Bioequivalence of drugs in the skin

In an FDA (Food and Drug Administration) co-funded project we have developed a methodology to determine bioequivalence of topical drugs






Generic drugs are an attractive alternative to reference listed drugs because they have the same treatment effect at considerably lower costs. For FDA approval, a generic drug demonstrate bioequivalence by showing the same pharmacokinetic behavior as the reference listed drug. For most drugs a simple pharmacokinetic measurement in the blood is sufficient but for topical dermal drugs adequate measurements in the skin have not been available. dOFM now offers a new solution to measure these drugs directly in the skin.

OFM Reference Project - FDA Bioequivalence of drugs in the skin


Different acyclovir formulations were applied to the skin of healthy volunteers. ISF samples were obtained by using dOFM and acyclovir concentrations in these ISF samples were used to compare the effectiveness of the tested formulations.


The successful application of OFM to determine bioequivalence and non-bioequivalence of hydrophilic, topically applied creams was demonstrated in this project for the first time.

In a subsequent project with the U.S. FDA we are currently developing a standardized setup to reduce data variability in clinical trials dealing with topical dermal drugs.

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