This seminar discusses disperse systems such as suspensions and emulsions. A disperse system is a heterogenous mixture with one phase dispersed within another continuous phase. Dispersions are classified by particle size as molecular, colloidal, or coarse dispersions. Coarse dispersions have particle sizes over 1000 nm and can be separated by filtration. Suspensions and emulsions are examples of coarse dispersions. The seminar describes formulation additives, production methods, and factors affecting stability for various disperse systems.

1. Seminar on
DISPERSE SYSTEM PRODUCTION
by
Nayala Firdous
(170713886005)
Under The Guidance Of
DR.MUQTADER
AHMED
M.Pharm,Ph.D
Head Of Department Of
Pharmaceutics
MASTER OF
PHARMACY
DEPARTMENT OF
PHARMACEUTICS
DECCAN SCHOOL
OF PHARMACY
Dar-us-salam, Aghapura,
Hyderabad-01. A.P. India
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2. INTRODUCTION
 A disperse system is defined as a heterogenous, two phase
system in which the internal (dispersed, discontinuous) phase
is distributed or dispersed within the continuous (external)
phase or vehicle.
 Based on the particle size of the dispersed phase,
dispersions are generally classified as
 Molecular dispersions
 Colloidal dispersions and
 Coarse dispersions.
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3. Classification of dispersed system by
particle size
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4. FORMULATION ADDITIVES
 Surfactants
 Protective Colloids and Viscosity-Imparting Agents
 pH-Controlling Agents
 Preservatives
 Antioxidants
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5. COARSE DISPERSION
 Coarse dispersions are heterogeneous dispersed systems, in
which the dispersed phase particles are larger than 1000 nm.
Coarse dispersions are characterized by relatively fast
sedimentation of the dispersed phase caused by gravity or
other forces. Dispersed phase of coarse dispersions may be
easily separated from the continuous phase by filtration.
 Includes:
a. Suspensions and
b. Emulsions
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6. SUSPENSION
 Typically, the suspensions with particle size greater than ~1
µm are classified as coarse suspension, while those below 1
µm are classified as colloidal suspension. When the particles
constituting the internal phase of the suspension are
therapeutically active, the suspension is known as
pharmaceutical suspension.
 Ideally, the internal phase should be dispersed uniformly
within the dispersion medium and should not sediment during
storage.
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7. Sedimentation and Stokes’ Law
 A flocculated suspension sediments faster and is
easy to redisperse, whereas a deflocculated
suspension sediments slowly and is difficult to
redisperse. The rate of sedimentation of particles
can be determined by Stokes’ law:
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8. Important Considerations in Formulation
of Suspension
 Nature of suspended material
 Size of suspended particles
a) Micropulverization
b) Fluid energy grinding
 Viscosity of the dispersion
medium
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9. EMULSION
 An emulsion is a dispersion of at least
two immiscible liquids, one of which is
dispersed as droplets in the other
liquid, and stabilized by an emulsifying
agent. Two basic types of emulsions
are the oil-in-water (O/W) and water-in-
oil (W/O) emulsion. Depending upon
the need, more complex systems
referred to as “double emulsions” or
“multiple emulsions” can be made,
water-in-oil-in-water (W1/O/W2) or oil-in-
water-in-oil (O1/W/O2).
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10. Mechanism of Emulsification
 When two immiscible liquids are in contact with each other,
the molecules at the interface experience an imbalance of
perpendicular forces. The interfacial tension tend to minimize
the surface area of individual liquids.
 The process of dispersion of one liquid in the other results in
an increase in surface area between the dispersed droplets
and dispersion medium, and surface free energy, which can
be expressed as follows:
∆W = γ∆ A
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11. HLB ranges of surfactants
 The amphiphilc nature of surfactants can be expressed in
terms of an empirical scale of so-called hydrophile–lipophile
balance (HLB) system, established by Griffin. The HLB
system provides a scale of hydrophilicity (0–20) and the
relationship between HLB values and the expected activity
from surfactants isHLB range Application
1–3 Antifoaming
3–6 W/O emulsifier
7–9 Wetting agent
8–18 O/W emulsifier
13–15 Detergent
15–18 Solubilizer
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12. COLLOIDS AND COLLIODAL DISPERSION
 A colloid is defined as a system consisting of discrete particles in
the size range of 1 nm to 1 mm, distributed within a continuous
phase.
 Molecules of a hydrophilic colloid have an affinity for water
molecules and when dispersed in water become hydrated.
Hydrated colloids swell and increase the viscosity of the system,
thereby improving stability by reducing the interaction between
particles and their tendency to settle.
 A hydrophobic colloid has little or no affinity for water
molecules in solution and produces no change in system
viscosity. 12Department of Pharmaceutics

13. GELS AND MAGMAS
 Gels in which the
macromolecules are
distributed so that no
apparent boundaries exist
between them and the
liquid are called single-
phase gels.
 When the gel mass
consists of floccules of
small, distinct particles, the
gel is classified as a two-
phase system and
frequently called
a magma or a milk.
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14. PARENTERAL DISPERSE SYSTEMS
Parenteral Emulsions Parenteral Suspensions
 In addition to the general
requirements for parenteral
products (e.g., sterility,
nontoxicity, and stability),
particular attention must be paid
to the droplet size and surface
charge of parenteral emulsions,
since these parameters can
directly affect both toxicity and
stability.
 Parenteral suspensions
consist of a solid phase, which
is dispersed within a liquid
phase.
 Because of particle sizes in
the micrometer range,
parenteral suspensions are
generally limited to either
subcutaneous or
intramuscular routes of
administration.
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15. EQUIPMENTS
PROPELLER MIXERS ROTOR/STATOR MIXER
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16. STATIC MIXER
 A static mixer is a precision engineered device for the continuous
mixing of fluid materials.
 The energy needed for mixing comes from a loss in pressure as
fluids flow through the static mixer.
 The typically helical elements can simultaneously produce patterns
of flow division and radial mixing.
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17. MICROFLUIDIZER TECHNOLOGY
 The interaction
chamber consist of
microchannels as
narrow as 50 microns
and cause the flow of
product to occur as
very thin sheets.
 Used to prepare
unilamellar liposomes
and micro emulsions.
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18. HIGH PRESSURE HOMOGENIZER
 The use of high pressure
homogenizers is
recommended when a
disintegration down to the
nano range is required.
 The pressure build-up within
the HPH occurs by means of
piston pump ensure(s) a
volume flow that is
independent of pressure and
virtually pulsation free.
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19. THREE ROLL MILLS
 A three roll mill is a
machine that uses shear
force created by three
horizontally positioned rolls
rotating in opposite
directions and different
speeds relative to each
other, in order to mix,
refine, disperse, or
homogenize viscous
materials fed into it.
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20. COLLOID MILL
 Colloid Mill is an ideal
and perfect
homogenizer-cum-
emulsifier. It finds its
application in various
processes like
grinding,
homogenizing,
emulsifying,
dispersing, mixin,
extracting etc.
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21. SUSPENSIONS STABILITY
PHYSICAL STABILITY CHEMICAL STABILITY
 Particle-particle interaction
and its behaviour
 Interfacial properties of solids
 Poly-dispersity: (variation in
particle size)
 Most of the drug materials
although insoluble, when
suspended in a liquid medium
has some intrinsic solubility,
which triggers the chemical
reactions such as hydrolysis,
to occur leading to
degradation.
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22. EMULSIONS STABILITY
PHYSICAL INSTABILITY CHEMICAL INSTABILITY
 Creaming (sedimentation)
and its avoidance.
 Flocculation prevention.
 Coalescence (breaking,
cracking)
 Oxidation
The rancidity is manifested by
the formation of degradation
products of unpleasant odour
and taste. These problems
can occur with certain
emulsifying agents, such as
wool fat or wool alcohols.
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23. REFERENCE
• Modern pharmaceutics, Forth edition Revised and
expanded edited by Gilbert S. Banker University of Iowa
Iowa City, Iowa Christopher T. Rhodes University of Rhode
Island Kingston, Rhode Island, Marcel Dekker, New York.
• Alok K Kulshreshtha, Onkar N. Singh, G. Micheal Wall
Pharmaceutical Suspension from formulation development
to manufacturing, Springer
• Pharmaceuticals dosage forms: disperse systems volume
2,3; Herbert A. Lieberman, Martin M. Rieger and Gilbert S.
Banker, informa health care.
• Ansel's Pharmaceutical Dosage Forms and Drug Delivery
Systems ninth edition, Loyd V. Allen, Jr. Nicholas G.
Popovich, Howard C. Ansel,
• Modern Pharmaceutics Volume 1 Basic Principles and
Systems edited by Alexander T. Florence Juergen
Siepmann, informa health care.
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