Lectins in drug delivery: a study of the acute local irritancy of the lectins from Solanum tuberosum and Helix pomatia

Lectins are proteins or glycoproteins of non-immune origin capable of bindi ng to one or more specific sugar residues. The potential for using lectins as a means of 'anchoring' a drugs delivery system to the mucosal surfaces o f the eye has been investigated in previous work, with the lectins from Sol anum tuberosum and Helix pomatia showing particular promise. In this study the acute local dermal irritancy of these lectins, in terms of their potent ial to cause inflammation and tissue necrosis, was investigated. After an i nitial study in terminally anaesthetised animals (to ensure no gross toxici ty was evident), five male New Zealand white rabbits from the same litter w ere briefly anaesthetised and Evans blue injected intravenously as a marker of inflammation. Sterile lectin solutions in normal saline at a range of c oncentrations from 50 to 500 mu g ml(-1) were prepared and 50-mu l volumes injected intradermally at 18 sites across a shaved area of each rabbit's ba ck. The rabbits were then allowed to regain consciousness. There was no evi dence of tissue necrosis, oedema or Evans blue infiltration with any of the lectin solutions administered. The rabbits did not display any signs of di scomfort such as scratching or continued grooming throughout the experiment . Histological examination of the injection sites revealed little sign of a ny inflammation, such as heterophil migration, oedema or tissue damage. It was concluded that these lectins demonstrate minimal acute irritancy, and w ill, therefore, be taken forward for formulation and in vivo studies. (C) 1 999 Elsevier Science B.V. All rights reserved.