Hydrocortisone release from tablets based on bioresorbable poly(ether-ester-urethane)s

Bioresorbable linear poly(ether-ester-urethane)s with different hydrophilic characteristics were synthesized from triblock copolymers of poly(¿-caprolactone)-poly(ethylene oxide)-poly(¿-caprolactone) (PCL-PEO) as macrodiols, and L-lysine diisocyanate (LDI) or hexamethylenediisocyanate (HDI) were used as the required diisocyanates. Macrodiols were obtained by ring-opening polymerization (ROP) of ¿-caprolactone (CL). Polyurethanes were synthesized by the reaction of the triblock copolymers with LDI or HDI in solution using stannous 2-ethylhexanoate as catalyst. Polyurethane tablets were fabricated and investigated as prospective drug delivery systems. The effect of the PEO content on the polymers¿ performance as drug carriers was evaluated. It was found that water provoked more swelling and erosion of polymers with higher contents of PEO. The hydrocortisone release profiles were analyzed using the Ritger-Peppas approximation. An anomalous release behaviour (values of n higher than 0.5) was found for most of the analyzed samplesWe acknowledge the financial support provided by the Consejo Nacional de Ciencia y Tecnología (CONACYT), México, Ministerio de Ciencia e Innovación (MAT2014-52644-R), Spain, and the Universidad de Guanajuato, México. Authors are indebted to Dr. Guillermo Mendoza-Diaz (Universidad de Guanajuato) for his helpful discussions. The authors thank Salvador López Morales (Instituto de Investigaciones en Materiales, UNAM) for GPC-MALLS analysis. The authors wish to thank the Directorate for Research Support and Postgraduate Programs at the University of Guanajuato for their support in the editing of the English-language version of this article.Peer Reviewe

II. Pesquerías continentales de Colombia: cuencas del Magdalena-Cauca, Sinú, Canalete, Atrato, Orinoco, Amazonas y vertiente del Pacífico

Con esta nueva publicación, el Instituto de Investigación de Recursos Biológicos Alexander von Humboldt quiere darle continuidad a la línea de investigación sobre la biodiversidad acuática continental de Colombia, vista desde la perspectiva no solo de su conocimiento básico y conservación, sino de la importancia que tiene esta enorme diversidad de peces en el contexto del uso de los recursos hidrobiológicos y pesqueros, y de su importancia en la seguridad alimentaria e incluso en la economía del país.Bogotá, D. C.Instituto de Investigación de Recursos Biológicos Alexander von Humbold