Assessment of the Effect of Microneedle Pretreatment on Permeation of Hydrophilic and Hydrophobic Drugs Through Burn Eschar

Purpose

Here, utilizing of microneedle roller as a physical enhancer of drug permeation through third-degree burn eschar has been investigated. This study was also conducted to investigate the effect of physicochemical properties of different drugs on permeation through perforated and unperforated eschar.

Method

1000 μm and 1500 μm height microneedle rollers were used to study the effect of microneedle pretreatment on permeation of diclofenac sodium, vancomycin hydrochloride, and sirolimus through human third-degree burn eschar. Optical microscopy and histological sectioning were used to visualize perforation and characterize the penetration depth, respectively. Franz-diffusion cells were utilized to study the permeation over 10 h.

Results

There were visible pores in eschar after treatment for both microneedle heights. Despite different physicochemical properties of drug models, microneedle rollers enhanced the permeation percentage through eschar in the range of 1.4 to 3.7 times for 1000 μm and 3.3 to 5.53 times for 1500 μm microneedle. Diclofenac as a molecule with the lowest MW and moderate log P had the highest permeation percentage in unperforated and perforated conditions. In the control condition, despite the higher MW of vancomycin compared to sirolimus, a higher percentage of vancomycin (about 2.7 times) permeated through eschar, indicating the higher permeability of hydrophilic drug in unperforated eschar. This behavior was also observed after eschar treatment with both heights of microneedle rollers.

Conclusion

Commercially available microneedle rollers enhance the drug permeation through eschar. Microneedle pretreatment has the potential to be used for burn management in situations where early eschar removal is not possible.