Page 77 - MNU-PM502- Pharmaeutical Microbiology Theoritical Book

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

Viscous oils are diluted first with suitable sterile
diluent.
Ointments and o dilute with a suitable diluent that is sterile and
creams has no antimicrobial activity.
o Add a suitable emulsifying agent to the media in
case of using direct inoculation method.

antimicrobial Inactivation of antimicrobial agents can be carried out
agents either by
• Dilution of the preparation to less than MIC

• Addition of inactivating agent
➢ e.g. inactivation of sodium benzyl penicillin by
penicillinase solution.
➢ Inactivation of sulphathiazole by addition of
0.005% para-amino benzoic acid.

Pyrogen testing

• Bacterial endotoxin, lipopolysaccharide (LPS), is a fever-

producing by-product of Gram-negative bacteria commonly known as
pyrogen.

• Bacterial cells may be pyrogenic even when they are dead and so a solution or

material that passes a test for sterility will not necessarily pass a pyrogen test

1- Biological test (Rabbit pyrogen test)

Using group of 3 rabbits (healthy, mature, same size and sex)

Procedure

- Withheld food in the day of experiment.

- Record the initial temperature of the rabbits.

- Any rabbit exhibiting temperature more than
39 should be excluded.

- Inject the sample into the ear vein of each rabbit.

- Measure the temperature after 30 min, 1, 2, 3 hrs.

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