Radiation Sterilization in Pharmaceutical Industry

Radiation is a non-thermal sterilization method that destroys microorganisms in a product with gamma radiation, beta particles (electron beam), or ultraviolet light. Other than sterile filtration, radiation is the only other sterilization method that doesn’t rely on elevated temperature in order to sterilize. Radiation is an excellent alternative for products that cannot be sterilized with heat or chemicals.

Non-ionizing radiation sterilization

Ultraviolet light irradiation (UV, from a germicidal lamp) is useful for sterilization of surfaces and some transparent objects. Many objects that are transparent to visible light absorb UV. UV irradiation is routinely used to sterilize the interiors of biological safety cabinets between uses, but is ineffective in shaded areas, including areas under dirt (which may become polymerized after prolonged irradiation, so that it is very difficult to remove).[58] It also damages some plastics, such as polystyrene foam if exposed for
prolonged periods of time.

Ionizing radiation sterilization

Ionizing radiation is a type of energy released by atoms that travels in the form of electromagnetic waves (gamma or X-rays) or particles (neutrons, beta or alpha). The spontaneous disintegration of atoms is called radioactivity, and the excess energy emitted is a form of ionizing radiation.

Gamma radiation is very penetrating, and is commonly used for sterilization of disposable medical equipment, such as syringes, needles, cannulas and IV sets, and food

Advantages

1. Terminal Processing: Due to the penetration depth of ionizing radiation, products can be processed in their fully sealed, final packaging. This limits risk of contamination following sterilization.

2. Cold Method/Temperature Independence: Temperature increases during treatment are minimal. Furthermore, radiation sterilization has no heat.

3. No residue: Radiation leaves no residue on the sterilized product.

4. Chemical Independence: No volatile or toxic chemicals are needed.

5. Flexibility: Radiation can sterilize products of any phase (gaseous, liquid or solid materials),

6. Time efficiency: sterilization can be completed within seconds to minutes.

Disadvantages

1. There is some risk involved since exposure to radiation may be harmful to workers

2. It can produce undesirable changes in medicine such as color, solubility and texture of the product.

3. It can actually damage the material it’s meant to sterilize.

Read also:

• Moist Heat or Steam Sterilization Working Principle
• Difference between Sterilization and Depyrogenation

Resource Person: Ch/Ahmed Mahmoud