Evaluation of novel nystatin nanoemulsion for skin candidosis infections.

One of the most common fungal skin infections is candidosis. Topical application of drugs at the pathological sites offers potential advantage of direct drug delivery to the site of action. The main aim of this work was to evaluate an optimal nystatin nanoemulsion for topical application avoiding undesirable side effects as systemic absorption and toxicity. Surface morphology and droplet size distribution of nystatin nanoemulsion was determined by transmission electronic microscopy and dynamic light scattering. Vertical diffusion Franz-type cells and high-performance liquid chromatography were used to perform the in vitro release and ex vivo human skin permeation studies. Transdermal permeation parameters were estimated from the permeation values using different theoretical approaches. Microbiological studies were performed to evaluate the antifungal effect. Nanoemulsion exhibited a spherical shape with smooth surface and mean droplet size between 70 and 80 nm. The pharmacokinetic release showed the nanoemulsion is faster than commercial ointment Mycostatin(®) improving the potential therapeutic index. Permeation studies demonstrated nystatin was not absorbed into systemic circulation and the retained amount in the skin was sufficient to ensure an antifungal effect. This antifungal effect was higher for nystatin loaded nanoemulsion than nystatin itself. A therapeutic improvement of the nystatin nanoemulsion treatment compared with the classical ones was achieved.

Pore geometry influences growth and cell adhesion of infrapatellar mesenchymal stem cells in biofabricated 3D thermoplastic scaffolds useful for cartilage tissue engineering.

The most pressing need in cartilage tissue engineering (CTE) is the creation of a biomaterial capable to tailor the complex extracellular matrix of the tissue. Despite the standardized used of polycaprolactone (PCL) for osteochondral scaffolds, the pronounced stiffness mismatch between PCL scaffold and the tissue it replaces remarks the biomechanical incompatibility as main limitation. To overcome it, the present work was focused in the design and analysis of several geometries and pore sizes and how they affect cell adhesion and proliferation of infrapatellar fat pad-derived mesenchymal stem cells (IPFP-MSCs) loaded in biofabricated 3D thermoplastic scaffolds. A novel biomaterial for CTE, the 1,4-butanediol thermoplastic polyurethane (b-TPUe) together PCL were studied to compare their mechanical properties. Three different geometrical patterns were included: hexagonal (H), square (S), and, triangular (T); each one was printed with three different pore sizes (PS): 1, 1.5 and 2 mm. Results showed differences in cell adhesion, cell proliferation and mechanical properties depending on the geometry, porosity and type of biomaterial used. Finally, the microstructure of the two optimal geometries (T1.5 and T2) was deeply analyzed using multiaxial mechanical tests, with and without perimeters, µCT for microstructure analysis, DNA quantification and degradation assays. In conclusion, our results evidenced that IPFP-MSCs-loaded b-TPUe scaffolds had higher similarity with cartilage mechanics and T1.5 was the best adapted morphology for CTE.

Development of a liquid chromatographic method for the quantification of paromomycin. Application to in vitro release and ex vivo permeation studies.

We have developed a reversed phase high performance liquid chromatography pulsed amperometric detection (RPHPLC-PAD) method for the determination of paromomycin. It is sensitive, repeatable, and selective without the pretreatment step. Trifluoroacetic acid-water was utilized as the eluent and detected by PAD under NaOH alkaline conditions. The paromomycin detection limit (S/N=3.3) was 2µgmL(-1) and the quantification limit (S/N=10) was 6µgmL(-1). Coefficients of linear regression were higher than 0.99 for concentrations between 6.25 and 200µgmL(-1). The intra and inter-day precision (RSD) was less than 6.5%. The average recoveries were 97.53-102.01%. The proposed HPLC-PAD method presented advantageous performance characteristics and it can be considered suitable for the evaluation of paromomycin loaded nanogel formulation in ex vivo permeation and in vitro release studies.

Novel microparticulate systems for the vaginal delivery of nystatin: development and characterization.

To develop more effective antifungal microparticulate therapeutic systems for the treatment of Candida vaginitis, microparticles containing nystatin were elaborated by emulsification/internal gelation method. Three types of microparticles were successfully prepared, alginate microparticles, chitosan and poloxamer 407 coated alginate microparticles. DSC and FT-IR studies were performed to test the efficacy of the method. After physicochemical characterization, mean particle sizes ranged from 36.088 µm to 56.146 µm. The encapsulation efficiency was found to be similar for alginate and chitosan coated microparticles and lower for poloxamer 407 coated. Optimal mucoadhesive properties in all kind of microparticles where exhibited. Release studies showed the best kinetic parameters for poloxamer 407 coated microparticles. After ex vivo permeation studies through porcine vaginal mucosa, and determination of the amount of nystatin retained as well as microbiologic studies performed, it could be inferred that the developed microparticulate systems offered an antifungal effect against Candida albicans without toxic systemic absorption.