RU2633062C1 - Method of pre-implant storage of biological prostheses for cardiovascular surgery - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: presented method involves washing of a pre-preserved biological prosthesis in a solution of a sterile 0.9% sodium chloride solution and placement in a sterilizing agent on phosphate buffer. At that, a mixture of bactericidal preparations consisting of ethylparaben, methylparaben, propylparaben and phenoxyethanol prepared on 0.05-2.0 M phosphate buffer and containing 5-20% of ethanol at pH 4.0-8.0 in the concentration of 0.2-2.0% and temperature of 5-40°C is used as a sterilizing agent.

EFFECT: increased strength of the biomaterial during storage and reduced time of bioprosthesis washing before implantation.

3 cl, 2 tbl, 2 ex

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 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. In addition, the preservation and storage of bioprostheses for cardiovascular surgery in a solution of glutaraldehyde provokes the formation of calcium phosphate in biological tissues, which can lead to bioprosthesis dysfunction after implantation.

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) (US Pat. No. 20088767, Russian Federation. Federation: IPC A01N 1/00. Method of preservation of biological tissue for prosthetics of heart valves and blood vessels [Text] / Barbarsh L.S., Novikova S.P., Zhuravleva I.Yu. et al .; patent holder Barbarash L.S. (RU) - No. 5024513/14; filed January 23, 1992; published March 15, 1994, Bulletin 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. The disadvantage of this method is the duration of the washing regime, which leads to an increase in operation time.

A known method of sterilization and preimplantation storage of biological prostheses of heart valves and blood vessels in a 0.01-2.0% solution of 2-bromo-2-nitropropane-1,3-diol in phosphate buffer (US Pat. No. 2357766, Russian Federation, IPC A61N 1/02, A61L 27/00. Method for sterilization and preimplantation storage of biological prostheses for cardiovascular surgery; copyright holder I. Zhuravleva (RU). - No. 2007125732/15; application 06.07.07, publ. 10.06.09) in which pre-preserved biological prostheses are placed in a 0.01-2.0% solution of 2-bromo-2-nitropropane-1,3-diol prepared on buffered saline, and stored in this solution until implantation.

The disadvantages of this method include the fact that the drug 2-bromo-2-nitropropane-1,3-diol does not have a sporocidal effect, and therefore cannot provide a sterilizing effect. In addition, long-term storage (more than 30 days) of biomaterial in a solution of 2-bromo-2-nitropropane-1,3-diol leads to a change in the color of the biological tissue from white to dark yellow and gives it rigidity.

A known method of sterilization and preimplantation storage of bioprostheses of the heart valve or blood vessels made of chemically stabilized xenogenic tissue, in which the products are placed for sterilization and storage until implantation in a solution of 2-3-bis (hydroxymethyl) -quinoxaline-1,4-dioxide at a temperature from 16 to 40 ° C (US Pat. No. 2457867, Russian Federation: MCP A61L 2/16, A61L 27/00, A61K 31/498. Method for sterilization and preimplantation storage of biological prostheses from xenogenic and allogeneic tissue for cardiovascular surgeons [Text] / Kostava V. T., Bakuleva N.P., Lyutova I.G. et al .; patent holder: Institution of the Russian Academy of Medical Sciences Scientific Center for Cardiovascular Surgery named after AN Bakulev RAMS (RU) No. 2011117782/15; 05/05/2011; publ. 08/10/2012, bull. No. 22). Before implantation, the bioprosthesis is placed in 500 ml of a sterile 0.9% sodium chloride solution for at least 30 seconds. The drug 2-3-bis (hydroxymethyl) -quinoxaline-1,4-dioxide has a powerful antibacterial and bacteriostatic effect, acts on bacterial strains resistant to other chemotherapy drugs, including antibiotics.

The disadvantages of this method include the high toxicity of 2-3-bis (hydroxymethyl) -quinoxaline-1,4-dioxide, this drug also has teratogenic, embryotoxic and mutagenic effects, is strictly contraindicated in children. For storage of biprostheses, an aqueous solution of 2-3-bis (hydroxymethyl) -quinoxaline-1,4-dioxide is used, which has an osmolarity of the solution much lower than the blood plasma in which it will be operated after implantation. Low osmolarity of the solution for storing bioprostheses can lead to edema biokani, which can cause prosthesis dysfunction after implantation.

Closest to the claimed method is a method for storing biological prostheses in a solution containing methyl and propyl parabens (US 5188834, CL A61L 27/36, A61L 27/00; A61F 002/02 Method of preparing a biological implantation material. Inventors .: Grimm ; Michael (AT), Eybl; Elisabeth (AT), Griesmacher; Andrea (AT), Grabenwoger; Martin (AT), Muller; Mathias M. (AT), Wolner; Ernst (AT); Assignee: Sorin Biomedica SpA (IT ), Filed 05/30/90, Date of patent 02/23/93). The essence of this method is that a solution containing 0.02% propyl paraben and 0.18% methyl paraben dissolved in phosphate buffer is used to store bioprostheses.

The disadvantages of this method include low concentrations of parabens, which may not have a sufficient antibacterial, bacteriostatic and fungicidal effect, since these substances partially lose their activity when dissolved in water and in contact with proteins. In addition, the phosphate buffer has a low osmolarity, which can lead to edema of the biological tissue during storage of bioprostheses and, as a result, provoke dysfunction of products after implantation.

The technical result of the invention is to enhance the sterilizing effect during storage and to reduce the time of washing the bioprostheses from the preservation solution before implantation, by using a mixture of bactericidal preparations prepared in 0.05-0.2 M phosphate buffer with the addition of ethyl alcohol.

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 with the addition of ethyl alcohol.

The difference is that a mixture of bactericidal preparations is used as a sterilizing agent: ethyl paraben, methyl paraben, propyl paraben and phenoxyethanol, prepared on 0.05-2.0 M phosphate buffer, containing 5-20% ethanol at pH 4.0-8.0 at a concentration of 0.2-2.0% and a temperature of 5-40 ° C.

The proposed method allows to obtain a solution for sterilization and storage of biological prostheses with high antibacterial, bacteriostatic, fungicidal and anti-spore activity, without negative impact on the structure and properties of pre-preserved biomaterial. The addition of ethyl alcohol to the solution for storing bioprostheses makes it possible to increase the osmolarity of the solution to blood plasma values, improves the solubility of the preparations used, and complements the sterilizing effect.

Used sterilizing agents are chemically synthesized substances and are effective bactericidal agents against gram-positive and gram-negative bacteria, are also active against various fungal flora and mold fungi, have strong antiseptic properties. In combination with each other, they enhance their antibacterial effect and have low toxicity. In the cosmetic industry, these preparations and their mixtures are widely used as a preservative in the manufacture of cleaning products for children, makeup remover, mouthwash, and the solution is stable during long-term storage.

Washing of one bioprosthesis before implantation can be carried out three times in 500 ml of 0.9% NaCl solution in one minute, so the total washing time will be 3 minutes.

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 put into storage in a 1% solution of a mixture of sterilizing agents containing 4 g of methyl paraben, 2 g of ethyl paraben, 2 g of propyl paraben, 2 g phenoxyethanol, 100 g of 95% ethyl alcohol (10% of the mass fraction of the solution) and 890 g of 0.1 M phosphate buffer.

Example 2. 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 0.5% solution of a mixture of sterilizing agents containing 3.5 g of methyl paraben, 1.5 g of ethyl paraben, 150 g of 95% ethyl alcohol (15% to the mass fraction of the solution) and 845 g of 0.1 M phosphate buffer.

To assess the sterilizing effect, bacteriological tests were carried out - samples of biomaterial contaminated for 24 hours St.aureus, E. coli, Ent.faecalis, Kl. pheumoniae, Acin. baumani and mushrooms p. Candida albicans were placed in 0.5% and 1% solutions of methylparaben / ethylparaben and methylparaben / ethylparaben / propylparaben / phenoxyethanol mixtures for 48 hours, after which they were tested for sterility (see table 1).

The test results show that the proposed method has a good sterilizing effect of 0.5-1.0% solutions of the mixture and ethyl paraben / methyl paraben and a solution of the mixture of ethyl paraben / methyl paraben / propyl paraben / phenoxyethanol at a temperature of 5-40 ° C inhibits the growth of all microorganisms and fungi.

To study the effect of the proposed method of sterilization on the structure of the biomaterial, a histological study of xenopericardium and the internal thoracic artery of cattle was carried out after storage in experimental solutions for 30 days. 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 treated with the proposed method under the skin of Vistar rats, the amount of calcium in the biomaterial is equal to metabolic and did not exceed 1.25 ± 0.21 mmk / mg of dry tissue.

The proposed method increases the strength of the biomaterial pre-preserved with a solution of DEE (see table 2).

The use of mixtures of ethyl paraben, methyl paraben, propyl paraben and phenoxyethanol in the range of 0.2-2.0% is due to the fact that a concentration below 0.2% does not have the necessary sterilizing effect, and use of more than 2% is not technologically advanced.

Using a solution with a pH of 4.0-8.0 at a temperature of 5-40 ° C allows you to maintain a stable concentration of the sterilizing solution over a long period of storage. During long-term storage (30 days or more), the biomaterial retains sterility, the structure of the collagen matrix, the strength of the biomaterial increases, the appearance does not change.

The advantage of the proposed method is to enhance the sterilizing effect during storage, increase the strength of the biomaterial and reduce the time to wash bioprostheses before implantation, which reduces the time of the operation. To wash the bioprosthesis from a sterilizing solution of mixtures of ethyl paraben / methyl paraben or ethyl paraben / methyl paraben / propyl paraben / phenoxyethanol, it is necessary in 500 ml of a sterile 0.9% sodium chloride solution for 3 minutes with a double change of solution after 1 minute.

Claims (3)

1. The method of preimplantation storage of biological prostheses for cardiovascular surgery, including washing the native tissue, preserving it in a crosslinking and sterilizing agent, followed by washing and storage until implantation in a sterilizing solution of propyl paraben and methyl paraben prepared on a phosphate buffer, characterized in that in sterilization paraben solution in addition to the mass of the solution is introduced ethyl paraben in a mass fraction of 0.02-0.4%, phenoxyethanol in a mass fraction of 0.02-0.4%, as well as ethyl alcohol in a mass of les 5-20%, the solution is prepared in 0.05-2.0 M phosphate buffer at pH 4.0-8.0 to a concentration of 0.2-2.0% and a temperature of 5-40 ° C. 2. The method of preimplantation storage of biological prostheses according to claim 1, characterized in that the content of propyl paraben in relation to the weight of the solution is 0.04-0.4%. 3. The method of preimplantation storage of biological prostheses according to claim 1, characterized in that the content of methyl paraben relative to the weight of the solution is 0.08-0.8%.