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STERILIZATION (PowerPoint download)

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					STERILIZATION
             STERILIZATION


 STERILITY: Absence of life or absolute
  freedom from biological contamination.
 STERILIZATION: Inactivation or
  elimination of all viable organism and their
  spores.
                    STERILIZATION

   DISINFECTANT: Substance used on non-living
    objects to render them non-infectious; kills
    vegetative bacteria, fungi, viruses but Not Spores.
       e.g. Formaldehyde
               STERILIZATION


 BACTERICIDE (GERMICIDE): Substance that
  kills vegetative bacteria and some spores
 BACTERIOSTAT: Substance which stops growth
  and multiplication of bacteria but does not
  necessarily kill them. Growth
  usually resumes when bacteriostat
  is removed.
                   STERILIZATION


   ANTISEPTIC: Substance used to prevent
    multiplication of microorganism when
    applied to living systems. An antiseptic
    is bacteriostatic in action but not
    necessarily bacteriocidal.
            STERILIZATION


 VEGETATIVE CELL: Bacterial cell
  capable of multiplication (as oppose to
  spore form which cannot multiply). Less
  resistant than the spore form.
 SPORE: Body which some species of
  bacteria form within their cells which is
  considerably more resistant than the
  vegetative cell.
                STERILIZATION

 Methods:
 1. Steam Sterilization
 2. Dry heat sterilization
 3. Filtration
 4. Gas sterilization
 5. Irradiation
 NOTE: End products must pass sterility tests.
                      STERILIZATION
DRY HEAT STERILIZATION:
 Equipment: Oven
 Method:
 Dry heat sterilization is carried out at 160 deg C. to 170
  deg C. for 2 to 4 hrs.
 Application:
 Glassware
 Fixed oils
 Thermostable powders
                    STERILIZATION


   Advantages & Disadvantages:
    Sterilization by means of heat requires higher
    temperatures and longer exposures than
    sterilization by steam. Heat transfer is slow, small
    volumes of oil and thin layers of powder should
    be used.
               STERILIZATION

STEAM STERILIZATION:
Equipment: Autoclave
Method:
  In the presence of moisture, microorganisms
 are destroyed at a lower temperature than in
 dry heat. This is the method of choice when
 product can withstand such treatment.
                  STERILIZATION


10 lb Pressure (115.5 deg. C)...30 minutes
15 lb Pressure (121.5 deg. C)...20 minutes
20 lb Pressure (126.5 deg. C)... 15 minutes
                  STERILIZATION


Application:
1. Solutions sealed in containers ampuls, vials
2. Bulk Solutions
3. Glassware
4. Surgical Dressing
5. Instruments
               STERILIZATION

 Advantages:
Rapid, Inexpensive, Effective, Large volumes
 Disadvantages:
1. Cannot use for oily preparation (oil base
  ointment)
2. Cannot use for moisture sensitive preparations
              STERILIZATION

FILTRATION:

 Physical removal of microorganisms by
 adsorption on the filter medium. Used for heat
 sensitive materials.
                STERILIZATION


BACTERIAL FILTRATION:
Equipment:
 1. Porcelain filters
 2. Siliceous earth filter
 3. Sintered glass filters
 4. Asbestos filters
 5. Membrane filters
                STERILIZATION
 Method: Direct filtration
1. Positive pressure
2. Negative pressure
Application:
Thermolabile solutions of low viscosity.
 Advantages & Disadvantages:
1. Depend on filter media
2. Thermolabile solutions can be sterilized.
            STERILIZATION
GASEOUS STERILIZATION
Equipment:
Special oven, for admission of gas and
  humidity & hermetic
Method:
Humidity of less than 20% RH
Ethylene Oxide
            STERILIZATION
Ethylene Oxide-Carbon dioxide
Pressure 30 psi
Temperature 20-55 deg. C
Application:
Thermolabile powder plastic\polymers
  ophthalmic prep. subcutaneous, vaginal
  inserts, plastic syringes, tubing sets
                 STERILIZATION


 Advantages & Disadvantages:
1. Explosive hazard
2. Toxic
3. Not appropriate for solutions
              STERILIZATION
RADIATION STERILIZATION
Equipment:
 Ultraviolet Lamp
 Ionization (Beta Rays, Gamma Rays, X-Rays)
Application:
 Thermolabile Drugs (Powdered)
                  STERILIZATION


 Disadvantages:
1. Highly specialized equipment required
2. Effect of irradiation on products and their
  containers.
               STERILIZATION
STERILITY TESTS
 (A) Microorganisms:
     USPXXll recommends the use of biological
  indicators.
1. For liquid preparations-add directly to the
  preparations.
2. For solid preparations or equipments- add the
  culture to strips of filter paper.
                  STERILIZATION


Different organisms for different methods of
 sterilization.
The organisms that are resistant to a particular
 sterilization method should be chosen as the
 marker organism
                     STERILIZATION

Sterilization Method      Marker organisms
Steam sterilization       Bacillus stearothermophyilus
Dry-heat sterilization    Bacillus subtilis
Ethylene oxide            Bacillus subtilis
sterilization
Ionizing radiation        Bacillus pumilus
sterilization
                  STERILIZATION
   (B) Pyrogen and Pyrogen Testing
    Pyrogens are fever producing organic
    substances arising from microbial contamination.
    The causative material is thought to be a
    Lipopolysaccharide from the outer cell wall
    of the bacteria.
    This is Thermostable
               STERILIZATION

TESTS:
1. RABBIT TESTS
a) Render the syringes, needles and glassware
  free from Pyrogens by heating at 250 deg. C
  for not less than 30 minutes.
b) Warm the product to be tested to 37 deg. ± 2
  deg. C.
c) Take three healthy rabbits
                 STERILIZATION

d) Inject into an ear vein of each of three rabbits
  10 ml of the product per kg body weight.
e) Record the temperature at 1,2,and 3 Hrs.
                   STERILIZATION
CASE I
Results:
(i) No rabbit shows an individual rise in temperature
  at 0.6 deg. C or more above its respective control temp.
(ii) Sum of the three individual maximum temp. rises does
   not exceed 1.4 deg. C.
Conclusion:
The material meets the USP requirements for the absence
   of Pyrogen.
                  STERILIZATION
CASE II
Results:
(i) If any rabbits show a temp. rise of 0.6 deg.C or
   more or
(ii) If sum of the temp. rises exceeds 1.4 deg. C
Conclusion:
Repeat the tests using five other rabbits.
                   STERILIZATION

Results:
(i) If not more than three of the eight rabbits show
   individual rises in temp. of 0.6 deg. C or more
(ii) If the sum of the eight temp. rises does not exceed 3.7
   deg.C
Conclusion:
The material meets the USP requirements for the
   absence of Pyrogens.
                  STERILIZATION


2) LAL TESTS:
  Limulus Amebocyte Lysate (LAL) Tests
  Extract from the blood cells of the Horse Shoe
  Crab (Limulus Polyphemus) contains an enzyme
  and protein that coagulates in the presence of low
  levels of Lipopolysaccharides.

				
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posted:2/22/2012
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