Compositions and methods for enhancement of transdermal analyte flux
The present invention relates to compositions for use in analyte monitoring devices. These compositions are useful to increase the flux of analyte across skin, tissue or mucosal surfaces. The compositions include hydrogels and collection reservoir systems comprising ionically conductive materials. The present invention also includes methods of making/manufacturing hydrogels or collection reservoir systems, collection assemblies comprising the hydrogels, electrode assemblies in combination with the hydrogels or collection reservoir systems, and methods of using the same.
1 . A method of determining the concentration of an analyte in a mammalian subject using a monitoring system comprising an iontophoretic sampling device having first and second iontophoretic electrodes, said method comprising:
providing a current to the first and second iontophoretic electrodes of the sampling device in an amount sufficient to effect the extraction of said analyte through the mammalian subject's skin,
i) into a hydrogel composition comprising a) a hydrophilic compound capable of forming a gel in the presence of water, b) an electrolyte, a phosphate buffer present at a concentration of between about 125 mM and about 500 mM, and c) a pH of between about pH 6.5 to about pH 8.5, and
ii) to a catalytic surface of a first sensing electrode, wherein (i) a first surface of said hydrogel is in contact with a tissue surface of the mammalian subject, and (ii) a second surface of said hydrogel is in contact with the first iontophoretic electrode and the first sending electrode;
providing a potential to the first sensing electrode in an amount sufficient to drive electrochemical detection of said analyte or an analyte-related chemical signal;
measuring electrical current generated by the electrochemical detection at the electrode; and
correlating the measured current to a concentration or amount of analyte in the mammalian subject.
2 . The method of claim 1 , wherein the tissue surface is the stratum corneum of skin tissue or a mucosal surface.
3 . The method of claim 1 , wherein the hydrogel comprises glucose oxidase, the analyte is glucose, and the analyte related chemical signal is hydrogen peroxide.
4 . The method of claim 1 , wherein said monitoring system further comprises a second hydrogel composition comprising a) a hydrophilic compound capable of forming a gel in the presence of water, b) an electrolyte, a phosphate buffer present at a concentration of between about 125 mM and about 500 mM, and c) a pH of between about pH 6.5 to about pH 8.5, wherein (i) a first surface of said second hydrogel is in contact with the tissue surface of the mammalian subject, and (ii) a second surface of said second hydrogel is in contact with the second iontophoretic electrode and a second sensing electrode.
5 . The method of claim 1 , wherein said hydrogel composition provides increased transdermal flux relative to extracting the analyte using said iontophoretic sampling device wherein said hydrogel composition instead comprises a hydrophilic compound capable of forming a gel in the presence of water, an electrolyte, a phosphate buffer present at a concentration of equal to or less than 100 mM, and a pH of about pH 7 to about pH 8.
6 . The method of claim 5 , wherein the tissue surface is the stratum corneum of skin tissue or a mucosal surface.