Aluminium Hydroxide Gel Preparation

Dhristi JEE 2022-24

An introduction to Aluminum Hydroxide

Aluminium hydroxide is an inorganic compound made up of aluminium ion and hydroxide ions. It is an amphoteric compound which means it can act as an acid as well as a base. Aluminium hydroxide minerals occur in nature. It holds the property of an antacid. The IUPAC name of the aluminium hydroxide is Aluminium trioxide.


Hydrophobicity is a property of aluminium hydroxide. In most cases, it produces lyophobic solutions. The hydrolysis of aluminium chloride can be used to prepare aluminium hydroxide gels.


3H₂O + AlCl₃ Al(OH)₃ + 3HCl


Aluminium Compounds

Aluminium is an inorganic element belonging to the thirteenth group. Aluminium reacts with nitrogen gas and forms an aluminium nitride


Al + N₂ → AlN


Aluminium reacts with the oxygen gas and forms aluminium trioxide also known as alumina.


Al + O₂ → Al₂O₃


Aluminium reacts with hydrochloric acid and forms aluminium trichloride as a product and hydrogen gas as a byproduct. This aluminium trichloride is used in the preparation of aluminium hydroxide gels. 


Al + HCl → AlCl₃ + H₂


Aluminium reacts with the dilute sodium hydroxide solution and forms aluminium trihydroxide. This molecule is amphoteric in nature. Therefore, it further reacts with the dilute sodium hydroxide solution and forms sodium meta illuminate aa a product and hydrogen gas as a byproduct. 


Al + NaOH (dil) → Al(OH)₃ → Na[Al(OH)₄] + H₂


Aluminium hydroxide reacts with the water molecules and forms a solution. This reaction can be used to clear drains. This reaction is also used to remove the obstructions from the drainage pipe.


AlCl₃ + H₂O → [Al (H₂O)₆]⁺³ + 3Cl⁻


Aluminium trichloride reacts with hydrochloric acid and forms white fumes.


AlCl₃ + HCl → white fumes


Structure of Aluminium Hydroxide


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Aluminium cation is attracted with three hydroxide anions.


Properties of Aluminium Hydroxide

The Colour of aluminium hydroxide is white.


Its density is 2.43 g/cm³.


Its melting point is 300 degrees celsius.


Its molar mass is 78.0036.


Aluminium Hydroxide Gel Preparation

Aluminium hydroxide is hydrophobic in nature. Generally, it forms lyophobic solutions. Aluminium hydroxide gel preparation can be done with the hydrolysis of aluminium chloride.


AlCl₃ + 3H₂O → Al(OH)₃ + 3HCl


Step by Step Aluminium Hydroxide Gel Preparation

  1. Prepare the 2% aluminium chloride solution (by adding 2g of aluminium chloride in 100 ml water).

  2. Add 100 ml distilled water to the conical flask.

  3. Boil the water with the help of the wire gauze.

  4. Add 10 ml of the above prepared 2% aluminium chloride solution. Add this solution with the help of the dropper of the burette. As aluminium compounds are violent in nature.

  5. Constantly stir the solution while adding aluminium chloride.

  6. Heat the solution until you see a coloured solution. The colour of the aluminium hydroxide solution is white.

  7. Leave the mixture for cooling at normal temperature.

  8. The cooling solution is called aluminium hydroxide gel.

  9. Precaution You Need to keep During Aluminium Hydroxide Gel Preparation

  10. Clean the conical flask with a steaming process to avoid any kind of impurities.

  11. The byproduct (Hydrochloric Acid) formed in this reaction causes destabilization of the prepared gel. therefore, needs to be removed by the dialysis process.

  12. Aluminium chloride solutions need to be added in a dropwise manner.


Uses of Aluminium Hydroxide Gel

  • It is used for treating gastric ulcers.

  • It is used in making vaccines.

  • It is used in cosmetics.

  • It serves as an intermediate compound in various reactions.

  • It is used as a flame retardant.

  • It is used in the manufacturing of certain drugs.


Side Effects of Aluminium Hydroxide Gel

Aluminium hydroxide is generally used as a medicine. But to some people, it shows side effects when consumed. These side effects involve:


  • Constipation is a possibility. Other issues, such as haemorrhoids and intestinal blockage, could result as a result of this. Contact your doctor or pharmacist right away if constipation persists or worsens.

  • If your doctor has prescribed this drug, ensure that he or she has determined that the benefits are more and the side effects are negligible. The majority of people who use this medication experience no significant side effects.

  • Exercise daily and drink ample amounts of water to avoid constipation. Constipation can be avoided by taking this medicine with a magnesium-containing antacid. Stool softeners may be beneficial as well. Other antacids, stool softeners, and laxatives might be discussed with your doctor or pharmacist.

  • In the intestines, aluminium-containing antacids bind to phosphate, a vital physiological component. If your kidneys are normal, this can result in low phosphate levels, especially if you take big dosages for a long time.

  • Get medical help right away if you experience any of the following side effects or symptoms of a serious medical problem: black/tarry stools, mental/mood disorders (e.g., confusion, deep sleep), pain with urination, stomach/abdominal pain, or vomit that looks like coffee grounds. 

  • This medicine seldom causes a severe allergic reaction. However, if you witness any symptoms of some allergic response, such as a rash, redness, itching/swelling (particularly of the face/tongue/throat), extreme dizziness, or shortness of breath, go to the doctor right away.

  • This is a very important list of some potential adverse effects. Contact your doctor or pharmacist if you have any other side effects not listed above.


Aluminium Hydroxide: How to Use It

Before each dose, give the bottle a good shake. The flavour of the suspension may be improved by refrigerating it. Do not allow yourself to become frozen. This drug is most effective when taken without any other liquids. If necessary, dilute your dose with a little water.


This contains aluminium, which can interfere with the absorption of other medications (such as digoxin, iron, tetracycline antibiotics, pazopanib, and quinolone antibiotics like ciprofloxacin). To avoid this problem, talk to your doctor or pharmacist about how to schedule your medications.


If your acid problems persist or worsen after one week of use, or if you suspect you have a significant medical concern, seek medical help right away. 


Did You Know?

  • Aluminium hydroxide reacts with both acid and base.

  • Aluminium hydroxide is used in coating TiO2 nanoparticles.

  • Aluminium hydroxide is used to reduce phosphate levels in people with certain kidney conditions.

  • Aluminium hydroxide consumption reduces the absorption of the other medicines in the body. Therefore, two-hour gaps before and after taking aluminium hydroxide should be maintained for consuming other medicines with this.


Hence the article is very useful for the students to understand the properties, structure of aluminium hydroxide. Step by Step procedure of preparation of aluminium hydroxide gel is given in the above article.

FAQs on Aluminium Hydroxide Gel Preparation

1. What is the purpose of aluminium hydroxide gel?

The symptoms of excess formation of stomach acids, such as stomach distress, heartburn, and acid indigestion, are treated with this drug. Aluminium hydroxide is a fast-acting antacid that reduces stomach acid immediately.


Aluminium hydroxide is commonly taken before sleep or in between meals. Take a full glass (8 ounces) of aluminium hydroxide with a full glass of water. Before consuming a dose, shake the oral suspension well.

2. Is aluminium hydroxide beneficial to the stomach?

The symptoms of excess formation of stomach acids, such as stomach distress, heartburn, and acid indigestion, are treated with this drug. It's also used to minimise the symptoms of excess gas, such as belching, bloating, and stomach/gut pressure/discomfort.

3. What is the best way to store aluminium hydroxide?

Avoid freezing the liquid gel by keeping it at ambient temperature. The powder and compounded capsules should be kept in a tightly sealed container at room temperature, away from moisture.

4. What is aluminium hydroxide and why is it used in skincare?

Aluminium is in a stable state. In cosmetics, it acts as a skin protectant and an opacifying (decrease of a clear/transparent appearance). It can be found in a variety of cosmetics, including foundation, lipstick, and moisturiser.

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