.

The motivation for this study was to determine if a statistically significant correlation exists between blood glucose (BG) and transdermal glucose (TG) collected by passive diffusion. A positive outcome will indicate that noninvasive passive TG diffusion is a painless alternative to collecting blood through a break on the skin. Sampling involves placing a small volume of buffer solution on the surface of membrane or skin for 5 minutes.

Transdermal flux predictions for selected selective oestrogen receptor modulators (SERMs): comparison with experimental results.

The aim of this work was to evaluate the feasibility of delivering transdermally a series of highly lipophilic compounds (log P ~4-7), comprising several selective oestrogen receptor modulators and a modified testosterone (danazol). The maximum fluxes of the drugs were predicted theoretically using the modified Potts & Guy algorithm (to determine the permeability coefficient (kp) from water) and the calculated aqueous solubilities. The correction provided by Cleek & Bunge took into account the contribution of the viable epidermal barrier to the skin permeation of highly lipophilic compounds.

Correlation between sweat glucose and blood glucose in subjects with diabetes.

Background: Sweat contains glucose that can accurately reflect blood glucose. However, skin surface glucose can confound these measurements.

Methods: A perfusion method was used to rapidly harvest sweat from forearm sites on human subjects.

Transdermal drug delivery: clinical considerations for the obstetrician-gynecologist.

Introduction: The first transdermal drug delivery system was introduced in the United States over 20 years ago. Created as an alternative route of administration to improve patient compliance as well as to reduce side effects, the transdermal delivery of drugs now represents a $1.5 to $2 billion market and is growing rapidly.

Physiological differences between interstitial glucose and blood glucose measured in human subjects.

Objective: This study investigated whether glucose readings from a sensor sampling in interstitial fluid differ substantially from blood glucose (BG) values measured at the same time.

Research Design And Methods: We have evaluated the relationship between BG and glucose extracted from interstitial fluid using the GlucoWatch (Cygnus, Redwood City, CA) biographer, a device that collects glucose from subcutaneous interstitial space through intact skin by application of a low electric current. We evaluated the relative change in the interstitial glucose (IG) signal (IGS) as measured by the biographer versus BG using a normalized two-point sensitivity index (NSI).

Frequency and thermal effects on the enhancement of transdermal transport by sonophoresis.

The aims of this work were: (i) to examine the role of ultrasound (US) frequency and intensity on the transport of glucose and mannitol across porcine skin in vitro, (ii) to quantify the energy delivered to the skin during application of low-frequency sonophoresis, and (iii) to 'deconvolute' the thermal effect, induced by US application to the skin, to the enhanced permeability of the cutaneous barrier. Low- (20 kHz) and high-frequency (10 MHz) sonophoresis were first compared. Only low frequency US resulted in significantly increased permeation.

Glucose monitoring by reverse iontophoresis.

Glucose can be extracted through intact skin by electro-osmotic flow (a process called 'reverse iontophoresis') upon the application of a low-level electrical current. Recently we have combined iontophoretic extraction with an in situ glucose sensor in a device called the GlucoWatch biographer. Clinical results with this device show close tracking of blood glucose over a range of 2.