Page 36 - MNU-PM502- Pharmaeutical Microbiology Theoritical Book

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

Mechanical methods

Filtration

a process used to disinfect or sterilize gases and heat-sensitive liquids
by physically removing microbes not killing

Mechanisms of filtration:

• sieving, adsorption and trapping within the matrix of

the filter.
• Filters essentially contain tiny spaces or holes which
exclusively allow the liquid to pass but are too small

to permit the passage of the small particles.

• These filters are made of different materials

Materials Name of the filter

Asbestos pad Seitz filter

Diatomaceous earth Berkefeld filter

Cellulose Membrane filter
Borosilicate glass fiber HEPA filter

Clay, mud Candle filter

1- Membrane filters
• The most common type of filters used for liquid sterilization

• Made of cellulose acetate, cellulose nitrate
• Porosities range from 0.1μm to 10μm

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