RU2362538C2 - Way of reception of ceramic biodegraded material on basis of renanite - Google Patents

Abstract

FIELD: medicine. ^ SUBSTANCE: way of reception of a ceramic biodegraded material on the basis of renanite, including charge preparation, containing sodium salt and calcium phosphate, formation, baking is described. As sodium salt the charge contains sodium chloride, and as calcium phosphate -calcium hydroxyapatite. The charge is prepared using interaction of aqueous solutions of calcium chloride and sodium hydrophosphate in alkaline medium. The structure of initial charge - 65-80% of calciun hydroxyapatite and 20-35% of sodium chloride is caused by adsorption of an accompanying product of reaction at synthesis of hydroxyapatite nanopowder. ^ EFFECT: uniform distribution of components provides formation of a ceramic biodegraded material on a basis of renanite in the range of temperatures 800-1200C within 2-6 hours. ^ 2 cl, 1 tbl, 1 ex

Description

The invention relates to medicine, namely to traumatology and orthopedics, maxillofacial surgery and surgical dentistry, and can be used to fill in bone defects, being a source of hydroxyapatite components (Ca ²⁺ , PO ₄ ^3- ) during in vivo biodegradation.

A known method of producing renanite NaCaPO ₄ as one of the phases during crystallization of glass in the system SiO ₂ -Al ₂ About ₃ -Na ₂ О-К ₂ О-Р ₂ О ₅ -F (1) or in SiO ₂ -CaO-Na ₂ OP ₂ O ₅ —FK ₂ O (2). The disadvantage of these methods is the fact that renanitis is not the only phase.

A known method of treating phosphate ores with sodium carbonate or potassium chloride at temperatures of 300-900 ° C, when the formation of renanite occurs only when phosphate stone interacts with sodium carbonate (3), or when treating a phosphate stone with aluminosilicate or sodium carbonate at 900 ° C ( four). This method is not suitable for the synthesis of renanite for medical use.

The synthesis of renanite powder is known by heating a mixture of Na ₂ CO ₃ and Ca ₂ P ₂ O ₇ at 1000 ° C for 10 hours (5). The solid-state synthesis of renanite thus performed, as is characteristic of any solid-state synthesis, gives a powder with low sintering activity and will require higher temperatures to form ceramics based on it.

The closest is the method (6) for producing material based on renanite NaCaPO ₄ from a mixture containing sodium salt (sodium bicarbonate NaHCO ₃ ) and calcium phosphate monetite CaHPO ₄ , including pressing the initial mixture and calcining at 1300 ° C for 16 hours. The disadvantage of this method is the high temperature and duration of the synthesis.

The task was to develop a method that would not contain these disadvantages. The problem was solved by the present invention.

In the method for producing a ceramic biodegradable material based on renanite, comprising preparing a mixture containing sodium salt and calcium phosphate, molding, calcining, according to the invention, the mixture contains sodium chloride as sodium salt and carbonate hydroxyapatite as calcium phosphate, wherein the mixture is prepared by the interaction of aqueous solutions of calcium chloride and sodium hydrogen phosphate in an alkaline environment.

The synthesis of the initial charge is carried out from aqueous solutions of calcium chloride with a concentration of 0.5-1.0 M and sodium hydrogen phosphate with a concentration of 0.3-0.6 M. After filtering the precipitate and drying, the powder is a mixture of sodium chloride and carbonate hydroxyapatite with a mass content of chloride sodium 20-35%. The formation of renanite occurs during firing of compression molded samples in the temperature range 800-1200 ° C for 2-6 hours.

When using more dilute solutions (less than 0.5 M for CaCl ₂ and 0.3 M for Na ₂ НРО ₄ ), the amount of sodium chloride adsorbed in the synthesis of carbonate hydroxyapatite is not enough to obtain a single-phase material. When using more concentrated solutions (more than 1.0 M for CaCl ₂ and 0.6 M for Na ₂ HPO ₄ ), an extremely thick suspension is formed during the synthesis, the mixing of which is difficult.

Firing the material at a temperature below 800 ° C with holding at this temperature for less than 2 hours does not provide single-phase material. Firing at temperatures above 1200 ° C with holding at this temperature for more than 6 hours leads to degradation of the microstructure of biodegradable ceramic material.

Example 1

1 liter of a 0.75 M solution of calcium chloride CaCl _{2 is} poured into 1 liter of a 0.45 M solution of Na ₂ HPO ₄ containing NaOH as a pH regulator taken in a 1.2-fold excess relative to that calculated according to reaction (1)

(6Na ₂ HPO ₄ +8 NaOH) +10 CaCl ₂ → Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ +20 NaCl + 6H ₂ O

The powder of the initial mixture after filtration and drying contains 27% NaCl and 73% carbonate hydroxyapatite Ca _{10-x / 2} (PO ₄ ) _6-x (CO ₃ ) _x (OH) ₂ . When heated for 4 hours at 1000 ° C, a ceramic biodegradable material based on renanite is formed in accordance with reactions that can be formally written as follows:

Ca _{10-x / 2} (PO ₄ ) _6-x (CO ₃ ) × (OH) ₂ → Ca ₃ (PO ₄ ) ₂ + CO ₂ ↑ + H ₂ O ↑ (T> 600 ° C)

Ca ₃ (PO ₄ ) ₂ + 2NaCl → 2NaCaPO ₄ + CaCl ₂ ↑ (T> 750 ° C)

Similarly, samples of a ceramic biodegradable material based on renanite were made under the stated conditions (table 1). From table 1 it follows that under the specified synthesis conditions of the initial mixture and the specified heat treatment conditions, a material is formed whose phase composition is represented by the renanite phase. Such a material is a biodegradable ceramic material and, therefore, a source of components for the formation of hydroxyapatite (Ca ²⁺ , PO ₄ ^3- ) in vivo.

Table 1. Synthesis Conditions The composition of the initial charge Heat treatment Phase Composition [Ca ²⁺ ] [PO ₄ ^3- ] Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ,% NaCl,% T, ° С t hour one 0.50 M 0.30 m 80 twenty 800 2 100% renanitis 2 0.75 M 0.45 M 73 27 1000 four 100% renanitis 3 1.00 M 0.60 M 65 35 1200 6 100% renanitis

Thus, experimental data show that the application of the claimed method allows to obtain material based on renanite from carbonate hydroxyapatite and sodium chloride, synthesized from aqueous solutions of calcium chloride and sodium hydrogen phosphate.

Literature

1. W. Holland, V. Rheinberger, S. Wegner, M. Frank Needle-like apatite-leucite glass-ceramic as a base material for the veneering of metal restorations in dentistry // J. of Materials science: materials in medicine 11 (2000) 11-17.

2. E. Apel, W. Holland, V. Rheinberger Bioactive rhenanite glass ceramic. US Patent US 7,074,730, Jul. 11, 2006.

3. H.K. Rautaray, R.N. Dash, S.K. Mohanty Phosphorus supplying power of some thermally promoted reaction products of phosphate rosks // Fertilizer Research 41 (1995) 67-75.

4. F.P. Glasser, R. P. Gunawardane Fertilizer material from apatite US Patent US 4,436,546, Mar. 13, 1984.

5. W. Suchanek, M. Yashima, M. Kakihana, M. Yoshimura β-Rhenanite (β-NaCaPO4) as weak interphase for hydroxyapatite ceramics // J. of European Ceramic Society 18 (1989) 1923-1929.

6. MMARamselaar, PJVan Mullem, W.Kalk, FCM Driessens, JR Dewijn, ALH Stols In vivo reactions to paniculate rhenanite and particulate hydroxyapatite after implantation in tooth sockets // J. of Materials science: materials in medicine 4 (1993) 311-317.

Claims (2)

1. A method of producing a ceramic biodegradable material based on renanite, comprising preparing a mixture containing sodium salt and calcium phosphate, molding, calcining, characterized in that the mixture contains sodium chloride as sodium salt and carbonate hydroxyapatite as calcium phosphate, wherein the mixture prepared by the interaction of aqueous solutions of calcium chloride and sodium hydrogen phosphate in an alkaline environment. 2. The method according to claim 1, characterized in that the use of aqueous solutions of calcium chloride with a concentration of 0.5-1.0 M, and aqueous solutions of sodium hydrogen phosphate with a concentration of 0.3-0.6 M, which provides the following content of components in initial charge, wt.%
sodium chloride 20-35 carbonate hydroxyapatite 65-80