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At least 19 recordsLinked to original sources
PubMed1985

Interaction of type I collagen with sepiolite (magnesium silicate).

Type I collagen from calf skin interacts with magnesium silicate (sepiolite) resulting in a collagen-clay complex which is separated by centrifugation. The interaction primarily occurs with high molecular weight aggregates of the protein as indicated by the fact that collagen from the skin of lathyritic rats interacts to a lesser extent. Thus, when calf skin collagen is fully retained, 45% of protein from lathyritic animals remains in solution. Monomeric forms of collagen remain soluble after short periods of interaction with sepiolite; at 5 minutes, 34% of the calf skin collagen preparation is recovered in apparently monomeric form. In contrast protein-protein interaction produces the complete retention of the total collagen with longer periods of time.

Animals↗
PubMed1998

Magnesium silicate treatment of dietary heated fats: effects on rat liver enzyme activity.

In an effort to reduce the deleterious nutritional effects of oxidation products generated in heated fats, a partially hydrogenated soybean oil (PHSBO) used 7 d (7-DH) for frying foodstuffs was obtained from a commercial deep-fat frying operation. The used fat was treated with magnesium silicate (T-7DH). Isocaloric diets containing 15% of either 7-DH or T-7-DH fats were prepared and fed to male weanling rats for 10 wk in a pair-feeding experiment and compared to control rats fed nonheated PHSBO (NH). Animals fed the 7-DH diet showed higher liver enzyme cytochrome b5 and P450 activity than the T-7DH diet compared to the NH group, suggesting a positive effect of the treatment. These results suggested the presence of lower amounts of harmful compounds in the diet containing the heated used oil which had been treated with the active adsorbent.

Animals↗
PubMed1977

Use of magnesium silicate before gas-liquid chromatography for determination of "total estrogens" in urine during pregnancy.

The authors propose a simple, rapid, reproducible and reliable method for determination of "total estrogens" in urine during the last three months of pregnancy. The procedure consists of separation of free urinary estrogens, obtained after rapid hydrolysis, on a column of magnesium silicate. The estrogens are adsorbed on the column at acid pH and eluted by 1 M potassium hydroxide. Following extraction of the eluate by diethyl ether and formation of trimethylsilyl ether derivatives, the steroids are analysed by gas-liquid chromatography. This new procedure is used routinely in our laboratory, one assay being carried out in less than three hours. The results appear to be comparable to those obtained with classic methods. We wish to report the elimaination curves of "total estrogens" during normal pregnancies and their allowable limits.

Chromatography, Gas↗
PubMed1995

Pharmacokinetic study of zeolite A, sodium aluminosilicate, magnesium silicate, and aluminum hydroxide in dogs.

Zeolite A is a synthetic zeolite which may have therapeutic utility in osteoporotic individuals because of its ability to stimulate bone formation. A study of Zeolite A (30 mg/kg), sodium aluminosilicate (16 mg/kg), magnesium trisilicate (20 mg/kg), and aluminum hydroxide (675 mg) was designed in beagle dogs. The purpose of this study was to compare the oral bioavailability of silicon and aluminum from Zeolite A, sodium aluminosilicate, magnesium trisilicate, and aluminum hydroxide in dogs. Twelve female dogs received each compound as a single dose separated by one week in a randomized, 4-way, crossover design. Plasma samples were drawn at time 0 and for 24 hours after dosing. The concentrations of silicon and aluminum were determined by graphite furnace atomic absorption. The mean plasma silicon AUC values (+/- S.D.) were 9.5 +/- 4.5, 7.7 +/- 1.6, 8.8 +/- 3.0, 6.1 +/- 1.9 mg.hr/L and the mean plasma silicon Cmax values (+/- S.D.) were 1.07 +/- 1.06, 0.67 +/- 0.27, 0.75 +/- 0.31, 0.44 +/- 0.17 mg/L for Zeolite A, sodium aluminosilicate, magnesium trisilicate, and aluminum hydroxide respectively. Although mean silicon AUC and Cmax values were elevated when compared to baseline after administration of the silicon containing compounds, only the AUC from Zeolite A reached statistical significance (p = 0.041). The mean plasma silicon Tmax values (+/- S.D.) were 7.9 +/- 6.4, 5.8 +/- 4.6, 6.9 +/- 6.3 and 8.5 +/- 3.4 hrs for Zeolite A, sodium aluminosilicate, magnesium trisilicate and aluminum Hydroxide respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗
PubMed1993

[Hygienic regulation of dust of magnesium-silicate minerals and fireproof materials].

Chronic experiments on rats showed that the dust of silicomagnesian refractory and dunite (a raw material for refractory production) extracted in Kytlym differ insignificantly in fibrogenic activity, but rank below the quartzite extracted in Pervouralsk (MAC-1 mg/cu m). The short study analyzing the cytologic changes of bronchoalveolar lavage determined the cytotoxicity of silicomagnesian refractory and 4 other types of dunite. The estimated cytotoxicity also ranked below that of quartzite from Pervouralsk. The MAC equal to 4 mg/cu m was suggested for the group of aerosols produced by dunite and silicomagnesian refractories. These aerosols are assigned to the 3rd jeopardy class and possess basically fibrogenic activity.

Animals↗
PubMed1992

Interaction between polyethylene films and bromhexine HCl in solid dosage form. IV. Prevention of the sorption by addition of magnesium aluminum silicate.

The effects of magnesium aluminum silicate (MAS) addition on the sorption of bromhexine HCl to polyethylene film in tablets were studied. The addition of MAS prevented the sorption of bromhexine HCl to polyethylene film. In order to investigate the mechanism, the interaction between bromhexine HCl and MAS was studied by the powder X-ray diffraction method. It was observed that bromhexine HCl was preferentially adsorbed to the surface of MAS rather than to polyethylene film. The adsorption was accelerated at high temperature and reduced pressure conditions. The sorption of bromhexine base and bromhexine HCl to packaging material were compared using tablet dosage forms. The sorption of bromhexine base to polyethylene film was greater than that of bromhexine HCl.

Aluminum Compounds↗
PubMed1993

Role of microenvironmental deterioration of the bone marrow in the development of bone atrophy in magnesium silicate-treated rats.

The role of microenvironmental deterioration of the bone marrow in the development of bone atrophy was examined in rats with bone atrophy induced by magnesium silicate. In the tibial metaphyses, proliferation of myelocytic elements of haematopoietic tissue was prominent and caused narrowing of sinusoids, increased distance between sinusoids and trabecular bone and atrophy of trabecular bone. There was a significant correlation in volume percentage between haematopoietic cells and trabecular bone, between haematopoietic cells and sinusoids and between sinusoids and trabecular bone. These results imply that atrophy of trabecular bone is related to microenvironmental deterioration of the bone marrow, that is, a decrease in efficiency of exchange of nutrients and waste products between sinusoids and trabecular bone due to the proliferation of haematopoietic cells and a deficiency of nutrient supply to the bone marrow due to the narrowing of sinusoids.

Animals↗
PubMed1991

Insulin secretion in magnesium silicate-induced osteopenia in rats.

Local inflammation induced in rats by subcutaneous injection of magnesium silicate is followed by general metabolic, endocrine and immune reactions. Three weeks after inflammation induction, important bone loss, inflammation-mediated osteopenia (IMO) were found. The study proposes to investigate if IMO influences endogenous insulin secretion and if insulin therapy modifies the amount of bone loss, knowing its osteoprotective effect. Experiments were carried out on adult rats, three weeks after local inflammation induction. Baseline glucose and insulin levels did not change as compared to controls. After glucose stimulation, insulinogenic index decreased in the IMO group, which evidences decrease of insulin secretion. Insulin treatment initiated at the same time with IMO did not induce significant changes as regards the response to glucose tolerance test. However, bone calcium was increased as compared to the untreated IMO group, without reaching the control level.

Animals↗
PubMed1982

Disposition, intestinal absorption and drug metabolizing enzyme activities after multiple doses of indomethacin in rat and effect of antacid and dicyclomine on the parameters.

The effect of repeated treatment with indomethacin (IND) on the disposition and intestinal absorption of the drug and microsomal drug-metabolizing enzyme activities were studied in comparison with coadministration of the drug and magnesium silicate or dicyclomine in male Wistar rats. The plasma decay curve of IND following a rapid i.v. injection (6 mg/kg) was found to be biexponential. The elimination rate constant (beta) of beta phase was 0.138 +/- 0.015 h-1. The beta after the multiple dosing of IND (6 mg/kg/d for 7 d, p.o.) was significantly decreased as compared with that after a single dosing. In the multiple dose group coadministered magnesium silicate (0.6 g/kg), the AUC0 leads to infinity was 2 times that after the multiple dosing of IND alone. The repeated administration (8 times every 16 h) with IND (4 mg/kg) alone and IND plus the antacid respectively gave the results similar to those in the multiple dosing. In the multiple treated group with IND alone, the drug-metabolizing enzyme activities were significantly decreased (32-43%) as compared with the control, however, the coadministration of magnesium silicate partly protected the decrease. The intestinal absorption rate constant of IND determined by in situ method was decreased after the multiple dosing of IND alone, but the constant was recovered to the control value after coadministration of the antacid. Following the multiple dosing of IND alone, the centrilobular necrosis in liver and a partial omission of the villi of intestinal epithelium were observed, but the concurrent dosing of magnesium silicate did not produce histopathological changes.

Animals↗
PubMed1997

Reduced tetracycline bioavailability caused by magnesium aluminum silicate in liquid formulations of bismuth subsalicylate.

RATIONALE: Bismuth subsalicylate, tetracycline hydrochloride, and metronidazole are widely used in combination for the treatment of Helicobacter pylori infections. As a result, there is renewed interest in the interaction between tetracycline and bismuth subsalicylate. OBJECTIVE: To determine whether the observed decrease in tetracycline bioavailability is due to the active drug bismuth subsalicylate via complexation, or to magnesium aluminum silicate (Veegum), an inactive excipient present only in the liquid formulation of bismuth subsalicylate, which might adsorb the tetracycline, rendering it unavailable for systemic absorption. METHODS: Eleven healthy volunteers participated in a randomized three-period, three-treatment complete crossover study with a 7-day washout interval between treatments. After an overnight fast, subjects received a 500-mg capsule of tetracycline hydrochloride with either tap water, 30 mL of bismuth subsalicylate (525 mg) liquid containing Veegum (Pepto-Bismol), or 30 mL of a specially formulated bismuth subsalicylate (525 mg) liquid without Veegum. Blood was collected for 24 hours after each dose of tetracycline. Serum was assayed for tetracycline concentration by HPLC. In addition, standard in vitro ultraviolet spectrophotometric methods were used to determine the capacity for complexation of bismuth with tetracycline and for adsorption of tetracycline to Veegum. RESULTS: Compared with the reference treatment of tetracycline hydrochloride with water, the liquid formulation of bismuth subsalicylate containing Veegum decreased the maximum serum concentration (Cmax) of tetracycline by 21% and the serum tetracycline AUC by 27% (p < 0.001). The bismuth subsalicylate formulation without Veegum resulted in decreases in Cmax and AUC of 11% and 13%, respectively (p > 0.05 vs. tetracycline hydrochloride with water). Multiple linear regression analysis of the spectral absorbance data demonstrated a calculated recovery of tetracycline of 100.9% and, therefore, a lack of in vitro complexation with bismuth. At pH 1.2, the amount of tetracycline adsorbed to Veegum ranged from 91.5% to 97.2% over the concentration range of 0.25 to 2 mg/mL. At pH 7.0, the values ranged from 82.9% to 83.9% over the concentration range of 0.25 to 1 mg/mL. CONCLUSIONS: In vitro and in vivo data from this study indicate that Veegum, a suspending agent, and not the active agent bismuth subsalicylate, is the primary ingredient in liquid formulations of bismuth subsalicylate responsible for a decrease in tetracycline bioavailability. In addition, the mechanism of interaction is not likely due to complexation between tetracycline and bismuth subsalicylate, as previously postulated, but rather is caused by adsorption of tetracycline to the excipient Veegum, which is present only in the liquid formulation of bismuth subsalicylate. The clinical relevance of this interaction has not been determined.

Adolescent↗
PubMed1992

An aluminum silicate binding assay for quantitation of degradation of cholecystokinin octapeptide and other short peptides.

Most available techniques for the quantitation of enzymatic degradation of peptide hormones are time-consuming and require expensive equipment and/or novel reagents. Our aim here was to develop a rapid and sensitive assay for the measurement of degradation of cholecystokinin octapeptide (CCK-8) as well as other short, hydrophobic peptides. The proposed technique is based on our novel observation that intact CCK-8, but not its degradation product(s), binds to Lloyd reagent, a form of aluminum silicate. When radiolabeled CCK-8 was exposed to rat liver cytosol containing endogenous CCK-degrading activity, there was a time-dependent decrease in the binding of radiolabel to aluminum silicate [from 86 to 8% over 60 min at 37 degrees C]. The decrease in binding closely paralleled the extent of CCK-8 degradation over time as assessed by high-performance liquid chromatography and immunoprecipitation with specific polyclonal antibodies to CCK-8. While aluminum silicate did not efficiently bind to C-terminal and N-terminal CCK tetrapeptides, magnesium silicate bound to both tetrapeptides (> 82%), but not to their radiolabeled degradation products. Both aluminum and magnesium silicate also extensively bound (> 82%) to other peptide hormones including Met-enkephalin, somatostatin, and secretin, but did not bind their degradation products. These binding assays will be useful in studies of peptidases which degrade cholecystokinin or other small, hydrophobic peptides.

Aluminum Silicates↗