Enhancement Effect of Trypsin on Permeation of Clindamycin Phosphate Through Third-degree Burn Eschar

Antimicrobial therapy remains to be the most important method of wound infection treatment. Systemically administered antimicrobials may not achieve therapeutic level in wound. On the other hand, in the absence of surgical debridement (due to any reason), most topically applied antimicrobials cannot penetrate the wound in therapeutic amount due to the presence of eschar. Burn eschar is a proteinous structure with some lipid components in which proteins seems to play an important role in the barrier effects of eschar. Therefore, in this study the effect of protein-acting enhancer (trypsin) on permeation of hydrophilic model drug (clindamycin phosphate) was investigated. To perform this investigation, permeation of saturated clindamycin phosphate was studied at 32°C through trypsin-treated and untreated eschar samples for 12 h using home-made static diffusion cells. Third-degree burn eschar samples were separated at the time of surgical debridement (7-14 days post burn) from burned patients. Before each experiment, eschar was hydrated for 12 h and samples were then treated with trypsin solution (1%, w/v) for 4 and 24 h. Clindamycin was measured by a HPLC method developed here. Results showed that after trypsin-treatment for 4 and 24 h, clindamycin phosphate permeation flux was increased significantly by about 1.5 and 2 times and permeation lag-time was decreased by about 2 and 1.3 times respectively. The present results show that permeation of drugs through burn eschar can be increased considerably by trypsin.