Influence of Injection Application on the Sol-Gel Phase Transition Conditions of Polysaccharide-Based Hydrogels.

Polysaccharide matrices formed via thermoinduced sol-gel phase transition are promising systems used as drug carriers and minimally invasiveness scaffolds in tissue engineering. The strong shear field generated during injection may lead to changes in the conformation of polymer molecules and, consequently, affect the gelation conditions that have not been studied so far. Chitosan (CS) and hydroxypropyl cellulose (HPC) sols were injected through injection needles (14 G-25 G) or sheared directly in the rheometer measuring system. Then the sol-gel phase transition conditions were determined at 37 °C using rheometric, turbidimetric, and rheo-optical techniques. It was found that the use of low, respecting injection, shear rates accelerate the gelation, its increase extends the gelation time; applying the highest shear rates may significantly slow down (HPC) or accelerate gelation (CS) depending on thixotropic properties. From a practical point of view, the conducted research indicates that the use of thin needles without preliminary tests may lead to an extension of the gelation time and consequently the spilling of the polymeric carrier before gelation. Finally, an interpretation of the influence of an intensive shear field on the conformation of the molecules on a molecular scale was proposed.

Utilidad del conocimiento de la mucosa oral como órgano blanco para inducir farmacoinmunoterapia. revisión sistemática / Knowledge of oral mucosa as a tarjet organ to induce pharma- immunotherapy

La mucosa bucal ha sido utilizada en Medicina como órgano blanco para inducir moléculas farmacológicas, inmunomoduladoras y vacunas. Tales prácticas se han basado en "investigaciones científicas avaladas por sus resultados" y en la "Medicina basada en la evidencia". Hoy en día ambas terapias se aplican como prácticas correctas. Sin embargo, es posible establecer la pregunta siguiente: ¿Son conocidas, previamente, las características específicas de la mucosa oral y sus variantes? Para obtener una respuesta satisfactoria, se presenta una revisión sistemática de calidad, consultando en la bibliografía las cualidades específicas de la mucosa bucal.(AU)

Oral mucosa have been used in Medicine as a tarjet organ to induce pharmacological, immuno modulated molecules and vaccines .Such practices have been based on the scientific investigations results, and by "Evidence Based Medicine (EBM)". Today both therapies are applied as corrected practice. However, it´s possible to establish the following question: ¿There are known, previously, the specific characteristics of oral mucosa and its variants which could benefit or interfere the results? In order to identify relevant studies about this request, it´s present a systematic review of quality, consulting .specific bibliography.(AU)