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The aim of this work was to prepare an erythromycin (EM) microemulsion (EM- microemulsion) for transdermal EM delivery using isotropic mixtures of oil and aqueous phases. The prepared EM-microemulsion is a white dispersion, with a suitable viscosity for transdermal delivery. In stability experiments, the EM-microemulsion showed no marked change in appearance for up to 3 weeks at 25°C. In accelerated stability experiments at 37 and 60°C, however, precipitated crystalline EM particles were observed in the EM-microemulsion. Diffusion of EM into the skin exhibited a first order release profile. Fluorescein (FL)-microemulsion penetrated to the dermis layer of skin. In conclusion, we confirmed that EM-microemulsion could serve as an excellent transdermal carrier of EM. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

In this work, the in vivo biodegradation of, biocompatibility of, and host response to various topographic scaffolds were investigated. Randomly oriented fibrous poly(L-lactide) (PLLA) nanofibers were fabricated using the electrospinning technique. A PLLA scaffold was obtained by salt leaching. Both the electrospun PLLA nanofibers and the salt-leaching PLLA scaffolds formed three-dimensional pore structures. Cytotoxicity studies, in which rat muscle-derived stem cells (rMDSCs) were grown on electrospun PLLA nanofibers or the salt-leaching PLLA scaffolds, revealed that the rMDSCs cell count on the PLLA nanofibers was slightly higher than that on the salt-leaching PLLA scaffolds. An in vivo study was carried out by implanting the scaffolds subcutaneously into rats to test the biodegradation, biocompatibility, and host response at regular intervals over 0–4 weeks. The degradation of the PLLA nanofibers 1, 2, and 4 weeks after initial implantation was more extensive than that observed for the salt-leaching PLLA scaffolds. PLLA nanofibers seeded the growth of larger fibrous tissue masses due to in vivo cellular infiltration into the randomly oriented fibrillar structures of the PLLA nanofibers. In addition, the inflammatory cell accumulation in PLLA nanofibers was lower than that in the salt-leaching PLLA scaffolds. These results indicate that the electrospun PLLA nanofibers may serve as a good scaffold to elicit fibrous cellular infiltration, to minimize host response, and to enhance tissue–scaffold integration. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.