Intestinal properties

Various other properties intestinal antiseptic (932, 933), fungicide (934, 935), insecticide (895. 898), coccidiostatic activity (936), car-cinolytic activity (937), radioprotective activity (938), antimutagenic activity (939, 940). 

Salts of acetarsone are used in the treatment of intestinal amoebiasis, vaginal trichomoniasis, and necrotizing ulcerative gingivitis (Vincent s angina). The diethylamine salt (acetylarsan [534-33-8]) has antisyphilitic properties. Because of toxicity problems, safer dmgs have been developed. Oral LD q in rabbits is 150 mg /kg. 

Health and Safety Factors. The strontium ion has a low order of toxicity, and strontium compounds are remarkably free of toxic hazards. Chemically, strontium is similar to calcium, and strontium salts, like calcium salts, are not easily absorbed by the intestinal tract. Strontium carbonate has no commonly recognized hazardous properties. Strontium nitrate is regulated as an oxidizer that promotes rapid burning of combustible materials, and it should not be stored in areas of potential fire hazards. 

Important physical and functional properties of maltose and maltose symps include sweetness, viscosity, color stabiUty, humectancy, freezing point depression, and promotion of beneficial human intestinal microflora growth. Maltose possesses ca 30—40% of the sweetness of sucrose in the pure state (32). 

The use of a bioadhesive, polymeric dosage form for sustained dehvery raises questions about swallowing or aspirating the device. The surface area is small, and patient comfort should be addressed by designing a small (less than 2 cm ), thin (less than 0.1 mm (4 mil) thick) device that conforms to the mucosal surface. The buccal route may prove useful for peptide or protein dehvery because of the absence of protease activity in the sahva. However, the epithelium is relatively tight, based on its electrophysiological properties. An average conductance in the dog is 1 mS/cm (57) as compared to conductances of about 27 and 10 mS/cm in the small intestine and nasal mucosa, respectively (58,59) these may be classified as leaky epitheha. 

The genes encoding the polypeptide backbones of a number of mucins derived from various tissues (eg, pancreas, small intestine, trachea and bronchi, stomach, and salivary glands) have been cloned and sequenced. These studies have revealed new information about the polypeptide backbones of mucins (size of tandem repeats, potential sites of N-glycosylation, etc) and ultimately should reveal aspects of their genetic control. Some important properties of mucins are summarized in Table 47-8. 

Saponins and phenolics also have anti-microbial properties (Chung et ah, 1998) and have been associated with reduced rumen functions (Klita et al., 1996 Reed, 1995), thereby limiting the nutrient quality of forages. Also, carbohydrate complexes with hgnins and other compounds reduce carbohydrate utilization by rumen bacteria (Cornu et al., 1994). The influence of such anti-microbials on rumen functions can affect small intestine characteristics by altering nutrient concentrations (Barry and McNabb, 1999). 

Milieu conditions in gastrointestinal tract can influence the pectin structure and properties. Under the acid conditions of the stomach (pH 2-4) extraction of pectin from plant cell walls and hydrolysis of side chains can occur. In small intestine (pH 5-6) -elimination of main chains or de-esterification seems to be possible. In caecum and colon (pH 6-8) a strong fermentation of pectin takes place causing depolymerization to oligomers and leading to formation of short chain fatty acids and gases. The presence of OligoGalA is not yet clarified. 

Like other xenobiotics, cannabinoids also undergo extensive metabolism in the human body to increase their hydrophihc properties for a facihtated ehmination. The metaboHsm of A9-THC has been very well investigated. More than 100 metabolites of A9-THC are known [99] and a good overview of the most important human metaboHtes is given in [100]. MetaboHsm takes place mainly in hepatic microsomes, but also in intestines, brain. 

Polar surface area (PSA) - defined simply as the part of a molecular surface that is polar - is probably, together with the octanol-water partition coefficient, one of the most important parameters used to characterize the transport properties of drugs. PSA has been shown to provide very good correlations with intestinal... 

Palm, K., Stenberg, P., Luthmann, K., Artursson, P. Polar molecular surface properties predict the intestinal absorption of drugs in humans. Pharm. Res. 1997, 14, 568-571. 

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