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Accurate determination of skin flux from flow-through diffusion cell data
1Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City 84112, USA.
Pharmaceutical Research
|December 1, 1995
Summary
Accounting for drug accumulation in the receiver chamber improves the accuracy of intrinsic flux determination. The Japp2 method, which considers accumulation, provides a more accurate measurement of drug diffusion across membranes compared to Japp1.
Area of Science:
- Pharmacokinetics
- Drug Delivery Systems
- Membrane Transport
Background:
- Accurate determination of drug flux across membranes is crucial for understanding drug delivery and efficacy.
- Traditional methods may not fully account for dynamic processes within diffusion cells, potentially leading to inaccurate flux estimations.
Purpose of the Study:
- To evaluate the accuracy and ease of determining intrinsic drug flux by incorporating receiver chamber accumulation.
- To compare two apparent flux calculation methods (Japp1 and Japp2) in transdermal diffusion studies.
Main Methods:
- Mathematical modeling of transdermal diffusion was employed.
- Receiver concentration data were generated for single and bilayer membranes.
- Two flux values, Japp1 (without accumulation) and Japp2 (with accumulation), were calculated and compared.
Main Results:
- Japp1 generally provided inaccurate estimates of intrinsic flux.
- Japp2 values demonstrated significantly higher accuracy, particularly before peak receiver concentrations.
- The accuracy of Japp2 was largely unaffected by receiver volume, flow rate, or donor volume.
Conclusions:
- Japp2 accurately measures intrinsic drug flux across membranes, except at time zero, due to its consideration of solute accumulation.
- For slowly permeating drugs or specific experimental conditions, Japp1 may suffice.
- Early-time data are essential for accurate Japp2 calculations; otherwise, the inverse Laplace method is preferred.