Method of receiving powder of nano-crystalline calcium hydroxyapatite

FIELD: nanotechnology.

SUBSTANCE: invention relates to method of receiving of powder of nano-crystalline calcium hydroxyapatite. Nano-crystalline calcium hydroxyapatite is received by interaction of calcium hydroxide and solution, containing phosphate-ions, herewith suspension of calcium hydroxide is prepared directly before interaction with solution, containing phosphate-ions from solutions of calcium acetate and potassium hydroxide, herewith amount of calcium hydroxide is from 50 up to 100% in mixture of calcium-bearing components.

EFFECT: receiving of hydroxyapatite powder with particles size 30 - 50 nm.

3 dwg, 1 tbl, 1 ex

 

The invention relates to methods for producing powders of calcium hydroxyapatite (HAP), which can be used for the production of medical materials, stimulating regeneration of bone defects, sorbents and other

There are various ways to obtain a gap, in which the starting compounds using phosphoric acid or soluble phosphates of ammonium, potassium, sodium and soluble salts of calcium nitrate, chloride, acetate[1, 2, 3, 4]. The disadvantages of these methods is either high-temperature processing [1, 3], which leads to the coarsening of powders (larger particles); the application of freeze-drying, which requires complex hardware design [3], and low content of the synthesized product in suspension (1,2-3,2%), which leads to significant costs for filtering purposes. The disadvantage of this method [4] is the use of boiling in alkali, which results in coarse powder.

The known method [5] obtain a finely dispersed phase gap of poorly soluble calcium - dihydrophosphate calcium, pre-synthesized carbonate or calcium hydroxide and phosphoric acid. However, the confidence interval for the ratio of CA/P, specified in the method (1:0.4 to 0.7), will not ensure the preservation of stoichiometric HAP when viscotemp the temperature treatment, what is important when using this powder for ceramic materials.

The known method [6] obtain oxyapatite of poorly soluble calcium - brushite, which in accordance with the purpose of the invention receive a coarse powder by boiling in a 1.5 M solution of potassium hydrogen phosphate.

The number of known methods of obtaining gap of poorly soluble calcium - calcium hydroxide and phosphoric acid. The disadvantage of this method [7] is the complexity of the hardware design, which to conduct synthesis should provide multiple recirculation of the reaction mixture. The disadvantage of this method [8] is the need for pre-treatment of a suspension of calcium hydroxide ultrasound, which also requires the use of special devices. In method [9] indicated a molar ratio of calcium hydroxide to 1.33-2,50 will not ensure the preservation of the phase gap when using powder to obtain ceramics, which require high temperature processing.

Closest to the proposed invention is a method [10] to obtain a powder gap of suspensions of poorly soluble compounds of calcium is calcium hydroxide and the solution containing the phosphate ions (solution of ammonium hydrogen phosphate). The disadvantage of this method is to obtain coarse powder gap, kotorayauspev by carrying out synthesis using high temperature processing at high (950°C) temperature.

The aim of the present invention was to obtain nanocrystalline HAP powder.

This goal was achieved by the present invention.

In the method of producing powder of nanocrystalline HAP uses the interaction of a suspension of calcium hydroxide and a solution containing phosphate ions. According to the invention a suspension of calcium hydroxide is prepared immediately before engagement with a solution containing phosphate ions, merging solutions of acetate of calcium and potassium hydroxide, the quantity of calcium hydroxide ranges from 50 to 100% in a mixture of calcium-containing components.

A suspension of nanoparticles of calcium hydroxide is prepared by the interaction of calcium acetate and potassium hydroxide by the reaction (1) at room temperature for 0≤x≤5.

Formation of nanoparticles of calcium hydroxide largely ensured by the presence in suspension acetate ions, which are due to adsorption on the surface of the nanoparticles of the newly formed phase inhibit their growth by the mechanism of dissolution - crystallization. The reaction between the different values of x below (2-4).

At the lowest value of x=0 the entire calcium acetate interact with potassium hydroxide with education is the Finance of poorly soluble compounds calcium hydroxide. When x is greater than 5, the pH during the synthesis, the gap is reduced to values that do not provide preferred education gap may be formed of other phosphates of calcium.

the pH of the resulting suspension at 0≤x≤5 is 11-12 that provides for interaction with soluble phosphate-containing component To2NRA4preferred education gap. Gap of a mixture of hydroxide and calcium acetate was synthesized according to reaction (5):

To the resulting suspension of calcium hydroxide in a solution containing calcium ions and acetate ions added dropwise a solution of ammonium hydrogen phosphate with constant stirring at a temperature of 50-70°C. At temperatures below 50°C during the reaction is formed of amorphous calcium phosphate, which during high-temperature firing is converted into tricalcium phosphate that upon receipt of ceramics on the basis of the gap is undesirable. At temperatures above 70°C intensive allocation of acetic acid, and the size of the particles increases.

The processes occurring at values of x in the interval 0≤x≤5, is represented by reactions (6-8):

The resulting suspension gap is filtered, the filter cake is dried in a thin layer. According to roentgenova is the first analysis of the powder contains nanocrystalline HAP powder (Fig. 1-3). The particle size of the gap is 30-50 nm.

The invention is illustrated in the drawings and examples.

Fig. 1. Data of x-ray phase analysis for the powder synthesized from hydrogen phosphate and potassium suspension of calcium hydroxide in a solution containing acetate ions at x=5.

Fig. 2. Data of x-ray phase analysis for the powder synthesized from hydrogen phosphate and potassium suspension of calcium hydroxide in a solution containing acetate ions at x=2,5 (Example).

Fig. 3. Data of x-ray phase analysis for the powder synthesized from hydrogen phosphate and potassium suspension of calcium hydroxide in a solution containing acetate ions at x=0.

Example

The reaction of precipitation of calcium hydroxide is carried out, using 1 l of a 0.5 M solution of calcium acetate CA(CH3Soo)2and 0.75 M COHN, according to reaction (3)at room temperature.

To the resulting suspension was added dropwise to 1 l of 0.3 M solution of potassium hydrogen phosphate2NRA4at T=60°C. the Interaction takes place according to reaction (7):

The synthesized powder after separation of the precipitate, drying and disaggregation is a nanocrystalline HAP powder with the size of the individual crystallites of 30-50 nm.

Similarly, were synthesized powders of nanocrystalline HAP of a suspension of calcium hydroxide in a solution containing the eat acetate ions other stated values of x: x=5 and x=0 respectively, according to the reactions (6) and (8) (table). The content of the acetate ion in the initial suspension for all of the reported cases, is 1 M. From the table it follows that under these conditions, the size of the individual crystallites in the synthesized HAP powder is 30-50 nm.

Table
The value of XThe content of components in the suspension after synthesis of calcium hydroxideCA(Oh)2/(CA(Oh)2+Sa(CH3Soo)2)T, °CThe crystallite size
CA(Oh)2Sa(CH3Soo)2SPE3Soo
150.25 M0.25 M0.5 M50%7030-50 nm
22,50.375 M0.125 M0.75 M 75%6030-50 nm
300.5 M0 M1 M100%5030-50 nm

Data of x-ray phase analysis confirm the formation of nanocrystalline HAP with a particle size of 30-50 nm.

Thus, the experimental data show that the use of the claimed method allows to obtain nanocrystalline HAP powder with a particle size of 30-50 nm.

Literature

1. Vasilikou, Iperu, Vaikasi, Namechina, Maagazine, Vusikau. Patent RU 2038293, 26.06.1992. The method of obtaining hydroxyapatite.

2. Astaman, Oeacaie, Grabelnikova, Timetrack, Genealogia, Limasexadriana. Copyright certificate 710928, 25.01.1980. The method of obtaining calcium hydroxylapatite.

3. Vphantom, Uwimana, Pavlacka, Vagarosa. Patent RU 2050317, 20.12.1995. The method of obtaining powder of hydroxyapatite.

4. Ulitize, Sdhedule, Spiglazova and Aggripina. Inventor's certificate SU 1450852, 07.01.1987. A method of producing a sorbent - hydroxyapatite.

5. Nemanjina, Swipesy, Nassyrova, Aigialeia. Patent RU 2147290, 10.04.2000. A method of obtaining a finely dispersed phase of Hydra is xyapatite.

6. Him, Longoria, Approtec, Vpogosov, Bigelsen, Duende, Cigacice, All, Casamilano. Inventor's certificate SU 1503875, 30.08.1989. The method of producing oxyapatite.

7. Vframe, Evelio, Wenrui, Ayorou, Win, Vpev, Wielozadaniowy. Patent RU 2077475. 20.04.1997. The method of obtaining hydroxyapatite.

8. Egelstaff Patent RU 2149827, 27.05.2000. Method of production of fine hydroxyapatite high purity.

9. Spiacente, Nasriddinov. Patent 2104924, 20.02.1998. The method of obtaining hydroxyapatite.

10. Vpolicy, Havronicheva, Gaiola, Gesheva, Emoval and Namerow. Patent SU 1834836, 26.11.1991. The method of obtaining calcium hydroxylapatite.

The method of obtaining powder of nanocrystalline hydroxyapatite calcium interaction suspension of calcium hydroxide and a solution containing phosphate ions, characterized in that a suspension of calcium hydroxide is prepared immediately before engagement with a solution containing phosphate ions, merging solutions of acetate of calcium and potassium hydroxide, the quantity of calcium hydroxide ranges from 50 to 100% in a mixture of calcium-containing components.



 

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