H-AN-006 In Vitro Permeation of Acyclovir Cream Using Phoenix DB-6 Request

Summary
The US FDA recommends full media replacement at each sampling interval when performing IVPT studies of Acyclovir cream due to “apparent negative flux”. Full replacement requires extensive analysist intervention or complicated automation and often the use of LC-MS to detect such low concentrations, all of which can be costly and complicated. Choosing to use an aliquot sampling method for IVPT can be simpler and allow for the use of less-expensive LC equipment, as the concentration of analyte remains high enough during the study to allow accurate quantitation using HPLC UV detection, while maintaining solubility sink conditions throughout the extended run. This research study demonstrates that aliquot sampling is suitable for IVPT studies of Acyclovir cream when using modern diffusion apparatus, likely due to diffusion cell design innovations which ensure receptor chamber and arm stem homogeneity, eliminating “apparent negative flux”, a phenomenon that industry hasn’t been able to explain. Although this study used acyclovir as the test ingredient, partial media replacement can be used with other compounds such as steroidal or antifungal compounds.

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