Dr. Yasmin Mortagi
Lecturer of Pharmaceutics
Faculty of Pharmacy, Al-Arish Branch
sinaiuniversity.net
Physical Pharmacy
(PT 202)
Lecture No. 7
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INDEX
• Structural
Item No. 1 Classification of SAA
P. 08
45
• Ionic
Surface Active
Agents of functional groups
Characteristic
IR absorptions
P. 12
45
• Non-ionic
Surfactants
IR figures of
functional groups
P. 21
47
• Amphoteric
IR Problems surfactants
P. 49
37
• Applications of Surface Active Agents
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P. 50
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Structural classification of Surface active agents
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Surfactant
Ionic SAA
Non-Ionic SAA
cataionic SAA
anionic SAA
Soap
Amphoteric SAA
Alkyl sulfates
Ether linked
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Alkyl
sulfonates
Ester linked
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Ether-ester
linked
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I. Ionic SAA
a) Anionic SAA
1- Soaps:
(Used as Detergents)
- The oldest SAA.
- They are generally metal salts of long chain fatty acids.
- They have the general formula:
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2-Organic sulfates
or (Alkyl sulfates)
3-Alkyl sulfonate
Sodium dodecyl
benzenesulfonate
Sodium dodecyl sulfate or
sodium lauryl sulfate, USP,
(Used as detergent and
germicidal agent)
(Used as detergents in
toothpastes and ointments)
CH3 (CH2)11 – OSO-3 Na+
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b) Cationic surfactants
• They ionized in water bearing a positive charge and possess the surface
active portion of their molecule in the cations. These are mainly quaternary
ammonium compounds.
• the cationic SAA have marked bactericidal activity against
microorganisms.
Dodecyl dimethyl benzyl ammonium
chloride: Benzalkonium chloride
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Cetyl trimethyl ammonium bromide:
Cetrimide
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II Non-ionic SAA
Ether Linked SAA
E.g Brij
R – O – (CH2 CH2 O)n H
They are widely used in the preparation of O/W
emulsions, as wetting agents and as solubilizing agents.
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Ester Linked Surfactants
E.g: Span
Estrification of sorbitan with fatty acid such as, lauric, stearic or oleic produces the
nonionic SAA:
Sorbitan mono-Laurate (Spans 20)
Sorbitan mono-Stearate (Span 60)
and Sorbitan mono-oleate (Span 80)
They are used in the preparation of W/O emulsions.
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Ester Linked Surfactants
E.g Span
Estrification of sorbitan with fatty acid such as, lauric, stearic or oleic
produces the nonionic SAA:
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Ester–Ether Linked SAA : (Tweens)
These are produced by reacting the free –OH groups in spans
(sorbitan fatty acid esters) with ethylene oxide
Polyoxyethylene sorbitan mono-Laurate or Polysorbate-20 (tween 20).
Polyoxyethylene sorbitan mono-Stearate or Polysorbate-60 (tween 60).
Polyoxyethylene sorbitan mono-oleate or Polysorbate-80 (tween 80).
They are O/W emulsifiers.
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III - Amphoteric surfactants:
Zwitterionic
They are the least common of the ionic group. The performance or
behavior of this group is pH dependent and they can function as
anionic or cationic SAA.
Example:
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H2
CH3 (CH2)11 – N+– CH2 – CH2 – COO –
N- Dodecyl 2-aminopropionic acid
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Applications of Surface Active Agents
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1- Foaming Agents
Foaming agents are surfactants, which facilitate
the formation of air globules inside water film
and stabilize them. They are important for
toothpaste and fire extinguishing products.
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2- Antifoam Effect
• Antifoams are surface-active agents have low HLB
(1–3). They destroy air pockets.
• Antifoaming agents are important for manufacturing
most pharmaceutical liquid preparations containing
SAA for wetting or flocculating effect. They reduce
the foam formation during the manufacturing process.
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3- Detergents
• These are surfactants used to remove the dirt. The process of
detergency is complex:
1- Initial wetting of the dirt and of the surface to be cleaned.
2-Deflocculation and suspension of dirt materials.
3- Emulsification or solubilization of the dirt particles.
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THANK
YOU
For any questions feel free
to contact me by mail
Yasmin.mohamed@s
u.edu.eg
Dr. Yasmin Mortagi
Lecturer of Pharmaceutics
Faculty of Pharmacy, Al-Arish Branch