RU2609735C1 - Method of optimisation of photodynamic therapy of purulent wounds (versions) - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: group can be used for photodynamic therapy (PDT) of purulent wounds. To treat purulent wounds, infected mainly by Gram-positive bacteria, preparation in form of hydrogel based on fotoditazin and bio-soluble polymer of chitosan sulphate is used with the following ratio of components, wt %: fotoditazin - 0.2-1.0; chitosan sulphate - 1.5-3.0; water - the remaining part. PDT is realised in two sessions. To treat purulent wounds, infected mainly by Gram-negative bacteria preparation in form of hydrogel based on fotoditazin and bio-soluble polymer pluronic F127 is used with the following ratio of components, wt%: fotoditazin - 0.2-1.0; pluronic F127 - 3.0-4.0; water - the remaining part. PDT is realised in two sessions as well. To treat purulent wounds, infected with bacteria of both groups by Gram, PDT is realised in two sessions, with application for the first session of photodynamic therapy of preparation in form of hydrogel, based on fotoditazin and bio-soluble polymer pluronic F127 with the following ratio of components, wt%: photosensitiser - 0.2-1.0; pluronic F127 -1.5-4.0; water - the remaining part; for the second session of photodynamic therapy applied is preparation in form of hydrogel, based on fotoditazin and bio-soluble polymer of chitosan sulphate, with the following ratio of components, wt %: photosensitiser - 0.2-1.0; chitosan sulphate - 1.5-3.0; water - the remaining part.

EFFECT: increase of treatment efficiency due to selective impact on Gram-positive and Gram-negative bacteria, reduction of concentration of applied photosensitiser in preparation, applied for carrying out PDT, prevention of growth of remaining microflora in wound and development of secondary necrosis.

6 cl, 1 dwg, 1 tbl, 3 ex

Description

The invention relates to medicine, in particular to methods for treating purulent wounds by photodynamic therapy (PDT).

The problem of treating local bacterial infections - purulent-inflammatory diseases of the soft tissues - remains relevant, despite the successes of clinical medicine and pharmacological science. There are many antibacterial drugs, including antibiotics, but their use for the treatment of diseases of microbial etiology leads to the appearance of microorganisms resistant to chemotherapy. In this regard, the PDT method is becoming increasingly important in the treatment of local infectious processes. The advantage of the PDT method is the lack of development of resistance of microorganisms to this type of treatment. The local nature of the bactericidal effect, which is limited by the wound surface, is also important, which helps to avoid a side effect - a fatal systemic effect on the normal flora of the body, which is typical for the use of antibiotics and antiseptics. In addition, the effectiveness of the antimicrobial action of PDT does not decrease with prolonged treatment of chronic suppurative inflammatory diseases of the soft tissues.

Currently, a fairly large number of photosensitizers (FS) and means based on FS for PDT are known. For the treatment of purulent wounds, the greatest use was found in the form of hydrogels in which PS was immobilized on a bio-soluble polymer (RU 2286780, IPC A61K 31/409, 11/10/2006; RU 2314806, IPC A61K 31/409, 01/20/2008; RU 2396994, IPC A61N 5/067, A61K 31/409, 08/20/2010; RU 2465899, A61K 31/40, 11/10/2012; RU 2530589, A61K 31/409, A61P 17/02, 10/10/2014). The use of FS in the form of a gel simplifies the PDT procedure and allows you to accurately localize the FS within the wound surface.

Known methods for treating purulent wounds by the PDT method, including irradiating a wound with a laser at a wavelength of 660 ± 0.03 nm, a power density of ~ 1.0 W / cm ² and an energy density of 25-35 J / cm ² , differ in the means used for PDT.

For example, there is a method of treating purulent wounds described in patent RU 2286780, publ. 11/10/2006. The method includes the following: a Photoditazin gel based on methylhydroxyethyl cellulose ethers (manufactured by Veta-Grand company) containing 0.5-1.5% glucurin salt of chlorin E6 is introduced into the purulent wound, the gel is applied for 2 hours. Next, the laser is irradiated with a wound. The disadvantages of this known method are the high concentration of PS in the PDT agent used and the long duration of its exposure to the wound, which leads to a significant accumulation of PS in healthy tissues.

In patent RU 2396994, publ. 08/20/2010 as a means for PDT, a modified Photoditazin gel based on methylhydroxyethyl cellulose ethers containing 0.5-1.5% dimethylglucamine salt of chlorin E6 is used, for which it is mixed with a 25% aqueous solution before applying the gel to the wound surface polyethylene oxide in a volumetric ratio gel: a solution of polyethylene oxide 10: 2-3. The modified gel is kept on the surface of the wound for 15-30 minutes, after which the remnants of the unabsorbed gel are washed off with an antiseptic solution and laser irradiation is performed. The method allows to reduce the aging time of the means for PDT on the surface of the wound, which significantly reduces the content of FS in healthy tissues. The disadvantages of this method are its complexity, lack of effectiveness and a high concentration of PS in the PDT agent used.

In the method of treatment of purulent wounds described in patent RU 2530589, publ. 10/10/2014, the means for PDT before laser irradiation is not removed from the surface of the wound. As an agent for PDT, an aqueous gel is used, including the dimethylglucamine salt of chlorin E6 and a bio-soluble polymer immobilized on hydroxyapatite nanoparticles. The bio-soluble polymer is a mixture of Pluronic F127 and sodium carboxymethyl cellulose. The disadvantage of this method of treatment is the difficulty of obtaining used funds for PDT.

In all known methods of treating purulent wounds using the PDT method, PDT agents are used that do not have a selective effect on the gram-negative or gram-positive group of bacteria, which reduces their effectiveness. To date, no studies have been conducted on the effect of the properties of PDT agents used on pathogens of various group affiliation in order to search for agents for treating purulent wounds using the PDT method, which have a selective effect on either gram-positive or gram-negative bacteria.

The objective of the invention is to develop a method of photodynamic therapy of purulent wounds - options that have a selective effect on either gram-positive or gram-negative bacteria, which will increase the effectiveness of treatment with PDT and will reduce the concentration of PS in the agent used in PDT.

The solution to this problem is achieved:

- the proposed method of photodynamic therapy of purulent wounds, in which according to the invention, in the treatment of purulent wounds infected mainly with gram-positive bacteria, a hydrogel based on photoditazine and a bio-soluble polymer of chitosan sulfate is used in the following ratio of components, wt. %:

photoditazine 0.2-1.0 chitosan sulfate 1.5-3.0 water rest

while photodynamic therapy is carried out in two sessions.

Photodynamic therapy is carried out using laser radiation with a power density of not more than 1.5 W / cm ² and with an energy density of 25-30 J / cm ² ;

- the proposed method of photodynamic therapy of purulent wounds, in which according to the invention, in the treatment of purulent wounds infected mainly with gram-negative bacteria, a hydrogel-based agent based on photoditazine and a bio-soluble pluronic polymer F127 is used in the following ratio of components, wt. %:

photoditazine 0.2-1.0 Pluronic F127 3.0-4.0 water rest

while photodynamic therapy is carried out in two sessions.

Photodynamic therapy is carried out using laser radiation with a power density of not more than 1.5 W / cm ² and with an energy density of 25-30 J / cm ² ;

- the proposed method of photodynamic therapy of purulent wounds, in which according to the invention in the treatment of purulent wounds infected with bacteria of both groups according to Gram, photodynamic therapy is carried out in two sessions, while for the first session of photodynamic therapy, a means in the form of a hydrogel based on photoditazine and a bio-soluble pluronic polymer is used F127 in the following ratio of components, wt. %:

photosensitizer 0.2-1.0 Pluronic F127 1.5-4.0 water rest

for the second session of photodynamic therapy using a tool in the form of a hydrogel based on photoditazine and a bio-soluble polymer of chitosan sulfate in the following ratio of components, wt. %:

photosensitizer 0.2-1.0 chitosan sulfate 1.5-3.0 water rest

Photodynamic therapy is carried out using laser radiation with a power density of not more than 1.5 W / cm ² and with an energy density of 25-30 J / cm ² .

When creating the invention, experimental studies were carried out, including in vivo, in which the effectiveness of the antibacterial action of various complexes of PS with bio-soluble polymers with respect to pyogenic flora of various group affiliation was studied. Experimentally determined the optimal ratio of the components used in the proposed method for PDT.

The comparative photocatalytic activity of various PSs and their complexes with various polymers was studied on the model reaction of tryptophan photooxidation under laser irradiation in an aqueous solution. The results showed that the investigated FS: photoditazine, dimegin, photogam slightly differ in photocatalytic activity, the most active is photoditazine (dimethylglucamine salt of chlorin E6). In the proposed method (options), you can use either photoditazine, or dimegin, or photogamy, photoditazine is most preferred.

Sodium salt of carboxymethyl cellulose, pluronic F127, polyvinyl alcohol, chitosan sulfate were used as biosoluble polymers to immobilize PS with them. The highest photocatalytic activity was observed for the complex of photoditazine with Pluronic F127, the smallest for complexes of PS with polyvinyl alcohol, therefore, it was not studied in vivo experiments.

In in vivo experiments, we used white laboratory rats. In accordance with the European Convention (Strasbourg, 1986) and the Helsinki Declaration of the World Medical Association for the Humane Treatment of Animals (2000), as well as the requirements of Order No. 267 of the Ministry of Health of the Russian Federation of June 19, 2003, “Rules for the Treatment, Maintenance, Anesthesia and Killing of Experimental Animals »The animals were kept under standard vivarium conditions, one individual in a cage, fed with complex granulated laboratory food with constant access to water.

On the experimental model of infected full-layer planar skin wounds, a comparative study of the dynamics of purulent wound healing by the PDT method using FS-bio-soluble polymer complexes with different chemical structures of the components was performed to identify the gram selective action of the complex on a particular group of bacteria.

A model of a full-layer planar wound was used as an experimental model of a wound (L.I. Slutsky, 1969; A.V. Shekhter et al., 2005). Animals were anesthetized by intramuscular injection of a solution of zoletil (Zoletil 100, Virbac SA, Italia) at a rate of 6 mg of active substance per 1 kg of animal body weight in combination with rometar (Rometar, Spofa, Praha) at a rate of 0.5 ml per 1 kg of body weight. A concentric (~ 8-10 mm in diameter) flap of skin with subcutaneous tissue right up to its own fascia was dissected on a preliminary depilated back skin in the interscapular region using a stencil. A clutch-like Teflon ring was introduced into the defect formed. Thus, all animals received wounds of standard size, an area of 300 mm ² .

In accordance with the Methodological Recommendations for the experimental (preclinical) study of drugs for the local treatment of purulent wounds (Ministry of Health of the USSR, 1989), to create an infected (purulent) wound, Kocher's clamp injured his own fascia and muscles of the wound bottom and 0 was applied to its surface bounded by a ring , 5 ml of a suspension of microbial culture. A cellophane film was fixed along the upper cut of the cylindrical part of the ring to prevent drying of the wound and external contamination.

A suspension of daily associated microbial culture was used to infect wounds. The association contained pathogenic pathogens of different group affiliation:

- gram-positive bacteria - Staphylococcus aureus S7 (clinical strain);

- gram-negative bacteria - Escherichia coli ATCC 8739 (the standard strain used for testing antimicrobial activity) and Pseudomonas aeruginosa.

Five groups of experiments were performed (groups I and II - control) of 6 animals each using various means for treating wounds using the PDT method (in group I, the wounds were treated with chlorhexidine) (see table).

A day after the application of the wound and its infection, PDT sessions were started in groups II-V, and in the control group I, the wounds were treated with a chlorhexidine solution. PDT sessions were carried out as follows: the test agent was applied to the wound surface in the form of a hydrogel based on a photosensitizer and a bio-soluble polymer (in control group II, a 1% aqueous solution of photoditazine was applied) in an amount of 0.1 g per 1 cm ^{2 of the} wound surface; for 20 min and the wound surface was irradiated with low-intensity laser radiation of the domestic apparatus “Atkus-2” with a wavelength of 663 ± 0.03 nm at a power density of 1 W / cm ² and with an energy density of 25-30 J / cm ² .

Measurement of microbial contamination of experimental wounds in rats was performed:

- 24 hours after infection (before the 1st session of PDT);

- immediately after the 1st session of PDT;

- before the 2nd session of PDT, which was carried out a day after the 1st session;

- immediately after the 2nd session of PDT.

24 hours after infection (before the 1st session of PDT), the initial contamination of wounds in all groups of animals was almost the same and amounted to: for coccal flora 3.00 ± 0.05⋅10 ⁶ -3.80 ± 0.05⋅10 ⁶ E; for the association of Escherichia coli and Pseudomonas aeruginosa - 2.80 ± 0.05⋅10 ⁶ -5.00 ± 0.05⋅10 ⁶ E.

In control group I, the initial treatment of wounds with a chlorhexidine solution reduced the number of gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) to 4.20 ± 0.05 410 ⁴ U, but did not affect the number of staphylococci. Repeated treatment of wounds with chlorhexidine led to a slight decrease in the level of contamination of both coccal and rod flora.

In all experimental groups (III-V) and control group II, after the first PDT session, the presence of staphylococci decreased by a logarithmic parameter by 1.5-2 times. In groups II, IV, and V, the same was observed for gram-negative bacteria.

But in group III, where a complex of photoditazine with Pluronic F127 was used as a means for PDT, the number of germinated colonies of gram-negative rods was less than 10 bacteria / ml (<1.0 ± 0.05 0,010 Е) in the cultures from wounds. After the 2nd PDT session in group III, gram-negative bacteria were not sown, an additional decrease in the number of staphylococci was insignificant. Such results allow us to talk about the selectivity of the effects of the photoditazine-pluronic F127 complex during PDT with respect to gram-negative flora.

The 2nd PDT session in groups II, IV and V in relation to coccal infection led to uneven results: in groups II and IV (as in group III), an additional decrease in the number of staphylococci was insignificant, whereas in group V, where as a means for PDT, the photoditazine-sulfate chitosan complex was used; after the 2nd session of PDT, the coccal flora was practically not sown from the surface of the wounds: the number of CFU / ml was less than 1.0 ± 0.05⋅10 U (log CFU / ml <1), that is, in relation to gram-positive flora, the most effective is the complex photoditazine-sulfate chitosis ana.

The seeding rate of gram-negative bacteria in groups II, IV and V after the 2nd session of PDT also decreased, but not so much as for the photoditazine-pluronic F127 complex (group III). The complex photoditazine-sodium salt of carboxymethyl cellulose is not distinguished by either selectivity for microflora or high activity.

For clarity, the change in the quantitative indicators of bacterial contamination of the wounds of experimental animals during treatment is presented in the drawing: Figure A - effect of treatment on gram-positive microflora; chart B - the effect of treatment on gram-negative microflora.

The data obtained from a microbiological study of smears of wound exudate of experimental animals during treatment allowed us to develop the proposed method for optimizing PDT of purulent wounds (options).

To determine the optimal ratio of components in the PS-bio-soluble polymer complexes used in the proposed method (variants), we conducted studies on the model reaction of tryptophan photooxidation under laser irradiation in an aqueous solution. According to the results obtained during the experiment (the rate constant of tryptophan photooxidation was determined) it was found that the mass ratio of PS and chitosan sulfate in the complex should be at least 1:15, and PS and pluronic F127 should be at least 1:20, otherwise the rate of the photochemical reaction noticeably decreases . With an increase in the amount of PS in the complex to a ratio of 1: 3 for chitosan sulfate and up to 1: 4 for Pluronic F127, the photooxidation rate increases, but with a further increase in the content of PS, the reaction rate stops growing.

We give examples of the use of the present invention in the treatment of purulent wounds by PDT.

Example 1

Patient N., 24 years old, was admitted to the surgical infection department of City Clinical Hospital No. 51 with a diagnosis of scapular carbuncle on the right, type II diabetes mellitus, decompensation due to refusal to take drug therapy and alcohol abuse. Complaints at admission: pain and swelling in the right scapular region. From the anamnesis, it is known that for a long time he suffers from type II diabetes mellitus, during drug therapy with glucophage. Over the past 3 years marks an episode of the disease twice. 6 days before admission, she noted the appearance of a painful infiltrate in the right scapular region. Pain, edema and hyperemia increased, subfebrile fever appeared. The patient turned to the ambulance and was urgently hospitalized in a hospital. On examination: the condition is relatively satisfactory, body temperature 38.3 ° C. Leukocytosis 14.0 × 10 ⁹ / L. Locally: in the scapular region on the right there is an infiltrate 4.0 cm × 6.5 cm in size with pronounced perifocal inflammatory edema up to 5 cm from the outbreak. In the center of the infiltrate several purulent necrotic rods and pustules are determined. On palpation through pustules, pus is secreted, the symptoms of "sieve" and "bee honeycomb" are determined. Operation: performed primary surgical treatment of purulent foci. The carbuncle is excised within the healthy tissues, a wound with a size of 4.5 cm × 7.5 cm has formed. A culture of purulent discharge has been taken for microflora and sensitivity to antibacterial drugs. Antibiotic resistant strains of S. aureus were seeded.

The next day, the dressing was performed - there are fibrinous-purulent deposits, non-viable tissues in the bottom and on the walls of the wound, the wound is sanitized with antiseptic solutions. Applied to the wound surface in the form of a hydrogel in an amount of 0.1 g per 1 cm ² containing 0.5 wt. % photoditazine and 3.0 wt. % chitosan sulfate (water - the rest). The wound is covered with a sterile plastic dressing for 20 minutes. After that, the wound surface was illuminated by low-intensity laser radiation of the domestic Atkus-2 apparatus with a wavelength of 663 ± 0.03 nm at a power density of 1.0 W / cm ² and with an energy density of 30 J / cm ² . Then, a dressing was applied to the wound with a 1% aqueous solution of iodopiron. The next day, perifocal inflammatory phenomena significantly decreased, but in the area of the bottom of the wound areas of necrotic tissue remained. In accordance with the proposed method for optimizing PDT of purulent wounds, the session of laser PDT using the above means was repeated. After a second session of laser PDT, the wound cleansed of purulent necrotic masses, the active development of granulation tissue and marginal epithelization was noted. The patient was discharged in satisfactory condition on the 9th day after excision of the carbuncle, the postoperative wound in the stage of granulation and marginal epithelization. The patient was examined on the 20th day. The wound healed by secondary tension with a soft elastic scar.

Example 2

Patient S., 46 years old, was admitted to the Department of Surgical Infection GKB No. 51 with a diagnosis of Diabetic foot syndrome, mixed form. Wet gangrene of the left foot, type I diabetes mellitus, decompensation. Complaints at admission: pain, swelling and hyperemia in the left foot. From the anamnesis it is known that for a long time he suffers from type I diabetes, on insulin therapy. A week before admission, she “rubbed” her foot with shoes during long walks, after which edema, redness, and pain appeared at the site of damage. Then (according to the patient), the process spread to the entire foot and fever up to 39.5 ° C joined. On examination: a state of moderate severity, closer to severe, hyperthermia 38.2 ° C. Leukocytosis 20.0 × 10 ⁹ / L. Locally: the left foot is markedly enlarged due to lymphostasis, swollen, hyperemic, in the region of the head of the 1st metatarsal bone there is a fistulous opening, upon palpation from which creamy pus with a characteristic echarose smell comes. Ripple on the back of the foot is significantly reduced. X-ray of the left foot: osteoporosis, destruction of the head of the 1st and 2nd metatarsal bones. Operation: wedge-shaped incisions were made on the back and plantar surfaces of the left foot in the projection of the second finger, the tops of the sections are at the level of the middle third of the metatarsal bones. Sowing of purulent discharge to the microflora and sensitivity to antibacterial drugs were taken. The heads of the I and II metatarsal bones were resected with Liston forceps, the plantar aponeurosis was excised within the healthy tissues, the interdigital tendons, the flexors and extensor tendons of the right foot were excised throughout. The wound is washed with a 3% hydrogen peroxide solution. Hemostasis with firmware. An aseptic dressing is applied to the wound. Microflora plating result: Escherichia coli and Pseudomonas aeruginosa.

The next day, the dressing was performed - there are fibrinous-purulent deposits, non-viable tissues in the bottom and on the walls of the wound, the wound is sanitized with antiseptic solutions. Applied in the form of a hydrogel in the amount of 0.1 g per 1 cm ² containing 1.0 wt. % photoditazine and 3.0 wt. % pluronic F127 (water - the rest). The wound is covered with a sterile plastic dressing for 20 minutes. After that, the wound surface was illuminated by low-intensity laser radiation of the domestic Atkus-2 apparatus with a wavelength of 663 ± 0.03 nm at a power density of 1.0 W / cm ² and with an energy density of 30 J / cm ² . Then, a dressing was applied to the wound with a 1% aqueous solution of iodopiron. The patient is prescribed a course of antibacterial therapy. After a repeated PDT session, the patient noted an improvement in the form of a decrease in pain, swelling and lack of fever. Locally: hyperemia and edema around the wound decreased, the amount of discharge from the wound decreased, marginal epithelization and the appearance of granulation tissue were noted. The patient was discharged in satisfactory condition on the 15th day.

Postoperative wound in the granulation and marginal epithelialization stage. The patient was examined on the 30th day. The wound healed by secondary tension with a soft elastic scar. The supporting function of the limb is saved.

Example 3

Patient D., 55 years old, was admitted to the Department of Surgical Infection GKB No. 51 with a diagnosis of Chronic lymphovenous insufficiency. Trophic ulcers of the right lower leg. A history of a long smoking episode. Complaints on admission: pain, swelling and the presence of ulcers in the right lower leg. From the anamnesis it is known that the patient suffers from chronic lymphatic venous insufficiency for a long time, he was treated conservatively at the place of residence. About a year ago, he noted changes in skin color, the appearance of local areas of pigmentation, and then the appearance of ulcers. On examination: moderate severity, body temperature 37.5 ° C. Leukocytosis 17.0 × 10 ⁹ / L. Locally: the right tibia is markedly edematous, brightly hyperemic. In the region of the right tibia along the anterior surface there are multiple purulent-necrotic trophic ulcers of various diameters from 2 to 10 cm, along the posterior surface, starting from N / A to the popliteal fossa, there is an infiltrate, fluctuation is noted. Operation: under iv anesthesia, the wounds were inspected on the front and back surfaces of the right lower leg. Intraoperative wounds on the anterior surface were combined and the total area was 25 cm × 6 cm × 2 cm, a purulent sagging was opened on the posterior surface in the region of the upper third of the wound, up to 30 ml of purulent discharge was taken (culture of purulent discharge was taken on microflora and sensitivity to antibacterial drugs ), the bottom is represented by necrosis of the subcutaneous fat, fascia of the lower leg. A necrectomy was performed within healthy tissues. All necrotic subcutaneous fat is removed using an acute spoon. The wounds are sanitized with solutions of antiseptics and loosely swabbed with hydrogen peroxide. Control for hemostasis is dry. Aseptic dressing. Microflora plating result: Staphylococcus Aureus, Escherichia coli and Pseudomonas aeruginosa.

On the next day, purulent-necrotic fusion of soft tissues, necrosis of tendons and subcutaneous tissue are observed in the ligation. All purulent necrotic masses are removed within healthy tissues. Applied in the form of a hydrogel in the amount of 0.1 g per 1 cm ² containing 1.0 wt. % photoditazine and 3.0 wt. % pluronic F127 (water - the rest). The wound is covered with a sterile plastic dressing for 20 minutes. After that, the wound surface was illuminated by low-intensity laser radiation of the domestic Atkus-2 apparatus with a wavelength of 663 ± 0.03 nm at a power density of 1.0 W / cm ² and with an energy density of 30 J / cm ² . A bandage with a 1% solution of iodopiron is applied to the wound. The patient is prescribed a course of antibacterial therapy. At the next change of dressings, the number of necrosis and purulent-necrotic tissue decreased significantly. The patient underwent a second PDT session using a hydrogel agent in an amount of 0.1 g per 1 cm ² containing 0.5 wt. % photoditazine and 3.0 wt. % chitosan sulfate (water - the rest). The patient was discharged in satisfactory condition on the 13th day after hospitalization. Locally: postoperative wounds without signs of inflammation, actively granulate. When examined on the 22nd day, the wounds completely healed by secondary tension with an elastic scar without the use of plastic surgery.

Thus, the proposed method for optimizing the photodynamic therapy of purulent wounds (options) has a selective effect on either gram-positive or gram-negative bacteria and provides an increase in the effectiveness of treatment with PDT. The method (options) allows you to prevent the growth in the wound of residual microflora and the development of secondary necrosis, allows you to reduce the concentration of PS in the tool used during PDT.

Claims (13)

1. The method of photodynamic therapy of purulent wounds, characterized in that in the treatment of purulent wounds infected mainly by gram-positive bacteria, use is made of a hydrogel based on photoditazine and a bio-soluble polymer of chitosan sulfate in the following ratio of components, wt. %: photoditazine 0.2-1.0 chitosan sulfate 1.5-3.0 water rest while photodynamic therapy is carried out in two sessions. 2. The method according to p. 1, characterized in that the photodynamic therapy is carried out using laser radiation with a power density of 1.0 W / cm ² and with an energy density of 30 J / cm ² . 3. The method of photodynamic therapy of purulent wounds, characterized in that in the treatment of purulent wounds infected mainly by gram-negative bacteria, use is made of a hydrogel based on photoditazine and a biosoluble polymer Pluronic F127 in the following ratio of components, wt. %: photoditazine 0.2-1.0 Pluronic F127 3.0-4.0 water rest while photodynamic therapy is carried out in two sessions. 4. The method according to p. 3, characterized in that the photodynamic therapy is carried out using laser radiation with a power density of 1.0 W / cm ² and with an energy density of 30 J / cm ² . 5. The method of photodynamic therapy of purulent wounds, characterized in that in the treatment of purulent wounds infected with bacteria of both groups according to Gram, photodynamic therapy is carried out in two sessions, while for the first session of photodynamic therapy, a means in the form of a hydrogel based on photoditazine and a bio-soluble pluronic polymer is used F127 in the following ratio of components, wt. %: photosensitizer 0.2-1.0 Pluronic F127 1.5-4.0 water rest for the second session of photodynamic therapy using a tool in the form of a hydrogel based on photoditazine and a bio-soluble polymer of chitosan sulfate, in the following ratio, wt. %: photosensitizer 0.2-1.0 chitosan sulfate 1.5-3.0 water rest 6. The method according to p. 5, characterized in that the photodynamic therapy is carried out using laser radiation with a power density of 1.0 W / cm ² and with an energy density of 30 J / cm ² .

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