The multilayered structure of Strat-M membrane matches that of human skin.
Correlation between human skin and Strat-M membrane across diffusion rates that vary over four orders of magnitude. Transdermal diffusion testing was performed for several formulation types commonly used for transdermal delivery. Six Franz cells were used for each formulation-three with Strat-M membrane and three with human cadaver skin. The donor chambers were loaded with 500 µL of the formulations. Samples were collected hourly and analyzed with HPLC.
Caffeine solution in propylene glycol shows quantitatively similar increase of diffusion through human skin and Strat-M membrane upon addition of a permeation enhancer (oleic acid) to the formulation.
The pre-cut Strat-M membrane disc can be removed from its pouch and loaded into a Franz cell to begin testing, as shown in Figure 4.
Strat-M membrane is a synthetic, non-animal based model* for transdermal diffusion testing that is predictive of diffusion in human skin without lot-to-lot variability, safety and storage limitations.
The Strat-M synthetic membrane, pictured in Figure 1, is an ultrafiltration membrane composed of polyether sulfone. Multiple layers of the membrane create morphology similar to human skin. Membrane layers are increasingly more porous and open and also increasingly larger in thickness. The membrane includes a top layer supported by a porous substructure bound to a non-woven fabric support. The porous structure is impregnated with a proprietary blend of synthetic lipids, imparting additional skin-like properties to the synthetic membrane. Watch the video on how the Strat-M membrane is breaking the barriers to predicting diffusion in human skin.
Performance data indicate that diffusion through Strat-M membrane is predictive of diffusion through human skin for a wide range of active pharmaceutical ingredients (API), cosmetic actives, formulations, personal care products, pesticides and chemicals. In most cases, the correlation of Strat-M membrane to human skin is much better than that of animal skin models commonly used for in vitro testing of transdermal formulations. Furthermore, because it is a synthetic test model with low variability and no special storage or hydration requirements, Strat-M membrane simplifies experimental design and data analysis.
Whether safety testing a slowly diffusing sunscreen active, or optimizing a rapidly diffusing NSAID formulation for pain relief, Strat-M membrane provides the versatility to generate meaningful data. Results indicate that the Strat-M synthetic membrane can be successfully used in place of human or animal skin for in vitro diffusion studies to provide meaningful and reproducible information about permeation characteristics of a range of compounds and formulations. A comparison of the transdermal diffusion rates for human skin and Strat-M for six different compounds is shown in Figure 2.
Addition of an enhancer to a formulation (see Figure 3) leads to higher diffusion of analyte through Strat-M membrane, similar to enhancer effects seen in human cadaver skin. The synthetic membrane can, therefore, be used in evaluating formulations as well as for compound screening. To find out how well the Strat-M membrane will work, access the Compound Correlation Tool.
Unlike skin models, Strat-M membrane is shelf-stable and does not require any special storage considerations. Because the membrane arrives pretreated, time-consuming steps for hydration are not necessary. The pre-cut Strat-M membrane disc can be removed from its pouch and loaded into a Franz cell to begin testing, as shown in Figure 4. To learn more about Strat-M, as well as to request more information or a trial pack, contact EMD Millipore.
*For research use only. Not for use in diagnostic procedures.
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