Aluminium hydroxide

About: Aluminium hydroxide is a research topic. Over the lifetime, 2043 publications have been published within this topic receiving 22032 citations. The topic is also known as: Al(OH)3 & Amphojel.

Enhancement of drug absorption by antacids. An unrecognised drug interaction.

Abstract: Antacids are widely used for many disorders. The potential of antacids to interact with other concomitantly ingested drugs is well recognised. These interactions usually result in reduced or delayed absorption of the affected drug. However, this is not always the case. In contrast to aluminium hydroxide, magnesium hydroxide and sodium bicarbonate can enhance the absorption of some drugs. For example, magnesium hydroxide can increase the rate and sometimes even the extent of absorption of certain nonsteroidal anti-inflammatory drugs (e.g. tolfenamic acid, mefenamic acid and ibuprofen), sulphonylurea antidiabetic agents [e.g. glipizide, glibenclamide (glyburide) and tolbutamide] and the oral anticoagulant dicoumarol (bishydroxycoumarin). These weakly acidic drugs are nonionised at gastric pH, but are sparingly water soluble. Elevation of the gastric pH by administration of magnesium hydroxide or sodium bicarbonate increases the solubility and absorption of such sparingly water soluble agents. Chelate formation may be involved in the increased absorption of dicoumarol by magnesium hydroxide. In combination antacids containing both aluminium hydroxide and magnesium hydroxide, the absorption enhancing effect of magnesium hydroxide seems to be counterbalanced by the opposing effects of aluminium hydroxide. The clinical significance of increased drug absorption is not clear. However, accelerated and enhanced absorption of analgesic drugs may be beneficial when rapid pain relief is desired. In contrast, an unexpectedly increased hypoglycaemic or anticoagulant effect may be potentially dangerous. Therefore, a knowledge of the potential effect of antacids on the absorption of other drugs is clinically important.

A systematic investigation of aluminium ion speciation at high temperature. Part. 1. Solution studies

Abstract: Speciation diagrams of aluminium ions in aqueous solution (0.2 M) at high temperature (90 °C) have been obtained from 48 h time-resolved multi-batch titration experiments monitored by 27Al NMR spectroscopy, potentiometry and dynamic light scattering. The quantitative speciation patterns and kinetic data obtained offer a dynamic picture of the distribution of soluble and insoluble Al species as a function of hydrolysis ratio h (h = [OH−]/[Al3+]) over a very broad range of conditions (−1.0 ≤ h ≤ 4.0). Monomeric, small oligomeric, tridecameric (the ‘Al13-mer’) and the recently characterised 30-meric aluminium species (the ‘Al30-mer’) as well as aluminium hydroxide have been identified and quantified. The Al13-mer species dominates over a relatively broad range of hydrolysis ratios (1.5 ≤ h ≤ 2.7) during the first 6 h of experiment, but are gradually replaced by Al30-mers at longer reaction times. Kinetic profiles indicate that the formation of the Al30-mer is limited by the disappearance of the Al13 species at mildly acidic conditions. The estimated rate constants of both hydrolytic processes show good internal correlation at h ≥ 1.5. The effect of local perturbations leading to the formation of aluminium hydroxide below the electroneutrality point (h = 3.0) has been estimated quantitatively.