Preparation of Ulex europaeus lectin-gliadin nanoparticle conjugates and their interaction with gastrointestinal mucus

One approach to improve the bioavailability and efficiency of drugs consist s of the association of a ligand (i.e. lectins), showing affinity for biolo gical structures located on the mucosa surfaces, to nanoparticulate drug de livery systems. In this context, Ulex europaeus lectin-gliadin nanoparticle conjugates (UE-GNP) were prepared with the aim of evaluating their in vitr o bioadhesive properties. The lectin was fixed by a covalent procedure to g liadin nanoparticles by a two-stage carbodiimide method. Typically, the amo unt of bound lectin,was calculated to be similar to 15 mu g lectin/mg nanop article, which represented a coupling efficiency of similar to 16% of the i nitial lectin concentration. In addition, the activity of these conjugates was tested with bovine submaxillary gland mucin (BSM) and the level of bind ing to this mucin was always much greater with UE-GNP than with controls (g liadin nanoparticles). However, the presence of 50 mu mol fucose, which is the reported specific sugar for U. europaeus lectin, specifically inhibited the activity of these conjugates and, therefore, the UE-GNP binding to BSM was attenuated by 70%. These results clearly showed that the activity and specificity of U. europaeus lectin was preserved after covalent coupling to these biodegradable carriers. (C) 1999 Published by Elsevier Science B.V. All rights reserved.