High-Throughput Screening Assay for Testing Transdermal Formulations

DESIGNING A HIGH-THROUGHPUT SCREENING ASSAY FOR TESTING TRANSDERMAL FORMULATIONS 

Franz diffusion cells (FDC) remain the workhorse of all permeation experiments in transdermal studies. FDCs use the permeation of a solute, assessed by high pressure liquid chromatography (HPLC) or radiation, to evaluate the effect of penetration 

Any high-throughput assay used for screening of transdermal formulations should meet the following requirements  

To map a reasonable experimental space of 0(106), formulations would require 0(100) years with FDCs. Increasing the throughput by at least two to three orders of magnitude would result in significant improvement in the effort and time spent in the very first stage of formulation development. 

Use of a surrogate end point that is quick and easy to obtain Permeation experiments using a radiolabeled, fluorescent, HPLC-detectable, or radio immuno assay/enzyme linked immuno sorbent assay-detectable marker necessitate the need of extensive sample handling and sample analysis. This accentuates the cost of sample analysis and overall time spent in characterizing the efficacy of formulations. Furthermore, current state of the art fluidics systems put a fundamental limit on the number of samples handled in a given time. 

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