Hydrochloric acid, gastric

These drug are used for the medical treatment of agastric or duodenal ulcer, gastric hypersecretory (excessive gastric secretion of hydrochloric acid) conditions, and GERD. These drug may also be used as prophylaxis of stress-related ulcers and acute upper GI bleeding in critically ill patients. 

Gastric hydrolysis was estimated for monomethyltin EHMA, three salts of dibutyltin (maleate, dilaurate, and oxide), and monooctyltin EHMA in 0.07 mol/1 hydrochloric acid solution. Half-lives for hydrolysis were 0.27, 3.5, <0.5, <0.5, and 0.3 h, respectively. 

Hydrochloric acid and pepsin are the primary substances that cause gastric mucosal damage in PUD. Three different stimuli... 

An important gastric secretion is the hydrochloric acid that performs a number of functions in the stomach. This stomach acid is neutralized by pancreatic bicarbonate ion in the duodenum. Excess acid in the chyme stimulates chemoreceptors in the duodenum. This receptor stimulation elicits reflex inhibition of gastric motility. Excess acid also causes the release of secretin and gastric inhibitory peptide from the duodenum. These hormones contribute to inhibition of gastric contractions so that the neutralization process may be completed before additional acid arrives in chyme from the stomach. 

Rodriguez et al. [68] studied the stability of niclosamide in artificial gastric and intestinal juices. The gastric juice contained sodium chloride and hydrochloric acid with or without pepsin. The intestinal juice contained sodium phosphate with or without pancreatin. Niclosamide was incubated with the juices at 37°C for 6 h. The remaining intact drug and its degradation products (2-chloro-4-nitroaniline, 5-chlorosalicylic acid) were extracted with chloroform/methanol (5 1) and determined by TLC and HPLC. The drug was stable in these media for at least for 6 h. 

The two most important functional constituents of gastric juice, pepsin and hydrochloric acid, are known to vary substantially in concentration from individual to individual. 

The concentration of hydrochloric acid found in the gastric juice of an individual depends in part on the method of collection, but there is no doubt as to wide inter-individual differences. In a group of 96 "apparently normal men," Osterberg, et al.,51 found that achlorhydria was found in 5 per cent, 29 per cent, or 47 per cent... 

In a study from another source60 well individuals are classified as follows with respect to the concentration of hydrochloric acid in the gastric juice about 12 per cent, no acidity 15 per cent, hypoacidity 50 per cent, normal acidity and 23 per cent, hyperacidity. 

Although single samples from a particular individual may vary in acid content (as do the pepsin values), there is no question that well individuals (viz., those free from gastric disturbances) vary tremendously from individual to individual in their output of hydrochloric acid. The output decreases markedly with age, and the aging pattern differs from individual to individual. 

In the area of a gastric or duodenal peptic ulcer, the mucosa has been attacked by digestive juices to such an extent as to expose the subjacent connective tissue layer (submucosa). This self-digestion occurs when the equilibrium between the corrosive hydrochloric acid and acid-neutralizing mucus, which forms a protective cover on the mucosal surface, is shifted in favor of hydrochloric acid. Mucosal damage can be promoted by Helicobacter pylori bacteria that colonize the gastric mucus. 

Proteins are first denatured by the stomach s hydrochloric acid (see p. 270), making them more susceptible to attack by the endopeptidases (proteinases) present in gastric and pancreatic juice. The peptides released by endopeptidases are further degraded into amino acids by exopeptidases. Finally, the amino acids are resorbed by the intestinal mucosa in cotransport with Na"" ions (see p. 220). There are separate transport systems for each of the various groups of amino acids. 

Gastric juice is the product of several cell types. The parietal cells produce hydrochloric acid, chief cells release pepsinogen, and accessory cells form a mucin-containing mucus. 

The secretion of hydrochloric acid (H and Cl") by the parietal cells is an active process that uses up ATP and takes place against a concentration gradient (in the gastric lumen, with a pH of 1, the concentration is some 10 times higher than in the parietal cells, which have a pH of 7). 

The hydrochloric acid in gastric juice is important for digestion. It activates pepsinogen to form pepsin (see below) and creates an optimal pH level for it to take effect. It also denatures food proteins so that they are more easily attacked by proteinases, and it kills micro-organisms. 

Pharmacology Sucralfate does not affect gastric acid output or concentration. It rapidly reacts with hydrochloric acid in the stomach to form a condensed, viscous, adhesive, paste-like substance with the capacity to buffer acid and binds to the surface of gastric and duodenal ulcers. 

Secretion of hydrochloric acid (HCl) by the gastric mucosa in response to food intake makes the stomach very acidic. 

He proved that the acidity of the gastric juice is due to hydrochloric acid showed that the molecular weight of any substance is equal to twice its vapor density referred to hydrogen and put forth the hypothesis that the atomic weights of all of the elements, referred to hydrogen as unity, are integers. See ref. (54),... 

Chlorine in the Human Body. Chlorine enters into the composition of all secretions and excretions of the human body, and gastric digestion takes place in a medium containing hydrochloric acid (127). 

Pernicious anemia results from defective secretion of intrinsic factor by the gastric mucosal cells. Patients with pernicious anemia have gastric atrophy and fail to secrete intrinsic factor (as well as hydrochloric acid). The Schilling test shows diminished absorption of radioactively labeled vitamin B12, which is corrected when intrinsic factor is administered with radioactive B12, since the vitamin can then be normally absorbed. 

The digestion of proteins begins in the stomach, which secretes gastric juice—a unique solution containing hydrochloric acid and the proenzyme, pepsinogen ... 

The foregoing bases are usually employed as their salts with maleic, tartaric or hydrochloric acid. They usually depress the CNS, producing drowsiness and other side-effects that may preclude the use of a particular drug, but responses of different patients vary. Since antihistamine activity is shown by many compounds of varied structure it is suggested that they do not fit the histamine receptor completely as histamine does, but merely cover the anionic site, with their aryl residues adsorbed on some adjacent area. These compounds do not influence histamine-induced gastric secretion, and it was concluded that the latter effect is produced by a different type of histamine receptor, termed the H2 receptor. Most other effects of histamine are attributed to the Hi receptor. 

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