Aluminium hydroxide interaction

A pyrotechnic mixture of aluminium powder with potassium perchlorate, barium nitrate, potassium nitrate and water exploded after 24 h storage under water. Tests revealed the exothermic interaction of finely divided aluminium with nitrate and water to produce ammonia and aluminium hydroxide. Under the conditions prevailing in the stored mixture, the reaction would be expected to accelerate, finally involving the perchlorate as oxidant and causing ignition of the mixture. 

The observation of a bonding arrangement of the type shown in Fig. 20a in (AlO)2-centred dimers is a recurrent feature of aluminium hydroxides and organooxides of simple, electron rich ligands [44, 99, 110, 125, 134, 204, 205, 214-231]. Those more complex dimers which have been noted take two main forms both polydentate terminal and bridging ligands allow multiple interactions with the Group 13 metal centres. 

The effect of mechanical activation on the synthesis of mullite 3Al203 2Si02 from the mixtures of activated aluminium hydroxide and silica gel was studied by Klevtsov, Mastikhin, Krivoruchko et al. [36], According to NMR, the interaction between the initial components is observed at the stage of mechanical activation, hi activated mixtures, a transition of AP from octahedron into tetrahedron and pentahedron-tetrahedron ones is observed. The formation of mullite occurs under heating of activated mixtures at 1100°C, while for unactivated mixtures at 1400°C only. Lower temperature allows to obtain the product in fine disperse state (S=50 m /g). 

Lithium aluminates. The compounds Li0H-2Al(0H)3-mH20 and LiCl-2Al(0H)3-mH20 (here m = 0.5 1.0 2.0) are easily synthesized under very low mechanical loading (blade mixer) in stoichiometric Al(0H)3+Li0H H20 and Al(0H)3+LiCl H20 mixtures [1,2]. It was stated that the dispersion of the initial aluminium hydroxide strongly influenced on the kinetics of mechanochemical interaction. The interaction rate increases linearly with the specific surface of the initial hydroxide. Fig. 6.1 shows the data on reactivity of initial hydroxide with different specific surface area (6 and 2 mVg, respectively). 

However, while oxidization may not change, interaction with the media may yield more soluble forms. A sparingly soluble metal compound can be considered as one for which a solubility product can be calculated, and which will yield a small amount of the available form by dissolution. However, it should be recognized that the final solution concentration may be influenced by a number of factors, including the solubility product of some metal compounds precipitated during the transformation/dissolution test, e.g. aluminium hydroxide. 

The absorption of some beta-adrenoceptor antagonists is altered by aluminium hydroxide, ampicillin, and food these are interactions of doubtful clinical relevance. 

Clinically important, potentially hazardous interactions with aluminium hydroxide gel, calcium containing preparations, iron preparations, magnesium preparations, NSAIDs... 

Information is very limited but it would appear that if rapid analgesia is needed with either mefenamic acid or tolfenamic acid, magnesium hydroxide can be given concurrently but aluminium hydroxide should be avoided. However, note that this applies to the fasted state, whereas NSAIDs are usually taken with or after food. Also note that magnesium hydroxide increased the endoscopically-detected gastric toxicity of ibuprofen in one study, see NSAIDs Ibuprofen and related drugs -i- Antacids , below. Aluminium hydroxide markedly reduces the speed of absorption. Sodium bicarbonate does not interact. Consider also NSAIDs Miscellaneous + Antacids , p.l42. 

Magnesium carbonate halves the maximum plasma levels of halofantrine, which may be clinically relevant. Aluminium hydroxide and magnesium trisilicate seem less likely to interact. 

Large rises in urinary pH due to the concurrent use of some antacids, diuretics or alkaline salts can cause quinidine retention, which could lead to quinidine toxicity, but there seems to be only one case on record of an adverse interaction (with an alumini-um/magnesium hydroxide antacid). Aluminium hydroxide alone appears not to interact. 

A study in 13 patients with tuberculosis, given a single 50-mg/kg dose of ethambutol, found that when they were also given three 1.5-g doses of aluminium hydroxide gel (at the same time and 15 and 30 minutes later) their peak serum ethamhutol levels were delayed and reduced. The average uri nary excretion of ethamhutol over a 10-hour period was reduced hy about 15%, but there were marked variations between individual patients. Some showed no interaction, and others showed increased absorption. No interaction was seen in 6 healthy subjects similarly treated. A further study in 14 healthy subjects found that 30 mL of an aluminium/magnesi-um hydroxide antacid decreased the AUC and maximum serum levels of a 25-mg/kg dose of ethambutol by 10% and 29%, respectively. ... 

Information on this interaction is limited, and it is not established. The clinical importance of the modest reductions in isoniazid levels with aluminium hydroxide in one study is uncertain, but likely to be small. However, aluminium/magnesium hydroxide did not interact, and neither did didanosine chewable tablets. 

Magnesium trisilicate reduces the absorption of nitrofurantoin, but the cUnical significance of this is unknown. Aluminium hydroxide is reported not to interact with nitrofurantoin. Whether other antacids interact adversely is uncertain. 

It is not yet known whether magnesium trisilicate significantly reduces the antibacterial effectiveness of nitrofurantoin but the response should be monitored. While it is known that the antibacterial action of nitrofurantoin is increased by drugs that acidify the urine (so that reduced actions would be expected if the urine were made more alkaline by antacids) this again does not seem to have been confirmed. The results of the in vitro studies suggest that the possible effects of the other antacids are quite small, and aluminium hydroxide is reported not to interact. 

It is believed that eertain of the quinolone functional groups (3-carboxyl and 4-oxo) form insoluble chelates with aluminium and magnesium ions within the gut, which reduces their absorption. " The stability of the chelate formed seems to be an important factor in determining the degree of interaction. It has been suggested from animal studies that adsorption of quinolones by aluminium hydroxide re-precipitated in the small intestine may be a factor in the reduced bioavailability of quinolones. See also Quinolones + Iron or Zinc compounds , p.336. 

Shiba K, Saito A, Shimada J, Hori S, Kaji M, Miyahara T, Kusajima H, Kaneko S, Saito S, Uchida H, Interactions of fleroxacin with dried aluminium hydroxide gel and probenecid. Rev InfectDis (1989) 11 (Suppl 5), S1097-S1098,... 

There is some evidence that the absorption of dicoumarol may be increased by magnesium hydroxide, but there is no direct evidence that this is clinically important. Aluminium hydroxide does not interact with either warfarin or dicoumarol, and magnesium hydroxide does not interact with warfarin. 

In 1982 a questioner in a letter asked whether haloperidol interaets with antaeids because he had a patient responding well to treatment with haloperidol who had begun to deteriorate when Amphojel (aluminium hydroxide) was added. In a written answer it was stated that there are no reports of this interaction but several clinicians had said that based on clinical impressions oral haloperidol and antacids should not be given together. 

Evidence of no interaction. A study in 4 patients chronically treated with digoxin 250 to 500 micrograms daily, found that the concurrent use of either 10 mL of aluminium hydroxide mixture BP or magnesium trisilicate mixture BP, three times daily, did not reduce the bioavailability of the digoxin and none of the patients showed any reduction in the control of their symptoms. ... 

Allgayer H, Rollinghoff W, Paumgartner G. Absence of in vivo and in vitro interactions of an aluminium hydroxide, magnesium hydroxide containii antacid with cimetidine in patients with peptic ulcer. Z Gastroenterol (1983) 21,351-4. 

Paroxetine appears not to interact to a clinically important extent with aluminium hydroxide or food, although absorption may be reduced by large quantities of milk. Concurrent use of paroxetine and aprepitant may slightly reduce the plasma levels of both drugs, but this is probably not clinically significant. 

Three haemodialysis patients had a marked reduction in the effects of allopurinol while taking aluminium hydroxide. Separating the doses by 3 hours reduced the effects of this interaction. 

---