RU2484850C1 - Calcium phosphate cement composite for bone defect filling - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine and concerns composites for plastic reconstruction of the injured bone tissues. The composite is presented in the form of reaction-set mixed powders: tricalcium phosphate, containing hydroxyapatite particles ranging in size from 38 to 220 mcm. Fluid cement is presented by a solution of magnesium, potassium and/or sodium phosphates, phosphoric acid and water. The components are taken in certain proportions. In the process of the material setting, a solid frame with a uniform distribution of ceramic particles contributing to an increase in strength is formed.

EFFECT: high mechanical properties and availability of raw materials allows using the given material widely for closing the bone cavities.

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Description

The invention relates to medicine, namely to plastic reconstruction of damaged bone tissue.

Calcium phosphate bone cements (CFCs) have been significantly developed over the past few years due to excellent biocompatibility and bioactivity, as well as ease of use in the form of injectable pastes that easily fill bone defects of almost any complex shape. Cement materials based on α-tricalcium phosphate (α-TCP) have bioactive and biocompatible properties.

In the work (Loreley Morejo n-Alonso, Oscar Jacinto Bareiro Ferreira, Raurl Garcia Carrodeguas, Luis Alberto dos Santos Bioactive composite bone cement based on a-tricalcium phosphate / tricalcium silicate J Biomed Mater Res Part In 2012: 100B: 94-102) cement the materials were obtained by mixing the reaction-hardening powder (RTP) of α-TCP with a cement liquid containing sodium phosphates. As a result, after setting, cement was obtained based on precipitated hydroxyapatite (OGA). The disadvantage of this cement is its low strength.

The closest in technical solution and the achieved effect are cement materials based on RTP α-TKF K. Takahashi, Y. Fujishiro, S. Yin, T. Sato PHA Preparation and compressive strength of a-tricalcium phosphate based cement dispersed with ceramic particles Ceramics International 30 (2004) 199-203 containing ceramic particles of zirconium, silicon or aluminum oxides. Cement was obtained by mixing α-TCP powder with water to a liquid suspension, followed by the addition of ceramic particles. After setting and hardening, a composite composition was formed: a matrix of hydroxyapatite or deficient hydroxyapatite and ceramic particles distributed in the matrix. The main disadvantage of these materials is their low strength. The disadvantages also include the presence of ceramic particles - zirconia, alumina or silicon oxide, the presence of which reduces the bioactivity of the composite material, because these phases are biologically alien (foreign) to the human body.

The technical result of the invention is to increase the strength of calcium phosphate cement material.

The technical result is achieved by the fact that a composite material based on calcium phosphate cement for filling bone defects based on a reaction-hardening powder containing α-tricalcium phosphate and a cement liquid containing water, according to the invention, the reaction-hardening powder additionally contains particles of hydroxyapatite ranging in size from 50 to 220 microns and the cement fluid additionally contains phosphoric acid, magnesium phosphate, sodium phosphate and / or potassium in the following ratio of components in calcium phosphate cement are:

in a reaction-hardening mixture of powders,% wt .:

Hydroxyapatite particles 38-220 microns in size - 5-50

Α-tricalcium phosphate powder - 50-95

in the following ratio of components in the cement fluid,% wt .:

Magnesium Phosphate - 30-60

Sodium and / or potassium phosphate - 3.5-25

Phosphoric acid - 0.5-3.0

Water is the rest

and the amount of cement fluid (ml) to the amount of reaction-hardening powder mixture (g) is in the range of 0.45-0.75.

Cement consisting of a reaction hardening powder (RTP): α-TCP and ceramic particles of hydroxyapatite HA and CZ based on phosphoric acid, magnesium, sodium and potassium phosphates is not known.

After mixing the CG and RTP, the reaction between the components begins, while the RTP partially dissolves with the formation of new phases - hydroxyapatite, precipitated hydroxyapatite and calcium deficient hydroxyapatite in various proportions. In the process of setting and hardening, a structure is formed consisting of crystals of newly formed phases covering the durable ceramic particles of hydroxyapatite, which helps to increase the strength of the cement material. The introduction of less than 5 wt.% Ceramic particles into RTP, as well as the use of a size of less than 38 microns, does not increase the strength. With the introduction of particles of ceramic hydroxyapatite more than 70 wt.%, As well as a size of more than 220 microns, the strength of cements begins to decrease sharply. In the case of using cement fluid in an amount less than the lower limit (CG (ml) / RTP (g) <0.45 ml / g), or the use of highly concentrated solutions of CG with a magnesium phosphate content of more than 60% wt., And the total content of potassium phosphate and sodium more than 25%, the resulting mixture has a high viscosity, which leads to the formation of numerous cracks during molding of the product of the desired configuration. When using CG in an amount above the upper limit (CG (ml) / CTP (g)> 0.75) and diluted CG with a high water content of more than 70% wt., Magnesium phosphate content of less than 30% wt. the mixture is too liquid, which does not allow to form the product due to the spreading of the mixture. In addition, setting time is significantly increased, which leads to a decrease in strength, especially in the first minutes of hardening. With the introduction of a total content of potassium phosphate and sodium of less than 3.5 wt.%, The porosity of the samples increases, which leads to a sharp drop in strength. When going beyond the content in the CG of phosphoric acid - 0.5-3.0 wt.%, The resulting cement material has a low strength.

Example 1. Obtaining sample No. 1. An RTP powder containing 0.5 g of HA ceramic particles with a size of 56-82 μm and a powder of 0.5 g of α-TCP is mixed with 0.25 ml of CG (50% wt, magnesium phosphate and 5% wt, potassium phosphate, 5% wt, sodium phosphate, phosphoric acid 1% wt., the rest is water). Mixing is carried out for 1-2 minutes with a metal spatula on the glass to a sour cream-like state, after which the mixture is placed in a cylindrical mold with a diameter of 8 mm After 15-20 minutes, the molded sample is taken out and placed in a thermostat at a temperature of 37 ° C in a solution of SBF (Simulated Body Fluid), corresponding to human blood plasma. After 24 hours, the cured sample has a compressive strength of 90 MPa.

Similarly, samples were made having compositions within the claimed, and their properties were determined in comparison with the prototype. The results obtained are summarized in table 1.

Table 1 Composition and properties of cement materials 3G, ml / RPS powder, g The size of the ceramic particles of hydroxyapatite The ratio of components in the RTP,% wt. Composition of cerebrospinal fluid,% wt. Setting time (37 ° С, 100% relative humidity), min Compressive strength, MPa ¹ GA α-TCP Magnesium Phosphate Sodium and / or Potassium Phosphate Phosphoric acid Water one 0.5 56-82 fifty fifty fifty 10 0.5 39.5 6-8 90 2 0.75 156-220 70 thirty 60 3,5 1,5 35 4-6 45 3 0.45 38-56 5 95 thirty 25 3 52 4-5 48 four 0.5 300 80 twenty - thirty - 70 35 5 9 (prototype) 0.3 - one hundred - - - one hundred 3 42 eleven 0.5 1-5 fifty fifty fifty 10 10 39 6-8- 42 12 0.85 56-82 10 90 10 40 0 fifty More than 20 5 13 0.15 - - one hundred 0 40 60 0 More than 60 Sample collapsed

Claims (1)

A composite material based on calcium phosphate cement for filling bone defects based on a reaction-hardening powder containing α-tricalcium phosphate and a cement liquid containing water, characterized in that the reaction-hardening powder additionally contains particles of hydroxyapatite ranging in size from 50 to 220 microns, and cement the liquid additionally contains phosphoric acid, magnesium phosphate, sodium phosphate and / or potassium in the following ratio of components in calcium phosphate cement:
in a reaction-hardening mixture of powders, wt.%:
Particles of hydroxyapatite with a size of 50-220 microns 5-50 Α-tricalcium phosphate powder 50-95
in the following ratio of components in the cement fluid, wt.%:
Magnesium Phosphate 30-60 Sodium and / or Potassium Phosphate 3,5-25 Phosphoric acid 0.5-3.0 Water Rest,
and the amount of cement fluid (ml) to the number of reaction-hardening powder mixture (g) is in the range of 0.45-0.75.