GAMMA RAYS STERILIZATION

04/11/2023Smt.Kashibai Navale College Of

Pharmacy,Kondhawa,pune. 2

GAMMA RAYS STERILIZATION

Presented By Guided By

Sagar G. Lingot Dr. G. V. Patil mam

M. PHARM (SEM– I) H.O.D

DEPT. OF PHARMACEUTICS

DEPT. OF PHARMACEUTICS

History Definition Method of sterilization Source of gamma rays General aspects of gamma rays Effect of gamma rays: on living organism on human tissue grafts on food on medical devices Sterilization dose Conclusion Advantage and disadvantage Application

CONTENT

STERIS has provided gamma sterilization services since 1972. However, the history of gamma irradiation dates back as far as 1895.

Gamma Radiation: Timeline of Events 1895 W.C. Roentgen discovers X-rays 1896 A.H. Becquerel observes radiation emitted

form uranium 1897   J. Thompson discovers the electron 1898  Marie & Pierre Curie discover several

radioactive elements and first use the terms “radioactive” and “radio activity”

1963 The first gamma irradiator in the US was installed in New Jersey for the processing of medical device 

HISTORY

Sterilization is defined as any process that effectively kills or eliminates almost all microorganisms like fungi, bacteria, viruses, spore forms.

There are many different sterilization methods depending on the purpose of the sterilization and the material that will be sterilized.

Definition

A) Physical Methods 1) Dry heat sterilization 2) Moist heat sterilization 3) Radiation sterilization a) use of UV rays b) Ionizing radiation ( X-rays and Gamma rays)

B) Chemical Methods 1) Sterilization by heating with bactericide 2) Gaseous sterilization

c) Mechanical Methods 1) Ceramic filter 2) seitz filter 3) sintered glass filter 4) sintered metal filter 5) Membrane filter

Methods of Sterilization

GAMMA RAYSSTERILIZATION

Gamma radiation sterilization are mainly used for the sterilization of pharmaceuticals. Gamma radiation delivers a certain dose that can take time for a period of time from minutes to hours depending on the thickness and the volume of the product.

gamma sterilization requires time, contact and temperature. The effectiveness of any method of sterilization is also dependent upon four other factors like the type of microorganism present. Some microorganisms are very difficult to kill. Others die easily the number of microorganisms present.

Introduction

Gamma rays are formed with the self disintegration of Cobalt-60 (60Co) or Cesium-137 (137Cs) sources. Among thousands of gamma emitters only 137Cs and 60Co are indicated for radiation processing.

The energy of gamma rays, as electromagnetic quantum waves, is similar to light, but with higher photon energy and shorter wavelength. The 60Co radionuclide can be produced in a nuclear power reactor by the irradiation of 59Co

(metal), with fast neutrons. The radioactive isotope is formed by neutron capture as showed equation (Laughlin, 1989).

27Co59+ 0n1→ 27Co60

Source of gamma rays

Dynamitron Processing Method for the production of electron, which is useful for gamma radiation

Production of electron of radiation

Gamma irradiation is a physical means of decontamination, because it kills bacteria by breaking down bacterial DNA, inhibiting bacterial division. Energy of gamma rays passes through hive equipment, disrupting the pathogens that cause contamination. These photon-induced changes at the molecular level cause the death of contaminating organisms or render such organisms incapable of reproduction.

The gamma irradiation process does not create residuals or impart radioactivity in the processed hive equipment. Complete penetration can be achieved depending on the thickness of the material. It supplies energy saving and it needs no chemical or heat dependence.

Mechanism of Gamma rays sterilization

The most important physiological and environmental parameters are temperature, moisture content and oxygen concentration.

Radiolytic products of water are mainly formed by indirect action on water molecules yielding radicals OH. , e- aq and H.. The action of the hydroxyl radical (OH.) must be responsible for an important part of the indirect effects. Drying or freezing of living organisms can reduce these indirect effects. If we consider pure water, each 100 eV of energy absorbed will generate: 2.7 radicals OH., 2.6 e- aq, 0.6 radicals H., 0.45 H2 molecules and 0.7 molecules H2O2.

Applications

Gamma sterilization of human tissue grafts

Connective tissue allograft , such as bone, cartilage, tendons, ligaments, Dura mater, skin , amnion, pericardium, heart valves and corneas, are widely used for reconstructive surgery in many clinical disciplines, including orthopedics , Traumatology, neurosurgery,

cardio surgery , plastic surgery, laryngology and ophthalmology.

Food sterilization by gamma irradiation is the process of exposing food to ionizing radiation to destroy microorganisms, bacteria, viruses, or insects that might be present in the food.

Irradiated food does not become radioactive, but in some cases there may be some chemical changes.

Gamma sterilization of food

Type of food Effect of Radiation

Meat, poultry Destroys pathogenic fish organisms, such asSalmonella, Campylobacter and Trichinae

Perishable foods Delays spoilage; retards mold growth;reduces number of microorganisms

Grain, fruit Controls insect vegetables, infestationdehydrated fruit, spices and seasonings andreduces rehydration time

Onions, carrots, potatoes, garlic, ginger Inhibits sprouting

Bananas, mangos, papayas, guavas, othernon-citrus fruits

Delays ripening avocados, natural juices

Gamma sterilization of medical devices

Ionizing radiation not only kills microorganisms but also affects material properties. Medical devices are made of many different materials, some of which are metals, but most are non-metals, such as formed polymers, composite structures and even ceramics. Radiation itself does not directly affect metals since sterilization energies are safely below any activation thresholds.

Metals, such as those used in orthopedic implants, are virtually unchanged by the radiation sterilization process.

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Survival fraction of the microorganisms is reversely proportional with the absorbed dose. Doses for sterilization should be chosen according to the initial bio burden, sterility assurance level (SAL) and the radio sensitivity of microorganisms. A sterility assurance level (SAL) is derived mathematically and it defines the probability of a viable microorganism being present on an individual product unit after sterilization.

SAL is normally expressed as 10−n. SAL is generally set at the level of 10−6 microorganisms/ml or g for the inject able pharmaceuticals, ophthalmic ointment and ophthalmic drops and is 10-3 for some products like gloves that are used in the aseptic conditions.

Sterilization dose

Advantage gamma rays have a high penetration power so

materials can be sterilized after filling them in the final container

The method is suitable for all types of material such as dry, moist and frozen

The method is reliable and can be accurately controlled

Some bacterial and viral vaccines can be sterilized because the exposure time is very short

Disadvantage The radiation are harmful to workers It produce undesirable changes in many medicament

such as colour , solubility and texture of the product

Advantage and disadvantage

The method is mainly used for sterilization of plastic syringes, hypodermic needles, scalpels, surgical blades and adhesive dressings.

It is also used for sterilization of bone and tissue transplant, plastic tubing , catheteres and sutures.

It is used for sterilization of thermolabile medicaments.

Application

Remington, volume I, page no. 772 Sterilization by gamma radiation by silva aquino, Brazil The study of the sterilization efffect of

gamma ray irradiation of immobilized collagen polpropylene nonwoven fabric surfaces

Yung-chang tyan, chung univercity International organization of standardization

(1995),volume second

References