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 anabundant, low cost, biodegradable, biocompatible and non-toxic polysaccharide with good membrane and gelforming properties. Pharmaceutical formulations containing estradiol (E2) are used by women for the treatment ofmenopausal symptoms and menstrual disorders. This female hormone is also a contaminant present in wastewatereffluent. The study deals with the analysis of the interaction between E2 and CHT, in particular the influence of crosslinkingdensity of CHT membranes on swelling, sodium content and E2 permeation. CHT powder was characterizedfor its degree of deacetylation (77 %) and viscosimetric molecular weight (600KDa). CHT membranes were obtainedby a casting/solvent evaporation method and cross-linking with sodium tripolyphosphate (TPP). The cross-linkingconditions were: an aqueous solution of TPP 5 % w/v and cross-linking time: 5 to 55 min. Sodium content increasedwith increasing cross-linking time, in a logarithmic manner, from 11.61 to 40.43 μg mg-1 of membrane. Membranesexhibited 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-2h-1) with the increase in cross-linking duration from 15 to 55 min. One explanation for these results could be thealtered type of linkage between CHT and TPP (because of the prolongation of the cross-linking reaction), or theexistence 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 wasthe membrane with the lowest cross-linking time which showed the higher equilibrium water content and a higher fluxof E2 compared with the others membranes, this could be attributed to improper cross-linking. This knowledge couldhave a great potential application in the recycling of wastewater effluents using CHT membranes for the removal ofE2 (a currently contaminant) or in the pharmaceutical industry for the development of transdermal delivery systems.