RU2357766C2 - Method of sterilisation and pre-implantation storage of biological prostheses for cardiovascular surgery - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention concerns medicine, particularly cardiovascular surgery, and can be applied in sterilisation and storage of bioprostheses. Method of sterilisation and pre-implantation storage of biological prostheses for cardiovascular surgery involves flushing of preliminarily preserved biological prosthesis in sterile 0.9% sodium chloride solution and prosthesis placement in sterilisation agent on phosphate buffer. 2-bromine-2-nitropropane-1.3-diol bactericide medication obtained with 0.05-0.2 M phosphate buffer at pH 4.0-8.0 in 0.01-2.0% concentration at 5-40°C is used as sterilisation agent.

EFFECT: high antibacterial activity, preserved resilience of biomaterial and structure of biological tissue, significant reduction of bioprosthesis flushing time before implantation.

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Description

The invention relates to medicine, namely to preimplantation processing of biological prostheses for cardiovascular surgery, and can be used for storing biological prostheses of heart valves, blood vessels, etc. until implantation.

A known method for storing biological prostheses in a solution containing methyl and propyl parabens (US Patent 5188834, class A61L 27/36, published 02.23.1993). The disadvantage of this method is that parabens have only a bacteriostatic effect and are partially deactivated in the presence of proteins, which increases the likelihood of loss of sterility during prolonged storage of biological prostheses.

A known method of sterilization and storage of xenoprostheses in a 0.5% solution of glutaraldehyde (Guidelines for sterilization of xenobioprostheses with a solution of glutaraldehyde. USSR Ministry of Health. N 28-6 / 26 from 09/19/1986). The disadvantage of this method is the long washing of the bioprosthesis from the sterilizing solution - for 90 minutes with vigorous stirring in 500 ml of a 0.9% sterile sodium chloride solution with a change of solution every 15 minutes.

A known method of preservation and sterilization of biological prostheses of heart valves and blood vessels in a buffer solution of diglycidyl ether of ethylene glycol (DEE) (RF patent No. 20088767, class A01N 1/00, published in 1994, bull. No. 5). Preservation and sterilization of biological material is achieved by treating with a 2-5% DEE solution. Until the implantation of the product is stored in the same solution.

Preimplantation treatment involves washing bioprostheses from a preservative in 500 ml of a sterile 0.9% sodium chloride solution for 1 hour with a three-time change of solution. This washing mode allows you to completely get rid of an unbound preservative and eliminate the systemic and local toxic effects of the implantable product on the patient's body. The disadvantage of this method is the duration of the washing regime, which leads to an increase in operation time.

The technical result of the invention is to enhance the sterilizing effect during storage and to reduce the time for washing bioprostheses from a preservative solution before implantation, by using a new bactericidal preparation prepared in 0.05-0.2 M phosphate buffer.

A method for sterilization and preimplantation storage of biological prostheses is proposed, including washing a previously preserved biological prosthesis in a solution of a sterile 0.9% sodium chloride solution and placing it in a sterilizing agent on phosphate buffer.

The difference is that the bactericidal preparation 2-bromo-2-nitropropane-1.3-diol is used as a sterilizing agent, prepared on 0.05-2.0 M phosphate buffer at a pH of 4.0-8.0 at a concentration of 0.01 -2.0% and a temperature of 5-40 ° C.

This drug is known in the reference literature under the name Bronopol, BioBan, Protectol BN, etc.

The proposed method allows to obtain a solution for sterilization and storage of biological prostheses, which has high antibacterial activity, does not adversely affect the structure and properties of pre-preserved biomaterial.

Used sterilizing agent refers to chemically synthesized substances and is an effective bactericidal agent against gram-positive and gram-negative bacteria, is also active against various fungal flora (US Patent No. 4859705, CL A01N 33/18, A01N 41/02, published 08/22/1989). In the cosmetology industry, 2-bromo-2-nitropropane-1.3-diol is widely used as a preservative, it is a water-soluble preparation, the solution is stable during long-term storage (see table 1).

Table 1. The decomposition period of 2-bromo-2-nitropropane-1.3-diol Solution temperature The decomposition period in aqueous solutions pH 4.0 pH 6.0 pH 8.0 5 ° C > 5 years > 5 years 6 months 25 ° C > 5 years > 5 years 4 month 40 ° C 2 years 4 months 8 days

Thus, the greatest antibacterial activity of 2-bromo-2-nitropropan-1.3-diol is manifested at a pH of 4.0-6.0 and a temperature of not more than 40 ° C.

The preliminary stage of preservation of biological prostheses can be carried out by any preservative.

The following is an example implementation of the proposed method.

Example 1. Prepared by existing selection methods, the native tissue is washed with 0.9% sodium chloride solution, then placed in a 2-5% DEE solution (patent No. 2008767). After 21 days of preservation, the biological prosthesis is washed in a 0.9% sodium chloride solution for 1 hour with a three-time change of solution and transferred to storage in a 0.01-2.0% solution of 2-bromo-2-nitropropane-1.3-diol.

It is proposed to use a solution of 2-bromo-2-nitropropane-1.3-diol with a pH of 4.0-8.0 and at a temperature of 5-40 ° C for sterilization and storage of biological prostheses. The drug is diluted in 0.05-0.2 M phosphate buffer.

To assess the sterilizing effect, bacteriological tests were performed - biomaterial samples contaminated with St.aureus, E. coli, Ent.faecalis and p. Candida mushrooms were placed in a solution of 2-bromo-2-nitropropan-1.3-diol of various concentrations for 24 hours, after which they conducted sterility studies (see table 2).

Table 2. Sterility Test Results Microorganism Inhibition of the growth of microorganisms depending on the concentration of a solution of 2-bromo-2-nitropropan-1.3-diol 0.5% one% 2% St.aureus no growth no growth no growth E.coli no growth no growth no growth Ent.faecalis growth on the 4th day no growth no growth Mushrooms p. Candida no growth no growth no growth

The test results show that the proposed method has a good sterilizing effect - a 1.0-2.0% solution of 2-bromo-2-nitropropane-1.3-diol inhibits the growth of all microorganisms.

To study the effect of the proposed sterilization method on the structure of the biomaterial, a histological examination of the porcine aortic valve cusps and cattle xenopericardium samples preserved in experimental solutions was performed. Storage of the biomaterial processed by the proposed method does not adversely affect the biomaterial — the collagen fibers are crimped and compact.

The proposed method of sterilization and storage of biological prostheses does not provoke calcium-binding activity of the biomaterial. 60 days after the implantation of samples processed by the proposed method under the skin of Vistar rats, the amount of calcium in the biomaterial is equal to metabolic and amounted to 2.47 + 0.21 mmk / mg dry tissue.

The proposed method does not reduce the elastic properties of the biomaterial pre-preserved with a solution of DEE (see table 3).

Table 3. Strength and elasticity indicators of biomaterial Processing method Strength (MPa) Elongation (E%) DEE solution (prototype) 6.8 ± 0.5 40.0 ± 1.1 A solution of DEE + 2-bromo-2-nitropropane-1.3-diol (according to the proposed method) 6.4 ± 0.7 43.0 ± 2.2

The use of 2-bromo-2-nitropropan-1.3-diol in the range of 0.01-2.0% is due to the fact that a concentration below 0.01% does not have the necessary sterilizing effect, and use above 2% is not technologically advanced.

The use of a solution with a pH of 4.0-8.0 allows you to maintain a stable concentration of the sterilizing solution over a long period of storage and has values close to physiological.

The advantage of the proposed method is to reduce the time of washing the bioprosthesis before implantation, which reduces the time of the operation. To wash the bioprosthesis from a sterilizing solution of 2-bromo-2-nitropropane-1.3-diol, it is necessary in 400 ml of a sterile 0.9% sodium chloride solution for 10 minutes with a double change of the solution after 5 minutes.

Claims (1)

A method of sterilization and preimplantation storage of biological prostheses for cardiovascular surgery, comprising washing a previously preserved biological prosthesis in a solution of a sterile 0.9% sodium chloride solution and placing it in a sterilizing agent on phosphate buffer, characterized in that a bactericidal agent is used as the sterilizing agent preparation 2-bromo-2-nitropropane-1,3 diol, prepared on 0.05-0.2 M phosphate buffer at a pH of 4.0-8.0 at a concentration of 0.01-2.0% at a temperature of 5-40 ° C.