Influence of cryopreservation methods of ex vivo rat and pig skin on the results of in vitro permeation test

In vitro permeation test (IVPT) is a frequently used method for in vitro assessment of topical preparations and transdermal drug delivery systems. However, the storage of ex vivo skin for IVPT remains a challenge. Here, two cryopreservation media were chosen to preserve rat and pig skin at -20 & DEG;C and -80 & DEG;C for further IVPT, namely, 10 % DMSO and 10 % GLY. The skin viability test confirmed that the skin protective capacity of 10 % DMSO and 10 % GLY was almost equal. The results of skin viability and IVPT showed that the skin viability and permeability of rat skin in 10 %DMSO or 10 % GLY were maintained for at least 7 and 30 days at -20 & DEG;C and -80 & DEG;C compared to fresh skin, respectively; in contrast, those of porcine skin were just maintained for <7 days at -20 & DEG;C and -80 & DEG;C. These results indicated that ex vivo skin for IVPT preserved at -80 & DEG;C in 10 % DMSO or 10 % GLY was optimal. Furthermore, skin permeability was independent of skin barrier integrity. Our study provides reference conditions for preserving IVPT skin, and skin viability can be a potential indicator of IVPT skin.

Automated summary

In vitro permeation test (IVPT) is commonly used for evaluating topical preparations and transdermal drug delivery systems. However, the storage of ex vivo skin for IVPT is challenging. This study investigated the efficacy of two cryopreservation media, 10% DMSO and 10% GLY, for preserving rat and pig skin at -20°C and -80°C, and found that -80°C storage in 10% DMSO or 10% GLY was optimal for maintaining skin viability and permeability. The results also suggested that skin viability could serve as a potential indicator for IVPT skin.