Pyrogen and Particulate Matter Flashcards
When are compounded sterile preparations (CSPs) most hazardous to patients?
Contaminated CSPs are potentially most hazardous to patients when administered into body cavities, central nervous and vascular systems, eyes, and joints, and when used as
baths for live organs and tissues.
What are parenteral preparations? How are they administrated?
Sterile preparations intended for administration by injection, infusion or implantation into the human or animal body
What does the word pyrogen mean and what happens when a pyrogenic reaction occurs?
Pyro = pyrexia
Gen = agent
Substance/chemical that increases body temperature (induced fever). It is NOT an ORGANISM.
What are the 4 properties that pyrogens share?
- Water soluble
- Macromolecules
- Thermostable (meaning that it needs a high temperature to be inactivated)
- Non-volatile in steam (when steam is produced, it will be free of pyrogen) –> property exploited in the preparation of both forms of Water for Injections B.P.)
What is the main pyrogen produced by microbes? What properties does this pyrogen have for it to be the most common cause of toxic reactions?
Bacterial endotoxin (gram-negative)
> These endotoxins are lipopolysaccharides (LPS). LPS forms part of the cell wall in gram-negative bacteria
- Lipo = Hydrophobic properties which make it stick to the wall of a container
- Polysaccharide = Water soluble
What does the absence of bacterial endotoxins in a product mean?
Absence of pyrogenic components
What are the differences between exotoxins and endotoxins? Explain how they leave their structues.
- Exotoxins: Produce inside mostly gram-positive bacteria. Release following lysis into surrounding medium
- Endotoxins: Part of the outer portion of the cell wall (LPS) of gram-negative bacteria. Released when bacteria die and the cell wall breaks apart.
What response does the pyrogen (pyrogenic response) induce in a human/animal?
(clue: 4 steps)
- Macrophage ingests gram-negative bacterium
- Bacterium is broken down, releasing endotoxins that induce the macrophage to produce interleukin-1 (IL-1)
- IL-1 is released by the macrophage into the bloodstream, it then travels to the hypothalamus of the brain
- IL-1 induces the hypothalamus to produce prostaglandins which reset the body’s temperature to a higher temperature. PRODUCES FEVER
Give 4 examples of sources of pyrogens and explain how they may cause pyrogenic activity.
- Aqueous system that is allowed to stand
- Distilled water contaminated with airborne bacteria/ entrainment by a poor distillation procedure
- Apparatus and containers
- Medicaments such as glucose, sodium citrate, and sodium chloride
Why must any type of container be fitted with baffles (covers)?
To prevent the entrainment of droplets from the boiling water into the distillate
Provide THREE methods for the prevention of pyrogens. Explain why they work
Safeguards against the contamination of the distillate by airborne bacteria must be exercised
- Distilled water must be covered during its collection, and must be used as soon as possible after distillation to prevent multiplication of bacteria
Solutions should be filtered, packed, sealed and sterilized as rapidly as possible
- Will reduce the possibility of bacterial multiplication and as a result, lessen the chances for the development of pyrogens
Choice of parenteral medications and preparation of apparatus (compounding and packaging) –> properly designed and operated still, fitted with baffles
- Prevent entrainment of droplets from boiling water into the distillate
Provide two methods for the removal of pyrogens
It is better to prevent the formation of pyrogens than to attempt their removal.
- Dry heat at 230ºC or higher for a period of time. (thermostable apparatus and medicaments)
- Adsorption on activated asbestos or charcoal (may adsorb active ingredients) or by ultrafiltration. (Thermolabile medicaments –> destroyed by heat)
Which products are tested for pyrogens?
- Injectable drugs and medical devices which will have contact with blood or spinal fluid
- Includes raw materials, water and in process monitoring
How is testing for pyrogens done?
Clue: 3 methods
- Rabbit pyrogen test
- Monocyte-activation test (MAT) –> a replacement for the rabbit pyrogen test
- LAL test
What is the process for the rabbit pyrogen test?
- Substance being tested is injected in rabbits ear
- Measure the rabbit rectal temperature, the temperature depends on how many rabbits are being tested (see attached image)
Main test: volume, route and time (initial temperature, max temperature response; summed response)
What is the process for the Monocyte-activation test (test for pyrogen)?
The monocyte-activation test (MAT) is used to detect substances that activate monocytic cells to release mediators such as proinflammatory cytokines
- E.g. alpha TNF, interleukin-1 beta, and interleukin-6 (IL-6).
- These cytokines have a role in fever pathogenesis
- Consequently, the MAT will detect the presence of pyrogens in the test sample (detection of IL-6 with ELISA test)
- The MAT is suitable after a product-specific validation –> as a replacement for the rabbit pyrogen test
What is the process for the LAL test (test for pyrogen)? What makes this test unique for testing pyrogens?
THIS METHOD ONLY DETECTS ENDOTOXINS FROM GRAM-NEGATIVE BACTERIA
- By using amebocyte lysate (crab blood). Its blue due to copper.
- This is an in vitro procedure that is more sensitive than the rabbit rectal temperature method
What’s the difference in water for injections and sterilized water for injections for parenteral production?
Water for injections: used as a vehicle/ingredient to prepare a parenteral product, free from any added substances
Sterilized for water injections: a product that is packed in a container, free from any added substances
Bacterial endotoxins for both
- BP: less than 0.25 IU/mL
- USP: less than 0.25 USP endotxin unit per mL
How is bacteriostatic water for injection prepared? What is the USP requirement for endotoxin unit per mL
Prepared from water for injection that is sterilized and suitably packaged –> containing one or more suitable antimicrobial agents
- The antimicrobial agent is benzyl alcohol most of the time –> could be harmful to infants and may interact with other ingredients
- Less than 0.5 USP Endotoxin Unit per mL
What is the sterilization process for the following parenteral packaging materials;
A) Glass
B) Rubber
C) Plastic
A)
- Dry heat, steam or ethylene oxide sterilisation
- Discoloured by gamma-irradiation
B)
- Steam and ethylene oxide sterilisation subjected to adequate aeration to remove residues
- Physicochemical changes may occur with irradiation
- Generally will not withstand dry heat
C)
- Only a few plastics will withstand dry heat
What is particulate matters in injections and infusions?
Particulate contamination of injections and infusions consists of extraneous (external), mobile undissolved particles, other than gas bubbles, unintentionally present in the solutions
For Particulate Contamination;
A) Give examples of intrinsic contamination (materials used to make product)
B) Give examples of extrinsic contamination
A)
- raw materials
- chemicals
- solvent impurities
- packaging components
- equipment
- filter fibers
B)
- environmental contaminants
- operators –> skin scales shedding
What are the potential hazards for particulate matters in parenteral preparations?
Clue: 3 reasons
- Physical occlusion
> The smallest capillary blood vessels have a diameter of 5-10 µm. Thus, all particles having a size equal to or greater than 7 µm can can occlude a blood capillary
- Inflammatory reactions
- Antigenic responses
How to observe particular contamination?
By using an apparatus that consists of;
A) Matt Black Panel
B) Non-glare white panel
C) Adjustable lamp holder
- Gently swirl or invert a container, ensuring that air bubbles are not observed for five seconds in front of the white panel. Repeat the procedure in front of the black panel.
OR
- Use polarised light for the detection of particulate matter in transparent liquids contained in ampoules, vials, and bottles
- To operate, hold the container between the light panel and the polarising screen, shake and the particles will show as bright specks against a dark background
