Reverse iontophoresis of lithium: electrode formulation using a thermoreversible polymer

Area of Science:

• Pharmacokinetics and Drug Delivery
• Analytical Chemistry
• Materials Science

Background:

• Reverse iontophoresis is a non-invasive technique for transdermal analyte extraction.
• Traditional methods face challenges in sample handling and recovery.
• Developing improved receptor media is crucial for enhancing analytical accuracy.

Purpose of the Study:

• To evaluate thermoreversible Pluronic F127 gel as a receptor medium for reverse iontophoresis.
• To assess the efficiency of simultaneous lithium and sodium extraction.
• To establish the correlation between extracted analytes and subdermal concentrations.

Main Methods:

• Preparation of a 20% (w/w) aqueous Pluronic F127 gel.
• In vitro iontophoresis experiments using the gelled receptor at the cathodal chamber.
• Quantification of extracted lithium and sodium after cooling the gel to 4°C.
• Analysis of lithium extraction fluxes and lithium-to-sodium ratios.

Main Results:

• Pluronic F127 gel demonstrated suitable consistency and skin contact during iontophoresis.
• Easy recovery of lithium and sodium from the cooled gel was achieved.
• Lithium extraction fluxes and the lithium-to-sodium ratio correlated linearly with subdermal lithium concentrations.

Conclusions:

• Thermoreversible polymer solutions, like Pluronic F127 gel, provide a simple and convenient sample handling method for reverse iontophoresis.
• This approach enhances the practicality of transdermal analyte extraction for monitoring.
• The method shows promise for accurate, non-invasive quantification of analytes like lithium.