Validation and testing of a new iontophoretic continuous flow through transport cell

Area of Science:

• Pharmacokinetics and Drug Delivery
• Biophysical Chemistry
• Materials Science in Medicine

Background:

• Accurate measurement of drug transport kinetics is essential for developing effective transdermal delivery systems.
• Existing transport cells can introduce artifacts, complicating the interpretation of experimental data.
• Minimizing cell and protocol contributions to transport kinetics is key for reliable flux determination.

Purpose of the Study:

• To introduce a new continuous flow-through transport cell designed for enhanced accuracy in kinetic measurements.
• To validate the performance of the new transport cell using established methods and model compounds.
• To assess the iontophoretic transport of apomorphine across human stratum corneum using the developed system.

Main Methods:

• Development of a continuous flow-through transport cell with minimized cell conformation and experimental protocol influences.
• Validation using methylene blue and apomorphine washout periods.
• Iontophoretic transport studies of apomorphine across human stratum corneum.
• Calculation of apparent versus intrinsic flux deviations.

Main Results:

• The transport cell demonstrated minimal contribution (< or = 3%) to overall transport rates.
• Sink conditions were reliably achieved at flow rates of 6.5 ml h-1 or higher.
• Steady-state iontophoretic flux of apomorphine was measured at 90 +/- 6 nmol cm-2 h-1.
• The supporting membrane showed no significant impact on transport rates.

Conclusions:

• The new continuous flow transport cell provides a reliable method for measuring intrinsic drug flux.
• Validated experimental conditions ensure that measured apparent flux accurately reflects intrinsic flux.
• This system is suitable for precise evaluation of transdermal drug transport, including iontophoresis.