Clindamycin Phosphate Absorption from Nanoliposomal Formulations through Third-Degree Burn Eschar

BACKGROUND

It has been shown that topical nanoliposomal formulations improve burn healing process. On the other hand, it has been shown that liposomal formulations increase drug deposition in the normal skin while decrease their systemic absorption; there is not such data available for burn eschar. Present investigation studies permeation of clindamycin phosphate (CP) through burn eschar from liposomal formulations to answer this question. In this investigation, permeation of CP through fully hydrated third-degree burn eschar was evaluated using solution, normal nanoliposomes and ultradeformable nanoliposomes.

METHODS

Liposomal CP were prepared by thin-film hydration and characterized in terms of size, size distribution, zeta potential, encapsulation efficiency and short-time stability. Then the effect of liposomal lipid concentration on CP absorption was investigated.

RESULTS

The permeability coefficient ratio (liposome/solution) and permeation lag-time ratio (liposome/solution) of CP through burn eschar at 20 Mm lipid concentration were 0.81±0.21 and 1.19±1.30 respectively, indicating the retardation effects of liposomes. Data also showed that increasing liposomal lipid concentration from 20 to 100 mM, clindamycin permeation decreased by about 2 times. There was no difference between normal liposome and ultradeformable liposome in terms of clindamycin absorption.

CONCLUSION

Nanoliposomes could decrease trans-eschar absorption of CP, in good agreement with normal skin data, and might indicate CP deposition in the eschar tissue.

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.