dissolution medium for transdermal patch

[henderson2000]

i want to determine the drug releasing of a transdermal patch, what kind of dissolution medium can i choose?

[biomartin]

Try isotonic saline solution for patches. This most closely mimics the condition of the skin surface. USP has a "recipe" in the Test Solutions portion. It is approximately 9% weight to volume.

[henderson2000]

Try isotonic saline solution for patches. This most closely mimics the condition of the skin surface. USP has a "recipe" in the Test Solutions portion. It is approximately 9% weight to volume.
Thank you for your input. Someone use 30% methanol or 20% alcohol as medium. They are very different from what you suggest. what do you think of it? and how about the effect of the pH and surfactant? Thank you for your help.

[biomartin]

Unfortuntely, it is impossible to generalize the media that you should use for each specific type of dosage form. I try to stay away from alcohols as much as possible since they generally decrease the discriminatory ability of the method. But, that does not mean you can't use them. The FDA will definitely like to see you try aqueous media first. The USP mimics that request as well. Much of your decision will be based on the solubility of the active ingredient. But, my first instinct is to think that solubility is not too much of a problem in aqueous media for API in a transdermal patch.
The use of isotonic saline is the most biorelavant for these types of systems and is generally the best place to start. I'm working on finding a reference for this topic and will get back to you as soon as I find one mentioning saline media.

Meanwhile, take a look at the USP for nicotine patches. That uses a phosphate solution for the media.