Gastroretentive dosage forms.

摘要: This article begins with a review of gastric emptying, small intestine transit, and colonic transit drug delivery systems special attention paid to the different physiological processes involved in stomach emptying cut-off size nondigestible solids for passage through gastroduodenal junction during digestive phase. Then, proposed means prolonging residence time (GRT) are reviewed analyzed emphasis on floating (F) dosage forms. The following discussed: use passage-delaying agents, large single-unit forms, bioadhesive systems, 'heavy' pellets, buoyant In section devoted influence turnover intestinal mucus gel layer performance mucoadhesive preparations is pointed out explain poor results obtained humans such peroral products. specifically designed apparatus measuring total force acting vertically an object immersed liquid presented as methodology selecting optimized formations vitro. Scintigraphic studies described nonfasting human volunteers either upright or supine posture, who concurrently were given one F nonfloating (NF) hydrophilic matrix capsules same size, three sizes (small, medium, large). subjects, forms stayed continuously above contents irrespective their whereas NF ones sank rapidly after administration never rose back surface thereafter. Consequently, show prolonged more reproducible GRTs compared ones. significance extent this prolongation most marked units (p 0.05). Moreover, there no significant difference between mean small, >0.05). indirectly confirms that intragastric buoyancy main process determining GRT protecting them from random related antral peristaltism. Thus, depends mainly occurrence end point digestion. To contrary, lasting retention only dependent. It appeared systematically but not all medium (mean 0.05) because remain anywhere lesser greater curvatures stomach. position does protect when they move distally toward pylorus. vary according still increase form