Abstract
The gastrointestinal transition of mucoadhesive drug carriers may be affected by food intake, since food changes the physiological conditions of the gastrointestinal tract, and the food content itself is a physical obstruction for the drug carriers. Here we investigated the effects of food intake on the gastrointestinal transition and mucoadhesive function of submicron-sized chitosan-coated liposomes (ssCS-Lip). The stomach and small intestine were removed after oral administration of ssCS-Lip and non-coated liposomes (ssLip) containing fluorescent dye to fasted or fed rats, and retentive properties were quantitatively confirmed by measuring the amount of dye in each part of the gastrointestinal tract. Both types of liposome were retained in the stomach at approx. 40% in the fed rats at 1 h after oral administration, whereas transitions in the intestine were reduced compared to the fasted rats. However, the transition of ssCS-Lip in intestine was prolonged compared to ssLip even, in the fed state. The mucoadhesive behavior of ssCS-Lip was evaluated by confocal laser scanning microscopy. The ssCS-Lip tended to penetrate into the mucosal part of the intestine, and in addition, ssCS-Lip was detected in the basolateral side in both conditions, and therefore the mucopenetrative function was confirmed in the fed condition. Based on these results, we confirmed that ssCS-Lip shows a predominant gastrointestinal transition and mucopenetration, even after food intake.
