Silicone polymers in scar remediation: The role of migration of oligomers through stratum corneum

A cross-linked silicone gel for burns scar rehabilitation has been analyzed to determine the oligomeric species that may migrate from the gel into skin. From MALDI-MS (matrix assisted laser desorption ionization-mass spectrometry) these were shown to be hydroxyl-terminated linear oligomers with a mass of up to 2100 Da. The migration of the extracted oligomers through stratum corneum has been determined by breakthrough times using ATR-FTIR (attenuated total reflection Fourier-transform infrared) spectroscopy. The upper value of the estimated diffusion coefficient of 2.5 x 10(-9) cm(2) s(-1), determined from a breakthrough time of 31 h, is similar to that of large hydrophobic solutes, but penetration times from the silicone gel are low (7-10 days) due to the lower concentration of oligomers partitioning into the lipid bilayer of the skin in an aqueous environment.