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At least 19 recordsLinked to original sources

[Acetlysalicylic acid, protective antacid effect and lesions of the gastric mucosa. Effect of acetylsalicylic acid and an antacid drug (Gastropulgit Tabs) on the transmural electric potential in the human stomach].

Antacids are able to prevent acetylsalicylic acid-induced functional and morphological changes of the gastric mucosa. In order to test whether a new antacid in chewing-tablet form (Gastropulgit Tabs) might be able to protect the gastric mucosa from acetylsalicylic acid-induced functional changes similarly to liquid antacids the effect of this antacid on acetylsalicylic acid-induced changes of transmural gastric potential difference was measured in healthy volunteers. The decrease of transmural potential differences induced by 640 mg acetylsalicylic acid could be prevented by simultaneous addition of 2 tablets of Gastropulgit Tabs. Thus the antacid in tablet form is able-like liquid antacids-to protect the gastric mucosa against acetylsalicylic acid-induced functional changes.

Alum Compounds

[Peptone-stimulated gastric secretion and antacids. Effect of antacids with various content of calcium, magnesium and aluminiumions on the peptone-induced secretion of gastric juice, double-blind study].

A double-blind-trial was performed to prove the effect of antacids containing Mg (OH)2, Al (OH)3 and CaCO3 on peptone-stimulated gastric secretion (intragastric titration). A high efficacy of antacids given after meals was demonstrated. After application of antacids no significant rise in serum gastrin levels during intragastric titration was found. Serum calcium and magnesium levels remained unchanged. Peptone-stimulated gastric secretion was not influenced by application of different antacids within a period of 2 hours.

Aluminum

[Antacid therapy of upper abdominal symptoms. Double-blind study on the effect and tolerance of 2 antacids in gastritis , esophagitis and functional upper abdominal symptoms].

In a randomized, multicenter, double-blind study involving a total of 97 patients, the effectiveness and tolerance of Gelofalk, a new type of antacid combination comprising smectite--a natural alum earth, the specific molecular structure of which permits it to bind aggressive substances particularly well--aluminium hydroxide and magnesium hydroxide were investigated in comparison with a commercially available aluminium hydroxide antacid used by patients with gastritis, esophagitis and functional upper abdominal complaints over a treatment period of 4 weeks. The buffering capacity of a daily dose of Gelofalk was 135 mval, in the case of the reference antacid 210 mval. In terms of pain relief, reduction of accompanying symptoms, and endoscopic healing properties, Gelofalk proved very effective. Because of its particular properties, the preparation proved significantly superior to an aluminium hydroxide suspension in the case of most test parameters, in particular pain relief, onset of effect and heartburn. Gelofalk was very well tolerated; constipation or diarrhea occurred in only 2 cases each.

Abdominal Pain

An antacid tasting: the relative palatability of 19 liquid antacids.

The taste of liquid antacids is proposed as a major factor in patient compliance in taking such medication when prescribed. A study was made of the relative palatability of 19 antacids. The antacids can be divided into three groups of varying palatability (p less than 0.05).

Antacids

[Antacids and gastric mucosa. Protective effect of an antacid on acetylsalicylic acid induced functional lesions in the human gastric mucosa].

Salicylates do induce functional and morphological changes of the gastric mucosa: increased H+-back-diffusion, increased Na+-influx, and increased blood loss. Several functional parameters of the gastric mucosal barrier correlate with the transmural electrical potential difference (PD) which can be used as a sensitive, but unspecific parameter to detect functional changes of the gastric mucosal barrier. The effect of a salicylate alone and in presence of a liquid antiacid (Gastropulgit Gel) on transmural PD was measured in healthy volunteers. The presence of an antacid prevented the salicylate-induced drop of transmural PD. The tested antacid seems to exert a protective effect towards acute damage of the gastric mucosa induced by salicylates.

Antacids

Studies of neutralizing properties of antacid preparations. Part 7. 27Al NMR studies of aluminum species formed during acid dissolution of some antacid preparations.

Neutralization of some aluminum containing antacid preparations with hydrochloric acid were studied by 27Al NMR spectroscopy. It has been found that the nature and composition of aluminum species produced during the acid dissolution of preparations depends upon the substance used and on the pH at which the neutralization reaction proceeds. The results are consistent with the presence of both monomeric and polymeric species in solution containing aluminum in octahedral and tetrahedral environments.

Aluminum

[In vitro evaluation of antacid activity in gastric acid secretion in static and dynamic systems].

A valid in vitro evaluation of antacid capacity should consider: 1) the intragastric pH-range; 2) the antacid mechanism; 3) the dependence of antacid activity from intraluminal flux variations; 4) the interaction between proteins and antacids. Pharmacologically, a static method allows 1) to quantify H+ binding sites at different pH-end points of the titration: pH 3.0, 2.0 and 1.0 and 2) to characterize the antacid mechanism, neutralizing activity and/or buffering capacity. In dynamic conditions, using the "artificial stomach-duodenum" model the antacid-induced resistance to acidification was measured, the antacid mechanisms were characterized in regard to intraluminal gastroduodenal flux variations and the incidence of antacid activity on duodenal pH was evaluated. These procedures were applied to antacid evaluation of proteins, as natural antacids, and of drugs containing aluminium salts alone or combined with magnesium salts. Pharmacologically, antacid drugs exhibited a greater amount of H+ binding sites when titration end-point was pH 1.0 than pH 3.0 corresponding to the development of neutralizing activity and/or buffering capacity. In dynamic conditions, the drugs, like proteins, induced a potent resistance to acidification related to gastric emptying fluxes. Antacid effect was supported by neutralizing activity and/or by buffering capacity. It was prolonged by removal of H+ ions since lagtimes for recovering initial pH were longer than antacid total emptying, the dilution of intragastric content by H+ impoverished secretory flux contributing thus to prevent gastric acidification. At duodenal site, proteins and aluminium-containing antacids induced the same duodenal pH as controls, without antacids, while magnesium-containing antacids increased it.

Antacids

Effects of antacids on the clinical pharmacokinetics of drugs. An update.

Since a previous review by Hurwitz was published in 1977 a large number of reports on drug interactions with antacids have appeared, few of which are of clinical relevance. Tetracyclines form insoluble complex molecules by metal ion chelation with various antacids; tetracycline absorption may be decreased by more than 90% by this interaction. Of the new class of quinolone antibiotics, the absorption of ciprofloxacin and ofloxacin is reduced by 50 to 90% in the presence of aluminium- and magnesium hydroxide-containing antacids. In contrast to early work showing inhibition of the absorption of beta-adrenergic blocking drugs by antacids, subsequent studies did not confirm a reduction in the bioavailability of either atenolol or propranolol during antacid treatment; indeed, they showed an increase in the plasma concentrations of metoprolol when the drug was coadministered with an antacid. The bioavailability of captopril was significantly reduced in the presence of an antacid, and lower plasma concentrations of this angiotensin-converting enzyme inhibitor were accompanied by a reduction of its effect on the systolic blood pressure of the patients. The absorption of the cardiac glycosides digoxin and digitoxin is not inhibited by antacids to a significant degree, although earlier studies had shown a positive effect when the dissolution of the glycoside preparations was relatively poor. Antacids reduce the bioavailability of the H2-receptor antagonists cimetidine and ranitidine only when high antacid doses are used and when the drugs are administered simultaneously. The bioavailability of famotidine was not significantly altered by a potent antacid preparation, although a trend towards reduced absorption was observed. Iron absorption is significantly decreased in the presence of sodium bicarbonate and calcium carbonate, but is nearly complete when coadministered with aluminium-magnesium hydroxide. Nonsteroidal anti-inflammatory drugs such as naproxen, tenoxicam, ketoprofen, ibuprofen and piroxicam are not affected in their absorption by antacid treatment. Theophylline bioavailability is unchanged when the drug is given together with antacids, although its rate of absorption may be altered, leading to a reduction or an increase in the time of the occurrence of peak plasma drug concentrations.

Adrenergic beta-Antagonists

An artificial stomach-duodenum model for the in-vitro evaluation of antacids.

To improve the dynamic in-vitro evaluation of the effects of antacids, we have developed the 'artificial stomach' model by adding a 'duodenal reservoir' to receive the gastric emptying flux and simulated bicarbonate secretion, thus constituting an 'artificial stomach-duodenum' model. With this model we measured antacid-induced resistance to gastric acidification, and simultaneously evaluated the effect of antacid activity on the duodenal milieu. The model also permitted evaluation of the antacid effects of proteins (as natural antacids), and of drugs containing aluminium phosphate, alone or combined with magnesium oxide, or aluminium and magnesium hydroxides. At the gastric site, these drugs, as well as the proteins (that is, meat extract), induced a strong resistance to acidification due to the gastric emptying flux and to antacid composition. At the duodenal site, the decrease of the acid load penetrating into the duodenum varied, depending on the efficacy of gastric antacid activity. Duodenal pH was related to the equilibrium between bicarbonate secretion and the emptying of acid load. Proteins and aluminium phosphate induced the same duodenal pH as in the control tests without antacids, but magnesium-containing antacids increased it, thus decreasing bicarbonate consumption. The antacid mechanisms within the stomach, and the fate of antacids in the duodenal milieu, might explain the variation in duodenal pH in response to antacid administration.

Antacids

Gastric emptying of two radiolabelled antacids.

The rate of gastric emptying of two antacids, magaldrate and Maalox, was investigated using scintigraphy. Successful labelling of the antacids was carried out with 99mTc. The stability of the 99mTc-labelled antacids was satisfactory and there was no difference in antacid capacity between the labelled and unlabelled antacids. The studies were carried out on 15 healthy male volunteers. After an eight hour fast each subject ingested a standardised meal of 95.7 MJ (400 kcal). One hour later 10 ml of one of the two antacids previously labelled with 99mTc was administered. Serial detection by anterior and posterior projection of the amount of antacid retained in the stomach was performed to determine gastric emptying of antacid. One week later the study was repeated under the same conditions with the other antacid also labelled with 99mTc. The mean (SD) percentages of antacid retained in the stomach fit a linear model with a t1/2 of 86.6 (15.3) minutes for magaldrate and 52.3 (5.2) minutes for Maalox (p less than 0.01). When the mean percentages of retention at six time intervals were compared for both antacids, it was found that Maalox emptied much faster (p less than 0.01 at 15 and 30 minutes, p less than 0.02 at 45, 60, 75, and 90 minutes).

Adult

Evidence for the interaction between antacid and gastric mucosa using an "artificial stomach" model including gastric mucosa.

In light of evidence that certain aluminum-based antacids adhere to the gastric mucosa, we modified our previously described "artificial stomach" (AS) model by including a piece of hog stomach and compared the antacid activity of six aluminum-containing antacid products in the model with and without gastric mucosa. The activity of three of these, Maalox, Riopan and Supralox, was not significantly different in the two systems. In contrast, the activity of the other three, Aludrox, Phosphalugel and Simeco, was significantly greater with mucosa. Antacid activity of one product from each set (Supralox, Phosphalugel) was evaluated in two in vivo methods in human volunteers. For both antacids, results in vivo were similar to those obtained with the AS-containing mucosa. Without mucosa, in vivo and in vitro results were dissimilar for Phosphalugel, thus validating the modified AS. The difference between the two sets of antacids can be explained by 1) the fact that the Al:Mg ratio in the set affected by mucosa is greater than that of unaffected antacids, and 2) a weaker antacid load than in unaffected Supralox. We suggest that in an acid milieu, aluminum ions in antacids like Aludrox, Phosphalugel and Simeco are bound to sialic acid residues in mucus glycoproteins, thus retarding the transit of these antacids through both the AS and the real stomach and prolonging their activity in both situations. When the Al:Mg ratio is low or when the amount of antacid salts is large, aluminum ions tend to be buried in complexes, giving them less chance to interact with gastric mucus, so they transit the stomach more quickly.

Adult

Correlation of in vitro and in vivo methodology for evaluation of antacids.

The rate and extent of acid consumption of an antacid suspension and tablet were evaluated by in vitro and in vivo techniques. Four different test procedures were used to estimate in vitro antacid reactivity. In vivo effects were determined in the fasted and postcibal states in normal human subjects by a radiotelemetry procedure. The duration of elevation of intragastric pH greater than 3 was in agreement with in vitro estimates of total acid consumption of the antacid. There was also good correlation between onset, extent, and duration of in vivo antacid activity and a modified in vitro Beekman antacid test procedure. There was no significant difference in antacid activity of the tablet or suspension in either in vitro or in vivo test procedures. A wide variation in antacid activity was observed between subjects and also in the fasted versus postcibal states. These studies emphasize the requirements for standardization of antacid products by comparactive in vitro and in vivo evaluations to facilitate individualized dose titration of the antacid in each patient and correlation of the acid secretion rate in various types of GI disease with the antacid dose.

Aluminum Hydroxide