MIGRATION OF ADHESIVE AND NONADHESIVE PARTICLES IN THE RAT INTESTINE UNDER ALTERED MUCUS SECRETION CONDITIONS

The migration rate of adhesive (polycarbophil) and nonadhesive (Eudrag it RL-100) particles was studied in the small and large intestine of t he anesthetized rat under altered mucus secretion conditions accomplis hed by cholinergic stimulation (a previously developed in situ model w hich distinctly accounts for the effect of regional changes in mucus t urnover rate on mucoadhesion in the digestive tube of the rat). It was found that in the proximal jejunum the relative recovery time (RRT) o f adhesive particles, but not nonadhesive particles, was decreased by carbachol stimulation. However, adhesive particles agglomerated a shor t while after their administration into this organ. In the colon RRT o f both adhesive and nonadhesive particles decreased in a similar manne r as the mucus secretion increased. It is concluded that, in the rat, interactions between intestinal mucus layer and adhesive and nonadhesi ve particles are similar. The corresponding similarity in the intestin al transit time for both types of particles raises doubts about the ad vantage of nonspecific adherence in the design of oral prolonged-relea se dosage forms.