PHARMACEUTICAL MICROBIOLOGY - V. A. Galynkin - 2015

PART III. MICROBIOLOGICAL ASPECTS OF PHARMACEUTICAL MANUFACTURING

CHAPTER 24. CONTROL OF CONTAMINATING MICROORGANISMS IN PHARMACEUTICAL PRODUCTS

24.1 Effects of Physical and Chemical Factors on Microorganisms

Microorganisms exhibit significantly greater tolerance to physical and environmental Chemical factors than plants and animals. Certain Bacteria are capable of proliferating at temperatures ranging from -12°C to +104°C, across a pH range of 1 to 13, and under hydrostatic pressures from 0 to 1400 atm; they survive intense radiation and inhabit both distilled Water and saturated salt solutions. At the same time, each microbial species possesses genetically determined thresholds for specific environmental impacts, encompassing zones of optimum, growth inhibition, and lethality.

24.1.1 Physical Factors Favorable for Microbial growth

Temperature. Microorganisms are classified into three groups based on the temperature range most suitable for their GROWTH AND REPRODUCTION: psychrophiles (cold-loving organisms) have an optimal growth temperature of 10-15°C and exist as free-living microbes or parasites of cold-blooded animals. Among psychrophiles, there are species pathogenic to humans, such as Yersinia enterocolytica. This microorganism can multiply rapidly on food products within household refrigerators, where low temperatures (below 10°C) promote the Selection of virulent strains. Psychrophilic variants of Klebsiella and Pseudomonas exhibit similar properties.

Mesophiles inhabit primarily The Human Body and warm-blooded animals. Their optimal growth temperature is 30-37°C, with a maximum of 43-45°C and a minimum of 15-20°C. They generally do not multiply in the external environment. Thermophiles (heat-loving microorganisms) have an optimal growth zone of 50-60°C, an upper growth-inhibition threshold of 75°C, and a lower threshold of 45°C. Thermophiles are incapable of proliferating within a living host and thus hold no medical significance; however, certain thermophilic species are considered promising for biotechnology as producers of BIOLOGICALLY ACTIVE SUBSTANCES. Thermophiles inhabit hot springs and participate in the self-heating processes of manure, hay, and grain. The presence of a high concentration of thermophiles in soil indicates contamination by manure and compost. Extreme thermophiles inhabit hot springs at temperatures up to 104°C.

Reaction of the medium (pH). For most bacteria, the optimal environment for growth and reproduction consists of neutral pH values (pH 6.8-7.0), whereas Fungi prefer slightly acidic conditions with a pH of 5.0-6.0. During reproduction, the pH typically shifts toward the acidic range; growth slows down and may eventually lead to Cell death. The damaging mechanism of extreme pH involves the Denaturation of Enzymes by hydroxyl ions and the disruption of the osmotic barrier of cell membranes.

Moisture. Environments with high water activity are favorable for the active proliferation of microorganisms. A decrease in environmental moisture prompts Cells to enter a resting stage, subsequently resulting in death. Capsular microbial forms, spores, and cysts exhibit high resistance to desiccation. Vacuum-drying from the frozen state—lyophilization—is utilized to prolong viability and preserve microorganisms. Lyophilized cultures and immunobiological preparations remain stable for extended periods without altering their properties.

24.1.2 Microbial Sensitivity to Damaging Factors

Exposure to damaging factors results in microbial death. A microbial cell is considered dead if it has lost its reproductive capacity. Bactericidal, fungicidal, and virucidal actions are distinguished depending on the destruction of the respective targets. To evaluate the lethality of a given factor, the D₁₀ value is employed, which represents the exposure time at a specified temperature or the radiation dose required to reduce The Cell concentration tenfold, i.e., to eliminate 90% of the cells in a population.

24.1.3 Effect of High Temperatures on Microorganisms

Elevated temperatures induce denaturation and destruction of vital cellular molecules; steam sterilization under pressure triggers Hydrolysis reactions, whereas dry heat drives oxidation reactions.

Based on their resistance levels, microorganisms are categorized into the following groups:

1) sensitive — non-spore-forming bacteria, Molds, Viruses;

2) mildly resistant — hepatitis viruses, Clostridium perfringens spores;

3) highly resistant — C. tetani;

4) extremely resistant — Bacillus subtilis spores, C. botulinum;

5) most resistant — B. stearothermophilus spores, soil thermophiles, Prions.

The thermal stability of identical microorganisms can vary depending on moisture availability and The properties of the suspending medium. The susceptibility of a single microbial species to high temperatures depends on several factors:

1) strain-specific differences; for instance, the thermal death time for C. tetani spores treated with steam at 100°C ranges from 5 to 90 minutes;

2) the phase state of the cells, which is linked to The activity of their metabolic processes;

3) the aggregation state of the cells, specifically the presence of clusters (conglomerates) that exhibit greater resistance than individual cells;

4) the type of thermal Treatment: at equivalent temperatures, dry heat is less effective than moist heat; microbial death in a moist environment occurs due to the denaturation of Nucleic Acids and Proteins, and membrane damage, whereas dry heat exposure activates oxidative processes (pyrolysis);

5) the COMPOSITION OF THE heat treatment medium, as many organic and inorganic substances exert a protective effect on the cell, for example, NaCl, magnesium salts, fats, surface-active agents, etc.;

6) the pH value of the medium; for instance, at 100°С, certain spore-forming microorganisms are killed at pH 6-7 within 2.5 hours, whereas at pH 3-3.5 they perish in 30 minutes.

24.1.4 Effect of radiant energy on microorganisms

Both ionizing and non-ionizing radiation exhibit antimicrobial activity. Non-ionizing radiation includes infrared (IR) and ultraviolet (UV) irradiation. IR rays have a relatively long wavelength and, consequently, low energy. They produce predominantly a thermal effect.

UV rays possess higher energy and are capable of inducing photochemical alterations in both substrate molecules and microbial cells. Rays with a wavelength of 250-260 nm are the most effective. Different species and forms of microorganisms exhibit varying sensitivity to the same radiation dose. Pigmented microorganisms as well as Spore Forms of bacteria and fungi display heightened resistance. The efficacy of UV irradiation depends on the radiation dose—that is, The amount of energy absorbed by the cell—The Nature of the irradiated object, and environmental conditions (pH of the medium, substrate moisture, temperature, and the presence of cell-protecting substances).

The lethal mechanism of UV irradiation is associated with The formation of thymine dimers and other pyrimidine bases in DNA, which leads to the cessation of Replication and subsequent cell death. It is important to bear in mind The phenomenon of photoreactivation driven by daylight, which activates enzymes that catalyze dimer splitting, thereby restoring cell viability. In addition to the Direct impact of UV radiation, an indirect effect is also possible through the generation of ozone, hydrogen peroxide, and other bactericidal substances within the treated substrate.

Ionizing radiation comprises γ-radiation and accelerated electrons. Radioactive elements such as Co⁶⁰ and Cs¹³⁷ serve as sources of γ-radiation. The Radioresistance of various microbial species differs significantly. As a rule, Gram-negative cells are more sensitive than Gram-positive ones; vegetative cells are the least resistant, whereas fungi and Yeasts, followed by bacterial spores and viruses, exhibit higher resilience. A notable example is the radioresistant microorganism Micrococcus radiodurans, which has adapted to life within nuclear power plant reactors. The radiosensitivity of cells belonging to the same species depends on cell age (young cells are more sensitive than mature ones), the composition of the medium, and the absorbed radiation dose.

The absorbed radiation dose refers to the amount of energy absorbed per unit mass of the medium through which the radiation passes. The unit of radiation dose measurement is the rad (radiation absorbed dose); 1 rad is equivalent to 100 erg/g, and 1 Mrad = 10⁶ rad = 10 kGy (kilogray).

For radiosensitive microorganisms, D₁₀ <1 kGy, whereas for radioresistant ones, D₁₀ is approximately 2.3 kGy. The sterilizing dose ranges from 25 to 35 kGy. Cell death is caused by numerous Chemical Reactions Involving water radiolysis products generated within both the cell and the substrate, which include highly reactive free radicals of atomic oxygen and peroxides.

24.1.5 Action of chemical substances with non-specific antimicrobial activity on microorganisms

The effectiveness of a chemical substance against a microorganism depends on its species and strain. Certain chemicals exhibit a broad spectrum of antimicrobial activity. A highly effective example is Ethylene oxide, which impacts spore and vegetative forms alike. Strain-related differences in microbial susceptibility to chemical agents can be either genotypic or phenotypic. Alterations in the genotype are frequently governed by Plasmids and Transposons that confer sensitivity (or resistance) to chemical treatments. Phenotypic differences are related to medium composition, pH, temperature, and the cell concentration within the object. Key Factors Determining the efficacy of a chemical substance on cells include its concentration, medium composition, contact time with the microorganism, and temperature.

24.2 Asepsis. Antisepsis. Sterilization.

Asepsis refers to a set of measures aimed at preventing The entry of microbes onto or into a given object—such as an operational field, microbiological safety cabinet, specific production facilities, or sterile solutions and preparations (e.g., injection solutions, eye drops). The work of microbiologists, surgeons, and personnel involved in the manufacture and application of medicinal products is carried out using aseptic techniques. Creating aseptic conditions involves the disinfection of premises as well as the sterilization of equipment, instruments, and Materials.

Antisepsis denotes the application of chemical substances (antiseptics) that kill or inhibit microbes present in contact with a macroorganism.

Sterilization is The process of completely destroying or removing all viable forms of microorganisms from an object. Pharmaceutical sterilization requires ensuring a high sterility assurance level (SAL). The most widely adopted standard is the guarantee that, following the sterilization of a drug batch comprising 10⁶ units, the number of non-sterile units will be equal to or less than 1—that is, the probability of non-sterility is 10^-6 while preserving the biological Properties of the product.

The selection of an industrial sterilization method is guided by specific criteria.

1) The resistance of the object to the sterilizing treatment (thermal, radiation, or light stability) is taken into account. Following sterilization, a reduction in the biological activity of the product by more than 1-2% compared to its initial level is unacceptable.

2) The effectiveness of the treatment against various microorganisms or the efficiency of their removal from the object of sterilization is considered.

3) The chosen method must provide maximum safety assurance for operators and communities residing near the manufacturing facility (which is particularly critical when using radiation sterilization units).

4) Performing sterilization requires appropriate technological equipment (autoclaves, dry-heat sterilizers, gas sterilizers, etc.).

5) The selected method must be economically viable.

In industrial practice, two groups of sterilization Methods are employed, based on either the destruction or the removal of microorganisms. Thermal, chemical, and radiation sterilization are used to destroy microorganisms present in an object. Conversely, microorganisms are removed from objects via Membrane filtration.

24.2.1 Thermal sterilization

The objects of sterilization include equipment, piping, fittings, nutrient media, additives, finished dosage forms (injection and infusion solutions of thermostable substances), primary packaging materials for sterile products, sterilizing filtration units, and workwear.

Heat transfer agents may include pressurized steam, flowing steam, and dry hot air. Direct (live) steam is fed straight into the object (apparatus), whereas indirect steam is supplied to the sterilizer jacket. The sterilization of thermostable solutions is carried out in sealed sterile vials or ampoules using autoclaves at an overpressure of 0.11 MPa, which corresponds to a temperature of 121°С for 8-15 minutes, depending on the volume of the preparation. The efficacy of autoclaving is 10^-6. Sterilizing filtration units are sterilized for 45 minutes at 121°С, and workwear is treated at the same temperature for 40-60 minutes.

Some heat-stable injection preparations are sterilized with flowing steam at 100°С for 30 min. Primary packaging materials for sterile preparations (ampoules, vials) can be sterilized with dry hot air at 180°С for 2 hours. The efficiency of this sterilization method is 10¹². Extended sterilization times adversely affect the quality characteristics of Glass; therefore, alternative Processing regimes are used for primary packaging materials: 300°С for 20 min or 350°С for 2 min. Sterilization is carried out in a stream of sterile air, free from mechanical particles, with simultaneous depyrogenation of the processed items taking place during sterilization.

24.2.2 Gas and Chemical Solution Sterilization

The objects of sterilization are thermolabile medical devices made of rubber and polymeric materials, therapeutic films, lenses, rubber nipples, and eye-drop tubes. The primary active ingredient is ethylene oxide. This compound is used in a mixture with explosion-proof gases, such as carbon dioxide or methyl bromide, to improve gas Circulation within the object. The sterilization efficiency is 10^-2, and the processing is carried out in hermetically sealed, autoclave-type apparatuses connected to a gas cylinder.

Antimicrobial activity depends on the biocide concentration, treatment time, temperature, and humidity of the treatment environment. The optimal conditions are: gas concentration of 50-100 mg/L, exposure time of 1-6 h, temperature of 50-60°С, and humidity of 30-60%.

The widespread application of this method is hindered by the high toxicity of ethylene oxide to personnel and its ability to react with the Components of the object. Following sterilization, active or passive desorption is performed to remove residual ethylene oxide. In active desorption, the sterile products are purged with sterile air, whereas in passive desorption, they are left to stand for 20 days.

Formaldehyde is recommended for the sterilization (disinfection) of dialysis apparatuses. It is less hazardous than ethylene oxide, non-flammable, its leaks can be detected by odor, and the transportation of formaldehyde in aqueous solution form is relatively safe (requiring no gas cylinders).

24.2.3 Radiation and UV Sterilization

The objects of radiation sterilization include polymeric items such as infusion solution containers, Blood collection and transfusion sets, disposable syringes, polymeric Petri dishes, and bacteriological seals.

The efficiency of radiation sterilization is 10^-3. Processing is carried out in special continuous-action chambers, sterilizing in a γ-irradiation stream 2 times for 5 min each. The sterilizing dose is 25 — 30 kGy. The widespread adoption of this method is limited by the Direct and Indirect damaging effects of radiation on the object.

In industry, UV sterilization is used on a very limited scale, for example, in The production of certain vaccine preparations or for sterilizing polymeric microplates containing dry biochemical Reagents for the rapid identification of microorganisms. In pharmaceutical manufacturing, UV irradiation is used to reduce the microbial load in production facility air, combined with chemical treatments.

24.2.4 Sterilizing Filtration of Liquids

The objects include thermolabile soluble nutrient medium components and additives (40% glucose solution, ammonia solutions, phenylacetic acid solutions), thermolabile soluble drug substances (intermediates), thermolabile parenteral drugs, immunobiological preparations, organic Solvents, and disinfectant solutions. The sterilization efficiency is 10^-3.

It is mandatory to perform preliminary filtration through membranes with pore sizes of 5 µm and 0.5 µm, after which the solution is subjected to sterilizing filtration through a 0.22 µm membrane. Filters made of porous or ceramic materials can be used for pre-filtration. However, their significant drawbacks include the risk of filter material particles shedding into the filtrate, as well as the adsorption of certain substances (proteins) by the filter material. Microfiltration membranes removing particles sized 0.1-10 µm are used for sterilizing filtration. However, ultrafiltration membranes retaining particles sized 0.001-0.1 µm are used to remove viruses from thermolabile liquids. The membranes are made of various polymeric materials, such as Cellulose esters, polyamide, and polyethylene terephthalate film. For ease of use, they are supplied in the form of cartridges or discs.

To achieve effective sterilization, it is necessary to pre-check the membrane pore size, the integrity of the setup, and correctly select the filtration regime (operating duration, pressure, or vacuum).

Membrane pore size is evaluated by a microbiological method using Brevundimonas diminuta cells, which have a diameter of 0.3 µm (for filters with a 0.22 µm pore diameter). For filters with a pore diameter of 0.45 µm, the test Organism is Serratia marcescens, with a cell size not exceeding 0.5 µm. The suspension concentration is 10⁷ cells per 100 mL.

The integrity of the setup is checked using the bubble point test. The bubble point is the minimum air or gas pressure required to displace liquid from the filter surface. To prevent the uncontrolled proliferation of microorganisms on the filter and The Development of pyrogenicity in the injection solution, the time elapsed from THE START OF filtration to the recovery of the sterile solution should be minimized as much as possible. In accordance with GMP requirements, this time must not exceed 8 h.

The initial bioburden of solutions supplied for sterilizing filtration must be minimal, not exceeding 100 cells per 1 mL of solution. As the concentration increases, so does the likelihood that small-sized microorganisms with convoluted shapes or lacking a rigid Cell wall will pass into the filtrate.

24.3 Monitoring the Efficiency of Sterilization Equipment

Several groups of methods are used to monitor compliance with the selected sterilization regime. Technical control methods involve periodic checks of pressure gauge, thermometer, thermocouple, and dosimeter readings. Such monitoring is performed by the enterprise's metrological services.

Chemical control methods are based on The Use of various substances that change their color or physical state during sterilization, specifically those having a defined melting point. Sealed ampoules containing a powder pre-mixed with a dye are placed in the sterilization chamber. Upon reaching a certain temperature in the chamber, the powder melts, forming a uniformly colored melt (Table 54).

Class="center">Table 54. Melting points of chemical indicator substances.

Certain chemical indicators change color upon exposure to ethylene oxide or a specific dose of ionizing radiation. There are indicators that respond to sterilization temperature and time, indicators that register the completeness of air removal from the autoclave, and others.

The most comprehensive information on compliance with the sterilization regime is provided by biological control methods. The indicator is the death of test microorganisms used as controls, with the test culture required to be resistant to the sterilizing agent (Table 55).

Table 55. Biological indicators recommended by EP 2002 for monitoring sterilization processes

Note: * — at a temperature of 54 °C, relative humidity of 60%, and EtOx concentration of 600 mg/ml.

A biological indicator for monitoring autoclave operation is a suspension of Bacillus stearothermophilus spores (10⁶/ml) in a liquid nutrient medium (meat-peptone broth) supplemented with bromocresol purple indicator. The ampoule is placed inside the autoclave along with the items to be sterilized. Following sterilization, the biological indicator is incubated in a thermostat at 55°C. If sterilization is ineffective, surviving spores germinate, causing a color change in the pH indicator of the medium, while cell proliferation turns the medium turbid. A drawback of using biological indicators compared to chemical ones is the retrospective Nature of the results. To overcome this limitation, a system has been developed based on the Determination of the enzyme α-glucosidase, which indicates spore viability and is measured by The conversion of a non-fluorescent substrate into a fluorescent product within 1 hour. This system is recommended for monitoring pressurized steam sterilization.

General Requirements for organizing the monitoring of sterilization equipment performance:

1) monitoring must be continuous due to potential operational defects in sterilization equipment;

2) monitoring devices must be placed in locations least favorable for the sterilizing agent;

3) when using biological indicators, strict precautionary measures must be observed to prevent indicator microorganisms from entering the production environment.

24.4 Sterilization in Pharmacies

In accordance with Order No. 309 of the Ministry of Health of the Russian Federation dated October 21, 1997, "On the Approval of Instructions for the Sanitary Regimen of Pharmacy Organizations (Pharmacies)," the following sterilization regimes and methods for specific objects are approved:

✵ steam method (Table 56);

✵ dry-heat method (Table 57);

✵ chemical method (Table 58).

Table 56. Steam method (saturated steam under elevated pressure).

* The temperature regime of steam sterilization is monitored using a maximum thermometer with a scale up to 150°C or thermocouples. A mixture of benzoic acid and fuchsin (10:1), with a melting point of 121°C, is used as a chemical thermal test.

Table 57. Dry-heat sterilization method (dry hot air)

Note: Pharmacy glassware is removed after the temperature in the sterilizer drops to 60–70°C and is immediately sealed with sterile stoppers.

* Dry-heat sterilization is monitored using indicator paper (based on thermochromic ink No. 6), which changes color at 160°C, or by using chemical thermal tests such as sucrose or thiourea (melting point 180°C) and hydroquinone (melting point 170°C).

Table 58. Chemical sterilization method

*Technology, quality control, and shelf life of the 6% hydrogen peroxide solution prepared in pharmacies (Methodological Guidelines approved on July 18, 1996).

24.5 Industrial Disinfection

Disinfection refers to a set of measures aimed at eliminating microorganisms on environmental objects using mechanical, physical, and chemical agents and treatments. In medicine, disinfection is defined as the process of destroying predominantly pathogenic Microorganisms in the environment in order to interrupt the transmission of an infectious agent from a sick person to a healthy one. In industrial settings, it is also important to eliminate saprotrophic microorganisms, with the number of their species increasing in accordance with regulatory requirements for the microbial purity of production facilities.

The objects of industrial disinfection include production room air, surface areas, equipment, and utility lines. Industrial antisepsis can be considered a specific case of disinfection. It is a distinct field of disinfection that involves the use of chemical agents with non-specific antimicrobial action (antiseptics) to destroy or inhibit the proliferation of microorganisms on the Skin surface (less frequently, mucous membranes) of production personnel.

In medicine, The Essence of antiseptic measures lies in the USE OF ANTIMICROBIAL agents for treating wounds, cavities, the surgical field, and personnel's hands to combat infectious disease pathogens. Disinfection in chemical and pharmaceutical manufacturing is carried out during preparations for operations to achieve the required level of microbial purity in rooms (when establishing specific cleanroom classes), equipment, and the finished product.

Antiseptics are used as part of a comprehensive set of Sanitary and hygienic measures during staff preparation for work and throughout the technological process (in aseptic production facilities).

24.6 METHODS OF DISINFECTION

Mechanical, physical, and chemical disinfection methods are distinguished. During mechanical disinfection, microorganisms are merely removed from an object rather than destroyed, which occurs during wet cleaning, laundering, and ventilation.

Physical methods include ultraviolet (UV) treatment. Arc lamps, low-pressure gas-discharge lamps, and DB-15, DB-30, and DB-60 germicidal lamps are used (depending on power) with an emission wavelength of 253.7 nm. The service life of a lamp is 1,500–2,000 hours. By the end of this period, the power and, consequently, the effectiveness against microorganisms decrease by 50% from the initial level. Direct-action lamps are used only in the absence of personnel, whereas scattered-light (shielded) lamps can be used during ongoing operations. Shielded lamps are placed no lower than 2 m from the floor level. The destruction of microorganisms occurs in the upper air layers, while the lower layers are disinfected through convection. Special air recirculation devices enhance treatment efficiency. The indoor air stream is passed through a chamber equipped with UV lamps and returned to the room after treatment. Special high-power lamps allow disinfection via the flash method (for example, treating 30 m³ of the air phase takes only 2 minutes, and 60 m³ takes 5 minutes).

Limitations of UV treatment include the toxic effects on personnel from generated ozone (O₃) and nitrogen oxides (NO), as well as adverse effects on the retina of the eyes.

Additionally, thermal disinfection methods are employed (boiling, treatment with steam or dry hot air).

Chemical disinfection involves treating an object with chemical disinfectant agents through washing, wiping, immersion, or spraying (aerosol treatment). Aerosol treatment helps reduce disinfectant consumption and its corrosive impact on the treated surface, while also allowing hard-to-reach areas to be processed. Treatment efficiency increases as the size of the aerosol particles decreases. The optimal particle size is 1–10 µm, which is comparable to the size of microbial cells.

Requirements for chemical disinfectants and antiseptics:

1). Good solubility or The ability to mix with water to form stable solutions.

2). Low toxicity and the absence of irritating effects on the skin and mucous membranes of personnel.

3). A broad spectrum of antimicrobial activity manifested in the shortest possible time.

4). The ability to thoroughly wet objects without causing corrosive or other destructive effects.

5). Stability during storage.

6). Official authorization for use as a disinfectant in the chemical and pharmaceutical industry.

The limitations on using disinfectants in the chemical and pharmaceutical industry are determined by their safety for personnel and the availability of methods for removing traces of these substances from the object.

24.7 Main Groups of Disinfectants and Purposes of Their Use

Oxidizing Agents

Solutions of H₂O₂ are the most widely used due to their effective action against both vegetative cells and spores. Solutions are unstable at low concentrations. Heating to 40–50°C increases treatment efficiency. H₂O₂ is used for treating rooms and corrosion-resistant equipment made of glass and polymeric materials at a concentration of 3–6% combined with detergents. A 6% H₂O₂ solution can be sprayed as an aerosol for room air decontamination.

Peracetic acid in a 0.3–0.5% solution is used for treating rooms and corrosion-resistant equipment at a rate of 300 ml/m ^2. All work involving the preparation of working solutions and disinfection must be carried out wearing protective clothing, gloves, and a respirator.

Halogen-Containing Substances

For disinfection purposes, bleaching powder (chloride of lime) and chloramine B are used as 5–10% solutions for treating corrosion-resistant equipment, and at a 0.2% concentration for treating containers and water-for-injection pipelines.

Surfactants (Surface-Active Agents)

Cationic surfactants are the most widely used, encompassing the entire group of quaternary ammonium compounds (QACs): benzalkonium chloride, cetylpyridinium chloride, degmin, dimicid, catamine AB, etc. Catamine AB is used as a 0.5–1% solution at a consumption rate of 0.5 L per 1 m² of surface. After a 30-minute exposure time, the substance is removed by rinsing the surface with water. It is used for disinfecting equipment, including non-corrosion-resistant equipment. Catapol, a polymeric complex of catamine AB, exhibits lower toxicity compared to the parent substance and is recommended for air disinfection in aerosol form, as well as for treating hands and equipment surfaces.

Surfactants are ineffective against bacillary spores; however, when mixed with H₂O₂, they exhibit sporicidal activity (e.g., PVK, a solution of catamine AB containing H₂O₂, grylen, peramin — mixtures of QACs with H₂O₂).

Surface activity is exhibited by detergents, which also possess antimicrobial properties. In the chemical and pharmaceutical industry, products such as Progress, Sulfonol, and Afol are widely used.

Biguanides, such as chlorhexidine bigluconate, are used in 0.1–0.2% solutions at a rate of 200 ml per 1 m² for the disinfection of premises and equipment, as well as for air aerosol treatment. Chlorhexidine bigluconate is available as a 20% solution (Hibitane), and under the trade names Plivasept (a 5% solution with added surfactants) and Plivasept tincture (a 5% solution of chlorhexidine bigluconate mixed with 80° ethanol).

Aldehydes

Glutaraldehyde is used for disinfection as a 2% solution mixed with an activator (Glutaral preparation), as well as in combination with glyoxal and quaternary ammonium compounds (QACs) (Lysoformin 3000). Formaldehyde is a highly reactive substance; due to its pronounced irritant effect on the skin and mucous membranes, it is extremely rarely used for disinfection purposes.

The following agents are used for personnel hand hygiene:

Degmin — a quaternary ammonium compound (QAC) of hexamethylenimine and high-molecular-weight alcohols, formulated as a 1% aqueous solution.

Solution S-4 — a mixture of H₂O₂ and formic acid solutions. Solution S-4 is used at a mass fraction of 2.4%.

Ethyl alcohol as a 76% solution.

24.8 Microbial Contamination of Antiseptic and Disinfectant Solutions

Almost all antimicrobial agents used for disinfection (antiseptics) can harbor contaminating microbes, with pseudomonads being the primary culprits.

Microorganisms enter solutions during their preparation, storage, and use. Sources include raw starting powders, concentrated anhydrous liquids, water and other solvents, stabilizers, other excipients, and storage containers.

Secondary contamination can occur As a result of improper storage and handling practices, such as open storage, withdrawing solutions from containers using contaminated equipment, and the like.

The consequence of using contaminated disinfectant and antiseptic solutions is the risk of finished product contamination and the spread of multi-drug resistant microbial strains. Therefore, strict adherence to the rules of disinfectant solution preparation in accordance with GMP requirements is essential:

1) use purified water for the Preparation of Solutions;

2) use pre-washed glassware and equipment;

3) disinfectant solutions must be stored for a limited (strictly defined) period of time;

4) topping up partially used containers with freshly prepared solution is not permitted;

5) periodic rotation of disinfectants is required to prevent the selection of resistant strains;

6) in the manufacture of sterile finished pharmaceutical products (FPPS), Antiseptics and disinfectants must be sterile. The solutions are sterilized by membrane filtration through 0.45 µm pore size filters.

24.9 Disinfection in Pharmacies

In accordance with Order No. 309 of the Ministry of Health of the Russian Federation "On approval of the instruction on the sanitary regime of pharmacy organizations (pharmacies)," thermal (Table 59) and chemical (Table 60) methods and agents have been approved for the disinfection of various objects.

Table 59. Thermal agents and disinfection regimens

Table 60. Chemical agents and disinfection regimens

** After completing work, wash hands with warm water and apply emollient creams.

Conclusion

Asepsis is a set of measures aimed at preventing the Introduction of microbes onto any object. Aseptic conditions are established through disinfection and sterilization.

Antisepsis is the destruction or inhibition of the growth of microbes in contact with the human body using chemical substances known as antiseptics.

Sterilization is the process of completely destroying or removing all viable microorganisms from an object.

The MAIN TYPES OF sterilization include thermal (dry heat or pressurized steam), chemical (using gases or biocidal solutions), radiation (y-irradiation), and membrane filtration.

Sterilization control is carried out using chemical and biological methods.

Disinfection is a set of measures aimed at destroying fungi on (or in) environmental objects using mechanical, physical, and chemical means.

The main groups of disinfectants include oxidizing agents (Н2О2, etc.), halogens (bleaching powder, chloramine B, etc.), surfactants, aldehydes, and alcohols.

Improper preparation and storage of disinfectant solutions may result in contamination, for example, with Pseudomonas species.