This document discusses preservatives, which are substances added to pharmaceutical and cosmetic products to prevent microbial growth. An ideal preservative would be effective at low concentrations against all microorganisms, be nontoxic, compatible with other ingredients, and stable throughout the product's shelf life. Preservatives should not be irritants or toxic, be physically and chemically stable, compatible with other ingredients, and exert broad-spectrum antimicrobial activity at low concentrations throughout manufacturing and usage. Preservatives are classified based on their mechanism of action, such as antioxidants and antimicrobial agents, or source, such as natural preservatives like salt and artificial preservatives like benzoates. Common preservatives and their uses are also

1. Preservative
Presented by
Md. Faruk Ahmed
ID: 161-29-907
Daffodil International University

2. Definition
Preservatives are substances added to various pharmaceutical
dosage forms and cosmetic preparations to prevent or inhibit
microbial growth. An ideal preservative would be effective at low
concentrations against all possible micro-organism, be nontoxic
and compatible with other constituent of the preparation and be
stable for the shelf-life of the preparation.

3. Ideal Properties of Preservatives
 It should not be irritant.
 It should not be toxic.
 It should be physically and chemically stable.
 Preservative should be compatible with other ingredients used in
formulation.
 It should be act as good antimicrobial agent and should exert wide
spectrum of activity.
 It should act as preservative in small concentration i.e. it must be
potent.
 It should maintain activity throughout product manufacturing, shelf
life and usage.

4. Classification of preservative
Preservatives are classified on variety of the basis and some of these are as
follows:
Classification based on mechanism of action
a) Antioxidants: Eg. Vitamin E Vitamin C
b) Antimicrobial agents: Eg. Benzoates, Sodium benzoate, Sorbates
c) Chelating agents: Eg. Polyphosphates, Citric acid
CLASSIFICATION BASED ON SOURCE:
a) Natural Preservatives:-Eg. Neem Oil Salt (sodium chloride) Lemon
Honey.
b) Artificial Preservatives: Eg.Benzoates, Sodium benzoate Sorbates,
propionets, nitrites.

5. MECHANISM OF ACTION:
Preservative how they act?
Natural substances such as salt, sugar, vinegar, and diatomaceous earthare
also used as traditional preservatives. Certain processes such as freezing,
pickling, smokingand saltingcan also be used to preserve food. Another
group of preservatives targets enzymes in fruits and vegetables that continue
to metabolize after they are cut. For instance, citricand ascorbic acids from
lemonor other citrusjuice can inhibit the action of the enzyme phenolase
which turns surfaces of cut apples and potatoes brown. Caution must be
taken, however, since FDA standards do not currently require fruit and
vegetable product labels to accurately reflect the type of preservative used in
the products.

6. Some preservative & Use
 Benzoic acid:
Use: It is used as a food preservative, it inhibit the growth of mould, yeast
and some bacteria. It is also used externally as antiseptic.
 Boric acid:
Use: It is used as antiseptic, insecticide and flame retardant.
 Ethylparaben:
Use: It is used as preservative and food additive.
 Alcohols: Chloro butanol
Use: It is used as preservative and bacteriostatic agent.

7. Benzyl alcohol:
Use:It is used as bacteriostatic preservative.
 Mercurial Compounds: Phenylmercuric nitrate
Use: It is used as bacterial preservative in pharmaceutical
preparation and also used as topical antiseptic.

8. Thanks