Absorption from gut

Occurs in all parts of the camphor tree Cin-namomum camphora. White solid, penetrating odour sublimes appreciably at ambient temperature readily volatile in steam. Teaspoonful of camphorated oil said to produce serious toxic effects in an adult. Children 1 g camphor profuse dermal, gastric and renal haemorrhaging. CNS deterioration, death. Liver and kidney fatty degeneration. Rapid absorption from gut lipid-soluble. Convulsions status epilepticus. 

DHCC synthesis and hence calcium absorption from gut ( i... 

Somatostatin Central nervous system, pancreatic delta cells, and enteroendocrine delta cells 1. Inhibits secretion of insulin, glucagon and PP (islets), and gastrin, secretin, GLP-1, and GLP-2 (in gut) 2. Reduces carbohydrate absorption from gut lumen 1. Luminal nutrients 2. GLP-1 3. GIP 4. PACAP 5. VIP 6. Beta-adrenergic stimulation... 

Historically, the use of xanthines has been hampered by poor aqueous solubiUty, rapid but highly variable metaboHsm, and the existance of a low therapeutic index. SolubiUty problems were partially solved by the preparation of various salt forms, eg, aminophylline. However, it was since recognized that the added base in aminophylline only increases solubiUty by increasing pH and thus does not affect the rate of absorption from the gut (65). Thus, in more recent medical practice, theophylline is commonly dispensed in anhydrous form and aminophylline is only recommended for iv adrninistration. 

Many of the phase 1 enzymes are located in hydrophobic membrane environments. In vertebrates, they are particularly associated with the endoplasmic reticulum of the liver, in keeping with their role in detoxication. Lipophilic xenobiotics are moved to the liver after absorption from the gut, notably in the hepatic portal system of mammals. Once absorbed into hepatocytes, they will diffuse, or be transported, to the hydrophobic endoplasmic reticulum. Within the endoplasmic reticulum, enzymes convert them to more polar metabolites, which tend to diffuse out of the membrane and into the cytosol. Either in the membrane, or more extensively in the cytosol, conjugases convert them into water-soluble conjugates that are ready for excretion. Phase 1 enzymes are located mainly in the endoplasmic reticulum, and phase 2 enzymes mainly in the cytosol. 

Pro-drugs (e.g. earbenicillin esters, ampicillin esters Fig. 5.2, Table 5.1) are hydrolysed by enzyme aetion after absorption from the gut mucosa to produce high blood levels of the aetive antibiotic, earbenicillin and ampicillin, respectively. 

There is some evidence that auranofin may also be biologically de-acetylated during its absorption from the gut [58]. It is unfortunate that so many in vitro studies to determine possible mechanisms for the anti-arthritic activity of auranofin have not considered (tetra) desacetyl-auranofin as the first likely active metabolite, with its far greater hydrophilicity than the administered auranofin (which is only a pro-drug). 

The physicochemical characteristics of the active ingredient in relation to the dosage form and the suitability for its intended purpose was discussed in several EPARs, particularly relating to the solubility characteristics and absorption from the gut. The compression characteristics were also mentioned in some EPARs. The possible effects of different polymorphs or evidence that only a single polymorph is used are addressed as appropriate. Different amorphous or crystalline forms are also discussed. Where affecting the dosage form, selection properties such as unpleasant taste or smell are mentioned. 

Baltrop D, Meek F. 1979. Effect of particle size on lead absorption from the gut. Arch Environ Health 34 280-285. 

Few clinical or epidemiological studies exist concerning inorganic tin intoxication primarily because inorganic tin(IV) compounds are poorly absorbed by mammals. The absorption from the gut for most compounds is less than 2%. However, when inorganic tin compounds are injected iv, they have a higher absorption and are usually stored in the bones with a half-life of approximately 400 days1. 

Crustaceans can accumulate zinc from both water and food (USEPA 1987). In uncontaminated waters, the diet is probably the major source of zinc. Absorption from the stomach is efficient and occurs, in part, via the hepatopancreas. When a large pulse of zinc reaches the blood from the stomach, some is excreted, but much is resorbed and stored in the hepatopancreas in a relatively nonlabile form. Ultimately, stored zinc is also excreted, although removal via the gut is unimportant (Bryan et al. 1986). Zinc absorption occurs initially at the gill surface, followed by transport on a saturable carrier in the cell wall, and is most efficient at low dissolved ambient zinc concentrations. Urinary excretion is an important body removal pathway, especially at high dissolved ambient concentrations when it can account for 70 to 80% of total zinc excretion (Bryan et al. 1986). 

Phosphate-binding agents decrease phosphorus absorption from the gut and are first-line agents for controlling both serum phosphorus and calcium concentrations (Table 76-3). 

Results of DEHP metabolism studies in vivo and in vitro, when considered together, suggest that the major route of metabolism for DEHP in fish consists of hydrolysis to the monoester. The monoester may then be conjugated with glucuronic acid, or further hydrolyzed to phthalic acid, or the remaining sidechain may be oxidized. This is similar to the reported pathway for DEHP metabolism in rats. In rats, dietary DEHP is to a large extent hydrolyzed to the monoester before absorption from the gut. When the monoester is administered orally, the urinary metabolites found are the same as those found after administration of DEHP (17). 

Legumes Cardiovascular disease Presence of saponin which decreases cholesterol absorption from the gut... 

This interpretation is borne out by another study [29] which, as its prime objective, compared the blood-level time relationships of prednisolone and its stearoylglycollate. The authors concluded that their results, showing consistently higher serum levels (the difference increasing progressively with time) after administration of the double ester, were only accounted for by reduction in the rate of inactivation of the ester compared with the parent steroid. The absence of any prolonged absorption from the gut was confirmed. Absorption was completed within two hours. 

Administration of 100 mg doxycycline, in the absence of foods, led to almost complete absorption from the gut and a peak blood level of 1-8 Mg/ml two hours after ingestion. Three times this dose was required.to produce a similar blood level in four hours in the case of 300 mg demethylchlortetracycline. The plasma half-life (after single dose) was 15 hours in the case of doxycycline and 12 hours for demethylchlortetracycline. This means that the half-life of doxycycline is seven hours longer than that of tetracycline. 

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