Estradiol permeation studies in chitosan membranes. Effects of cross-linking time

LUCIANO MENGATTO, JULIO LUNA, MARÍA INÉS CABRERA

Rosario

Taller; 1º Taller de Órganos Artificiales, Biomateriales e Ingeniería de Tejidos (BIOOMAT); 2009

Universidad Nacional de Rosario - Sociedad Latinoamericana de Biomateriales, Ingeniería de Tejidos y Órganos Artificiales

Chitosan (CHT) is an abundant, low cost, biodegradable, biocompatible and non-toxic polysaccharide with good membrane and gel forming properties. Pharmaceutical formulations containing estradiol (E2) are used by women for the treatment of menopausal symptoms and menstrual disorders. This female hormone is also a contaminant present in waste water effluent. The study deals with the analysis of the interaction between E2 and CHT, in particular the influence of crosslinking density of CHT membranes on swelling, sodium content and E2 permeation. CHT powder was characterized for its degree of deacetylation (77 %) and viscosimetric molecular weight (600KDa). CHT membranes were obtained by a casting/solvent evaporation method and cross-linking with sodium tripolyphosphate (TPP). The cross-linking conditions were: an aqueous solution of TPP 5 % w/v and cross-linking time: 5 to 55 min. Sodium content increased with increasing cross-linking time, in a logarithmic manner, from 11.61 to 40.43 μg mg-1 of membrane. Membranes exhibited an increment in equilibrium water content (0.44 to 0.647 g g-1) and flux of E2 (2.458 to 12.743 μg cm-2/h-1) with the increase in cross-linking duration from 15 to 55 min. One explanation for these results could be the altered type of linkage between CHT and TPP (because of the prolongation of the cross-linking reaction), or the existence of a significant correlation between the hydrophilicity of the membrane and the low water solubility of E2. Hydrophobic compound are less solvated and can enter more easily into the membrane pores. The exception was the membrane with the lowest cross-linking time which showed the higher equilibrium water content and a higher flux of E2 compared with the others membranes, this could be attributed to improper cross-linking. This knowledge could have a great potential application in the recycling of waste water effluents using CHT membranes for the removal of E2 (a currently contaminant) or in the pharmaceutical industry for the development of transdermal delivery systems.