Methods for standardization of antibiotics microbom iogy important topic

1. MS.NISHA MANDLOI
METHODS FOR STANDARDIZATION
OF ANTIBIOTICS

2. METHODS FOR STANDARDIZATION OF
ANTIBIOTICS
Antibiotic is a medical preparation, containing sufficient
amount of chemical entity which is caused to produce
naturally (by a microorganism) or by artificially (semi-
synthetic way) and that possesses the inherent ability
to either destroy (bactericidal) or inhibit (bacteriostatic)
microorganisms in relatively dilute solutions.

3. METHODS FOR STANDARDIZATION OF
ANTIBIOTICS
 There are mainly three important points are for
standardization of antibiotics:
• FDA (Food Drug Administration) regulations governing all
aspects of antibiotics testing are completely detailed and are
subject to periodic amendment.
• FDA regulations need to be referred with regard to prescribed
method for the assay of individual antibiotics and their
preparations.
• During the evaluation of potency of antibiotic substances, the
actual and apparent measured effect is the degree of inhibition
of the growth of a suitable strain of microorganism i.e. the
prevention of the multiplication of the test organisms.

4. METHODS FOR STANDARDIZATION OF
ANTIBIOTICS
Two methods are usually
Cylinder-plate (or cup-plate)
Method
Turbidimetric Method
The cylinder-plate method depends
upon diffusion of the antibiotic
from a vertical cylinder through a
solidified agar layer in a Petri dish.
The growth of the added micro-
organism is prevented entirely in a
zone around the cylinder
containing a solution of the
antibiotic.
The cylinder-plate method depends
upon diffusion of the antibiotic
from a vertical cylinder through a
solidified agar layer in a Petri dish.
The growth of the added micro-
organism is prevented entirely in a
zone around the cylinder
containing a solution of the
antibiotic.

5. METHODS FOR STANDARDIZATION OF
ANTIBIOTICS
All the required ingredients are dissolved in
sufficient water to produce 1000 ml and added
sufficient amount of 1 M Sodium hydroxide or 1 M
Hydrochloride acid,
as required so that after sterilization the pH is
between 6.5 to 7.5.
Media Preparation:

6. Buffer Solution Preparation:
Buffer solutions are prepared by dissolving the required quantities of
dipotassium hydrogen phosphate
and potassium dihydrogen phosphate in sufficient water to produce
1000 ml
and pH adjusted with 8 M phosphoric acid or 10 M potassium
hydroxide.
METHODS FOR STANDARDIZATION OF
ANTIBIOTICS

7. Standard Preparation:
METHODS FOR STANDARDIZATION OF
ANTIBIOTICS
 Standard preparation is an authentic sample of the
appropriate antibiotic for which the potency has been
determined by reference to the appropriate international
standard.
 The potency of the standard preparation is expressed in µg
per mg of an international unit of the pure antibiotic.
 A stock solution is prepared by dissolved a required amount
of weighed quantity of the standard preparation of a given
antibiotic

8. Preparation of the Sample Solution:
Dilutions of sample or unknown samples are prepared at the range of
dilutions of standard prepared dilutions.
Test Organisms: Some of the test organisms for each antibiotic are
listed in
METHODS FOR STANDARDIZATION OF
ANTIBIOTICS

9. Assay Method of Streptomycin:
• Streptomycin is bactericidal antibiotic belongs to class
aminoglycosides. It is derived from actinobacterium Streptomyces
griseus.
• It is used against gram negative bacteria, mainly against
tuberculosis by inhibiting protein synthesis of microorganisms. It
is water soluble.
• Bacillus subtilis is used for the microbiological assay of
Streptomycin.
METHODS FOR STANDARDIZATION OF
ANTIBIOTICS