Gastrointestinal tract administration

Delivery of peptides and proteins via the gastrointestinal tract has not been successful because of poor penetration through the intestinal epithelium and high levels of proteolytic activity in the gastrointestinal tract. Liposomal encapsulation of proteins and peptides will not improve the efficiency and capacity of this absorption pathway considerably (e.g., Ryman et al., 1982 Machy and Leserman, 1987 Weiner and Chia-Ming Chiang, 1988). These difficulties in delivery via the oral route caused the parenteral route to remain the preferred route for the administration of therapeutic peptides... 

Diisopropyl methylphosphonate was absorbed from the gastrointestinal tract of mink, rats, mice, dogs, and cattle after oral administration of the [14C]-radiolabeled compound as indicated by the appearance of the radiolabel in the blood after exposure (Bucci et al. 1992 Hart 1976 Ivie 1980). Quantitative measurements of absorption can only be approximated (Hart 1976 Ivie 1980). 

After doses of 10 mg/kg/day in a cow and 225 mg/kg in male mice, rats, and dogs (fasted for 18 hours prior to administration of diisopropyl methylphosphonate), approximately 90% of the diisopropyl methylphosphonate was absorbed from the gastrointestinal tract. This estimate is based on the small percentage of the label found in the feces in the 2-3-day period after dosing and the 84-97% excreted in the urine (Hart 1976 Ivie 1980). 

Studies of excretion in animals following oral administration of TOCP and tri-para-cresyl phosphate suggest that organophosphate esters found in hydraulic fluids may be extensively absorbed by the gastrointestinal tract (Abou-Donia et al. 1990a, 1990b Kurebayashi et al. 1985 Suwita and Abou-Donia 1990). 

Returning to Fig. 6, it can be seen that the oral administration of two 15-mg tablets of propantheline 1.5 hours before atenolol delayed the rate of availability of this p-blocker, while increasing its extent of availability [11]. This increased extent might be due to more complete dissolution of the drug, resulting from its increased time in the gastrointestinal tract. 

New routes of administration transmucosal specific regional uptake in gastrointestinal tract New pattern of drug release bolus/flrst order/pulsatile feedback control disease-related release of drug... 

Babinska I., Rotkiewicz T. and Otrocka-Domagala I. (2005). The effect of Lactobacillus acidophilus and Bifidobacterium spp. administration on the morphology of the gastrointestinal tract, liver and pancreas in piglets . Pol J Vet Sci, 8(1), 29-35. 

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