Effect of pH of precipitation on antacid properties of hydrous aluminum oxide
| Autor: | Ralph S. Levi, Surendra M. Bahal, Stanley L. Hem, Emanuel J. Russo |
|---|---|
| Rok vydání: | 1970 |
| Předmět: |
Chemical Phenomena
Bicarbonate Drug Compounding Inorganic chemistry Kinetics Pharmaceutical Science chemistry.chemical_element Chloride chemistry.chemical_compound Ammonia Chlorides Drug Stability X-Ray Diffraction Aluminium medicine Chemical Precipitation Sulfate Sodium bicarbonate Sulfates Oxides Hydrogen-Ion Concentration Bicarbonates Chemistry chemistry Antacids Sodium carbonate Gels medicine.drug Aluminum |
| Zdroj: | Journal of pharmaceutical sciences. 59(3) |
| ISSN: | 0022-3549 |
| Popis: | The effect of the pH of precipitation on the physical and chemical properties of hydrous aluminum oxide prepared by the reaction of aluminum chloride and strong ammonia solution NF; aluminum sulfate USP, and strong ammonia solution NF; and aluminum chloride, sodium bicarbonate USP, and sodium carbonate USP, was studied. During aging, changes may occur in the hydrous aluminum oxide structure which result in a loss in acid reactivity. This loss followed apparent first-order kinetics. The rate of loss was directly dependent on the pH of precipitation and continued until a constant end-point was reached. The percentage of theoretical reactivity remaining at the end-point was inversely related to the pH of precipitation. X-ray diffraction showed no differences in form, either initially or during aging. Gel stability appears to depend on the presence of anions in the gel structure. The concentration of these anions is related to the pH of precipitation. Data are presented which demonstrate that a stable, completely acid-reactive gel would be obtained if 1 mole of a monovalent anion such as chloride or bicarbonate or 0.5 mole of a bivalent anion such as sulfate is incorporated in the gel structure per mole of aluminum. |
| Databáze: | OpenAIRE |
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