Enhanced in vivo delivery of 5-fluorouracil by ethosomal gels in rabbit ear hypertrophic scar model.

Applying Ethosomal Gels (EGs) in transdermal drug delivery systems has evoked considerable interest because of their good water-solubility and biocompatibility. However, there has not been an explicit description of applying EGs as a vehicle for hypertrophic scars treatment. Here, a novel transdermal EGs loaded with 5-fluorouracil (5-FU EGs) was successfully prepared and characterized. The stability assay in vitro revealed that 5-FU EGs stored for a period of 30 days at 4 ± 1 °C had a better size stability than that at 25 ± 1 °C. Furthermore, using confocal laser scanning microscopy, EGs labeled with Rhodamine 6 G penetrated into the deep dermis of the hypertrophic scar within 24 h in the rabbit ear hypertrophic model suggested that the EGs were an optional delivery carrier through scar tissues. In addition, the value of the Scar Elevation Index (SEI) of 5-FU EGs group in the rabbit ear scar model was lower than that of 5-FU Phosphate Buffered Saline gel and Control groups. To conclude, these results suggest that EGs delivery system loaded 5-fluorouracil is a perfect candidate drug for hypertrophic scars therapy in future.

Preparation of ethosomes and deformable liposomes encapsulated with 5-fluorouracil and their investigation of permeability and retention in hypertrophic scar.

With the aim of comparing scar penetration efficiency and retention between ethosomes and deformable liposomes both encapsulated with 5-fluorouracil (5-FU), the 5-FU ethosomal suspensions (5-FU ES, 81.74 +/- 9.37 nm) and the 5-FU Deformable Liposomal Suspensions (5-FU DS, 73.7 +/- 9.45 nm) were prepared respectively by Touitou method and Cevc method, their sizes were determined by Particle Sizer System (PSS), and their entrapment Efficiency (EE) was detected by ultracentrifugation and microcolumn centrifugation. Their transdermal delivery experiments were done in hypertrophic scars in vitro. The permeated amount of 5-FU and retention contents of 5-FU were both calculated by High Performance Liquid Chromatography (HPLC). Fluorescence intensities of ES and DS labeled with Rodanmin 6GO (Rho) were measured by Laser Scanning Microscopy (LSM). The control groups such as the 5-FU and empty ethosomal vesicles (5-FU + EEV), the 5-FU and empty deformable liposomal vesicles (5-FU + EDV) and 5-FU PBS Solution (5-FU Sol) were set up. Results showed that, prepared 5-FU ES was 81.74 +/- 9.37 nm in size, 5-FU DS was 73.7 +/- 9.45 nm, EE of 5-FU ES was 10.95%, EE of 5-FU DS was 15.05%. Within 24 hours, in the group of 5-FU ES, the penetration amount of 5-FU in scar was 14.12 +/- 0.1 microg/mL/cm2, the retention contents of 5-FU was 10.74 +/- 1.17 microg/cm2, and the fluorescence intensity of Rho in hypertrophic scar tissues were 182 +/- 18.3; in the group of 5-FU DS: the penetration amount of 5-FU was 12.35 +/- 1.21 microg/mLcm2; the retention contents of 5-FU was 17.48 +/- 0.82 microg/cm2, and the fluorescence intensity of Rho was 241.45 +/- 7.63; there existed statistical difference between penetration amount in the group of 5-FU ES and that in the group of 5-FU DS as well as control groups (P < 0.05, P < 0.01), the penetration amount in the group of ES is markedly higher than DS group or control groups. Conversely, the retention contents of 5-FU and the fluorescence intensity of Rho in DS group were higher than those in ES group and control groups (P < 0.05, P < 0.01). In conclusion, both ES and DS could deliver 5-FU into the hypertrophic scars effectively. ES has better permeability of 5-FU than DS, DS has higher entrapment efficiency of 5-FU, and more 5-FU deposition in hypertrophic scar than ES. We should select ES or DS encapsulated with 5-FU according to clinical demand for hypertrophic scar therapy.

Orientated Guidance of Peripheral Nerve Regeneration Using Conduits with a Microtube Array Sheet (MTAS).

Material surface topography has been shown to affect the biological behavior of cells in vitro; however, the in vivo effect on peripheral nerve regeneration has not been explored. Here, we studied the potential of a microtube array sheet (MTAS) with a unique longitudinal surface topography to promote peripheral nerve regeneration efficiency, both in vivo and in vitro. Schwann cells, spinal cord motor neurons, and dorsal root ganglion neurons were seeded on the MTAS to study the effect of the construct on the biological properties and behaviors of neural cells. The MTAS guided the oriented migration of Schwann cells without affecting other critical biological properties, such as proliferation and neurotrophin expression. In addition, the MTAS guided the directed extension of neurites from both types of neurons. Next, we tested the capability of the MTAS to facilitate peripheral nerve regeneration by bridging a 10 mm sciatic nerve defect in rats with a nerve conduit equipped with an MTAS lining. The MTAS significantly promoted peripheral nerve regeneration, as suggested by the greater fiber caliber in the midconduit and the greater abundance of fibers in nerve segment distal to the conduit. Moreover, scanning electron microscopy (SEM) analysis suggested the orientated guidance of nerve regeneration by the MTAS, as indicated by the smaller eccentricity of the nerve fibers and the concordant arrangement of the collagen fiber in both the fibers and the matrix in the MTAS group. Our results collectively suggest that the conduits with the MTAS developed in this study have significant potential for facilitating peripheral nerve regeneration by modifying critical biological behaviors and guiding orientated nerve growth.