Sterilization is the process that eliminates, removes, kills, or deactivates all forms of life and other biological agents such as fungi, bacteria, viruses, spore forms, prions, unicellular eukaryotic organisms such as plasmodium, etc. Sterilization can be carried out through heat, chemicals, irradiation, high pressure, and filtration. In one sentence, sterilization is the process by which an article, surface, or medium is freed from all living organisms either in the vegetative or spore state.
Autoclaves: They are highly effective and inexpensive. Unsuitable for heat-sensitive objects.
Hot air ovens: They are inefficient compared to
autoclaves.
Ethylene oxide: It is suitable for heat-sensitive
items but leaves toxic residue on sterilized items.
Low-temperature steam and formaldehyde: They are
effective for instruments with cavities or tubular openings.
Sporicidal chemicals: They are often used as
disinfectants but can also sterilize instruments if used for prolonged periods.
Irradiation: Gamma rays and accelerated electrons are
excellent at sterilization.
Gas plasma: Many types of gases are used as a source
of plasma which are used for the inactivation of microorganisms.
Sterilization Process Principle:
• Thorough cleaning of instruments before sterilization.
• Contact of sterilizing agent with all surfaces of each
item for a specified period of time at a specified temperature.
• Regular service and maintenance of sterilizing equipment.
Need for sterilization:
• Microorganisms are capable of causing infection.
• They are responsible for contamination and infection.
Mechanism:
• Denaturation of protein
• Oxidation
• Filtration
• Interference with protein synthesis
• Disruption of cell membranes
• Interruption of DNA synthesis/repair
Pharmaceutical Importance of Sterilization:
• Moist heat sterilization is the most efficient biocidal
agent. In the pharmaceutical industry, it is used for Surgical dressings,
Sheets, Surgical and diagnostic equipment, Containers, Closures, Aqueous
injections, Ophthalmic preparations Irrigation fluids, etc.
• Dry heat sterilization is used for thermo-stable,
moisture-sensitive, or moisture-impermeable pharmaceutical and medicinal. These
include products like; Dry powdered drugs, Suspensions of drugs in non-aqueous
solvents, Oils, fats waxes, soft hard paraffin silicone, Oily injections,
implants, ophthalmic ointments, and ointment bases, etc.
• Gaseous sterilization is used for sterilizing thermolabile
substances like; hormones, proteins, various heat-sensitive drugs, etc.
• U.V. light is the most lethal component in ordinary
sunlight used in the sanitation of garments or utensils.
• Gamma-rays from Cobalt 60 are used to sterilize antibiotics,
hormones, sutures, plastic catheters, etc.
• Filtration sterilizations are used in the treatment of
heat-sensitive injections and ophthalmic solutions, biological products, air,
and other gases for supply to aseptic areas. They are also used in industry as
part of the venting systems on fermenters, centrifuges, autoclaves, and freeze
driers. Membrane filters are used for sterility testing.