Aluminium Hydroxide

Aluminium hydroxide or aluminium hydroxycarbonate, is the most widely used antacid active. It is available as both a suspension and powder and maybe used alone or in combination with magnesium hydroxide. The widespread use of aluminium hydroxide gel in the formulation of antacids is based on its excellent pharmacological properties, which have been confirmed repeatedly over many years of administration. Aluminium hydroxide gel is an effective neutralizer and buffer of gastric hydrochloric acid, with no known harmful side effects. We offer a vast selection of aluminium hydroxide grades with a variety of properties.

Aluminium Hydroxide Powder

Aluminium hydroxide powders are manufactured from suspensions via defined drying processes which result in powders with varying density and particle size characteristics. The powders are primarily used in the production of antacid tablets, preferably after pre-granulation.

Alugel® A 211

Alugel® A 215

Alugel® A 225

Alugel® A 211 is the most widely used active for tablet, granulate or powder manufacture. Its high reaction capacity with hydrochloric acid ensures rapid onset and prolonged action in the stomach. The typical morphology of this spray dried gel can be seen in fig.1.

Alugel® A 215 has the fastest reaction rate of all aluminium hydroxide powders, requiring only a few minutes to achieve full reactivity (see fig. below). It is very stable on storage, with physical and chemical properties similar to those of Alugel® A 211.

Alugel® A 225 is an aluminium hydroxide powder with a low bulk density making it the active of choice when formulating with low density additives.
It is particularly suitable for use in candies and soft tablets due to its very fine particle size distribution. The small particles are easily mixed into the gum matrix of these types of products.

The fine particle size distribution of Alugel® A 225 also make it ideal for resuspending in liquid formulations.

Assay Al(OH)3 = min. 76,5%
Al2O3 = 47,0 - 60,0%
Assay Al(OH)3 = min. 76,5%
Al2O3 = 47,0 - 60,0%
Assay Al(OH)3 = min. 76,5%
Al2O3 = 47,0 - 60,0%
Density (tapped) 0,28 - 0,38 g/ml Density (tapped) 0,25 - 0,35 g/ml Density (tapped) 0,17 - 0,20 g/ml
d50 10 - 20 µm d50 10 - 20 µm d50 4 - 12 µm
Pharmacopoeia USP
Ph.Eur., BP
Pharmacopoeia USP
Ph.Eur., BP
Pharmacopoeia USP

Aluminium Hydroxide Wet Gel

Wet gels are used predominantly in the manufacture of liquid antacid preparations. Their ease of administration, pleasant taste, high active content and rapid onset of action compared to tablets, as well as the availability of practical packaging, e.g. dosed sachets, make liquid preparations a well accepted dosage form for antacids.

Alugel® suspensions are produced with a range of solid contents and rheological properties enabling the customer to choose the grade most suitable for their particular requirements.

Alugel® A 611

Alugel® A 621

Alugel® A 651

Alugel® A 611 is a standard, low viscosity, pumpable paste with an Al(OH)3 content of 14,5 – 16,8%. It is used primarily in formulations requiring good flow characteristics and a high active content. The low viscosity allows the incorporation of additional antacid components in powder form.

Alugel® A 621 is more reactive and has a higher viscosity than A611 making it suitable for formulations where no additional actives or viscosity regulators are foreseen. If required, additional substances may be incorporated after dilution. Alugel® A 621 provides remarkably stable suspensions with minimal sedimentation.

Alugel® A 651 is a highly concentrated gel with an Al(OH)3 content of 19,1 – 20,6%. It has a limited flow capability, but after dilution to approx. 15,3 % Al(OH)3, Alugel® A 651 becomes a free flowing suspension with minimum sedimentation characteristics and a rapid reaction rate with hydrochloric acid.

        Type LV
Assay Al(OH)3 = 14,5 - 16,8%
Al2O3 = 9,5 - 11,0%
Assay Al(OH)3 = min. 13,6%
Al2O3 = min. 8,9%
Assay Al(OH)3 = 19,1 - 20,6%
Al(OH)3 = 19,1 - 20,6%
Viscosity (Brookfield)

3000 - 7000 mPa s

(LV, 3/12)

Viscosity (Brookfield) 30 - 130 mPa s
(LV, 2/60) at 6,1% Al(OH)3
Viscosity (Brookfield) min. 6000 mPa s (LV 3/12)
min. 150 mPa s (LV 2/12) at 6,1% Al(OH)
Pharmacopoeia USP Pharmacopoeia USP Pharmacopoeia USP

Alugel® A 661

Alugel® A 671

Alugel® A 681

Alugel® A 661 is the most viscous of the Alugel® grades and has an
Al(OH)3 content of more than 13,6%. Alugel® A 661 is an outstanding product in terms of reaction velocity and storage stability. Even on dilution to 6,1% Al(OH)3 the suspension is extremely viscous and resistant to sedimentation, making it the product of choice for the formulation of stable suspensions without additional thickening agents.

Alugel® A 671 is a free flowing, pumpable, suspension with an
Al(OH)3 content of 19,1 – 20,6 %. It is suitable for use in double and triple strength antacid preparations which retain good flow capability. Alugel® A 671 displays only slight sedimentation even after extremely long periods in transit or storage. An extremely low sodium grade of Alugel® A 671 is available upon request. This special type enables the production of antacids which are classified as sodium-free according to FDA regulations.

With an Al(OH)3 content of 24,5 – 27,5 %, Alugel® A 681 is the most highly concentrated aluminium hydroxide suspension available today. Alugel® A 681 is a pumpable gel with an extremely low sodium content and a neutral taste, allowing the formulation of pleasant tasting products. As a result of its thixotropic properties, Alugel® A 681 displays no signs of sedimentation even after long periods in transit or storage.

Assay Al(OH)3 =min. 13,6%
Al2O3 = min. 8,9%
Assay Al(OH)3= 19,1 - 20,6%
Al2O3  = 12,5 - 13,5%
Assay Al(OH)3 = 24,5 - 27,5%
Al2O3 = 16,0 - 18,0%
Viscosity (Brookfield) 500 - 2500 mPa s (LV, 2/12)
at 6,1% Al(OH)3
Viscosity (Brookfield) max. 5000 mPa s (LV, 3/12) Viscosity (Brookfield) max. 5000 mPa s
(LV, 3/12)
Pharmacopoeia USP Pharmacopoeia USP Pharmacopoeia USP
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