DRUG ABSORPTION SITES IN THE GASTROINTESTINAL-TRACT AND DOSAGE FORMS FOR SITE-SPECIFIC DELIVERY

The authors firstly review the literature dealing with drug absorption sites in the gastrointestinal tract. Descriptions are given of the me thods used in determining the location of these sites; and the advanta ges and disavantages of each method are critically discussed. The resu lts obtained concerning the absorption sites of the drugs used in the in vivo methods studied are given in a tabular form and several factor s influencing drug absorption are briefly reported. Mechanisms of drug absorption in the human body and their influence on absorption sites are examined. Finally, there is a discussion of various dosage forms w hich are used for targetting drug absorption to specific sites.