CS235594B1 - A method of preparing a physiologically acceptable colloidal aluminum phosphate - Google Patents

Abstract

The invention relates to a method for preparing physiologically harmless colloidal aluminum phosphate. The essence of the invention consists in mixing a solution of aluminum sulfate with a concentration of 0.1 to 3 mol. l_1 and phosphoric acid with a concentration of 0.2 to 6 mol. l-1 in water with an aqueous solution of hydroxide or carbonate or bicarbonate of an alkali metal, preferably sodium, with a concentration of 0.1 to 15 mol. l-1, at a pH of 0.5 to 6.0 and a temperature of 5 to 100 °C, and the soluble salts are washed out of the precipitated product with water at a temperature of 5 to 100 °C. The invention can be used in the pharmaceutical industry.

Description

The invention relates to a process for the preparation of physiologically acceptable colloidal aluminum phosphate. The principle of the invention is to mix an aluminum sulfate solution with a concentration of 0.1 to 3 mol. 1 ¹ and the phosphoric acid) of concentration of 0.2 to 6 moles. 1 ^_1 in water with aqueous sodium hydroxide or carbonate or bicarbonate, preferably sodium, a concentration of 0.1 to 15 mol. I, ^-1, at pH 0.5 to 6.0 and a temperature of 5-100 ° C and the precipitated product is washed out with water-soluble salt thereof at 5 to 100 ° C.

The invention may be used in pharmaceutical formulations. industry.

The invention relates to a process for the preparation of a physiologically acceptable colloidal aluminum phosphate which reacts with hydrochloric acid to raise the pH.

For the preparation of antacid preparations, colloidal aluminum phosphate must be used as the base and must be present at 37 ° C in 0.1 mol / l hydrochloric acid. 1 ^_1 partly dissolved to form a buffer solution, which will increase the pH to 3 and further increases in pH does not occur. The colloidal aluminum phosphate for this use must switch on the condition that it contains only limited amounts of other ions such as alkali metal cations, chloride and sulphate anions. Colloidal aluminum phosphate as a suspension in water-colored carbon dioxide can only react neutrally or weakly acid.

Of the aluminum salts, aluminum chloride, aluminum hydroxide and aluminum sulfate are used to prepare the antacid colloidal aluminum phosphate. Colloidal aluminum phosphate is obtained from a solution of aluminum chloride and phosphoric acid by the addition of precipitating agents such as sodium hydroxide, a mixture of sodium carbonate and bicarbonate, or ammonium hydroxide at different pHs (Umbreit, H., Pol. J. Pharm. Pharmacol 30/116/1978). ). Colloidal aluminum phosphate is obtained from a solution of aluminum hydroxide and phosphoric acid by precipitation with magnesium oxide (Romanian Pat. No. 59247). Colloidal aluminum phosphate is obtained from an aluminum sulphate solution by precipitation with a solution of an alkali metal phosphate or dibasic phosphate (CSO A. O. No. 222898). Processes for the preparation of physiologically acceptable colloidal aluminum phosphate from aluminum chloride or aluminum hydroxide are economically disadvantageous. The process for preparing physiologically acceptable colloidal aluminum phosphate from aluminum sulfate is limited by the relatively low solubility of aluminum sulfate in water, which is disadvantageous in terms of utility.

In the process of physiologically acceptable colloidal aluminum phosphate, which is reacted with hydrochloric acid as the pH increases, the invention proceeds by mixing a solution of aluminum sulfate of a concentration of 0.1 to 3 M 1 ¹ and the phosphoric acid of a concentration of 0.2 to 6 mol. 1 ^_1 in water with aqueous sodium hydroxide, or carbonate, or bicarbonate, preferably sodium, a concentration of 0.1 to 15 mol. I ^-1 at pH 0.5 to 6.0 and a temperature of 5 to 100 ° C, and soluble salts are washed out of the heated product at 5 to 100 ° C.

An advantage of the process according to the invention is that a physiologically acceptable colloidal aluminum phosphate is obtained economically, which is used for the preparation of suspensions, pastes and, after drying, for the preparation of powders, granules and tablets.

Further details of the process for the preparation of the physiologically acceptable colloidal aluminum phosphate according to the invention are apparent from the examples.

EXAMPLE

0.87 kg of Alz (SO4) 3.18 H2O and 0.31 kg of 85% H3PO4 are dissolved in 2 l of water, filtered and, at 20 DEG C., a 1.12 kg filtered solution is added to this solution with stirring over 1 h. NazCOs. 10 HzO in 2 L of water. When the pH of the reaction mixture reaches 5.8, the precipitate is centrifuged and the soluble salts are washed off with water heated to 100 ° C.

Example 2

4.35 kg Al ₂ (SO 4) 3. 18 H 2 O and 1.55 kg of 85% HsPO 3 are dissolved in 10 L of water, filtered and a solution of 2 kg of NaOH in 10 L of water is added to this solution at 60 ° C with stirring over 2 h. When the pH of the reaction mixture reached 5.3, the precipitate was centrifuged and the soluble salts were washed out at 60 ° C with water.

Example 3

Dissolve 0,87 kg of Ah (SO4) 3.18 H2O and 0,31 kg of 85% H3PO4 in 5 l of water, filter and add a filtered solution of 0 to this solution at 15 ° C for 0,5 h. 33 kg NaHCO 3 in 5 L of water. When the pH of the reaction mixture reaches 5.5, the precipitate is filtered off and the salts are washed out with water at 20 ° C.

Claims (1)

Process for the preparation of physiologically acceptable colloidal aluminum phosphate, which reacts with hydrochloric acid to raise the pH, characterized in that an aluminum sulphate solution having a concentration of 0.1 to 3 mol is mixed. I ^'1 and of phosphoric acid of a concentration from 0.2 to 6 mol. 1 ^_1 in water YNALEZ with an aqueous solution of alkali metal hydroxide or carbonate or bicarbonate, preferably sodium, at a concentration of 0.1 to 15 mol. I, ^-1, at pH 0.5 to 6.0 and a temperature of 5-100 ° C and the precipitated product is washed out with water-soluble salt thereof at 5 to 100 ° C.