Transdermal Diffusion Testing with Strat-M^® Synthetic Skin Membranes using Franz Diffusion Cell Systems

Transdermal Diffusion Testing using a Logan Franz Diffusion Cell System

1. First, turn on the circulating water baths.
2. Filter the receptor solution using a vacuum filtration flask. PBS is typically used. Keep the solution under vacuum while the water baths reach temperature.
3. Turn on stirring for all cells.
4. Place the Strat-M^® membrane shiny-side up between the donor and receiver compartment, and clamp together.
5. Fill the receptor compartment with buffer, overflowing through the side tubes to ensure there are no air bubbles.
6. Attach a syringe filled with receptor buffer to the sampling port. This will prevent air bubbles from forming.
7. Check that the receptor buffer in receptor compartment has reached 37 °C. Ensure that no bubbles were generated during warming.
8. Add formulation to the donor compartment to begin experiments.
9. Prior to collecting each sample, check for air bubbles.
10. At each sampling time point, use an appropriately-sized syringe to collect a sample. On a Logan system, first remove the syringe attached to the chamber and replace it with a sampling syringe.
11. Withdraw a small volume of sample from the receptor chamber and discard. This will flush the line.
12. Withdraw a sample for analysis.
13. Once the sample is withdrawn, the original syringe with receptor buffer is reattached to the port, and receptor solution is added back to receptor chamber, making sure there are no air bubbles.
14.  Repeat the sampling process for all desired time points.
15. Analyze samples.

Transdermal Diffusion Testing using a Hanson Vertical Diffusion Cell System

1. Turn on the circulating water baths.
2. Filter the receptor solution using a vacuum filtration flask.
3. Ensure that stirring is on for all cells.
4. Place the Strat-M^® membrane shiny-side down on the dosage wafer, flip the dosage wafer, and add formulation.
5. Use a spatula to ensure formulation is uniformly spread.
6. Place the glass top and metal cover on the wafer.
7. The entire assembly is then slowly placed on the receptor chamber (which is filled with receptor fluid) and clamped.
8. To collect samples on a Hanson Vertical Diffusion Cell system, stop stirring.
9. Fill a syringe with a fixed volume of receptor fluid and attach to the receptor port.
10. Hold an HPLC vial near the sampling port. Slowly push the fixed volume of receptor fluid into the receptor chamber while collecting a sample in the HPLC vial.
11. Remove the syringe and re-start stirring. Repeat for all time points.
12. Analyze samples.