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Suspension
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 Suspension:
A suspension is a two-phase
system consisting of a finely divided solid
particles dispersed in liquid, or gas.
And
 Pharmaceutical Suspension. A liquid
preparation containing undissolved material.
A"SHAKE WELL" label is applied to the
container
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Parts of the Suspension
Suspension
is made of two
phase system, consisting of a
finely divided solid particles
(Dispersed phase) distributed
in a particular manner
throughout another medium
(Continuous phase).
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Suspension
Continuous phase
(Dispersion medium)
Dispersed phase
Particle size of Dispersed phase Iess than 1 micrometer (µm)
Particle size of Dispersed phase more than 1 micrometer (µm)
Colloid
Suspension
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Compositions Of
Pharmaceutical Suspension
Insoluble particles
Liquid medium
Main parts
Suspending agent
Surfactant
Viscosity enhancer
Preservative
Favoring agent
Excipients
Sweetener
Colours
Buffers
Stabilizers
*The order in which these ingredients are blended is important to the stability of the
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preparation
Pharmaceutical application of
suspension
Patients
compliance
Improve solubility
Mask taste
Fast absorption
Improve stability for drugs
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Pharmaceutical Applications of Suspension
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Patients who have problems in swallowing solid
dosage forms require drugs to be dispersed in a liquid.
Oral suspensions permit the formulation of poorly
soluble drugs in the form of liquid dosage form.
Drugs, which possess unpleasant taste in solution
dosage form like paracetamol, chloramphenicol
palmitate etc. can be formulated as palatable
suspension as they are suitable for administration to
peadiatric patients.
The rate of absorption of a drug from suspension is
usually faster than solid dosage form but slower than
solution.
If drug is unstable when in contact with vehicle,
suspension should be prepared immediately prior to
handing out to the patient in order to reduce the
amount of time that the drug particles are in contact
with dispersion medium. e.g Ampicillin suspension
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Routes of administration of suspension
External use (Topical )
Oral administration
Ophthalmic
Otic
Parenteral suspensions
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Routes of administration of
suspension
 External use
(Topical): There consistency
range from fluid to paste. e.g fluid suspension
calamine lotion. Zinc cream consists of high
percentage of powders dispersed in an oily
(paraffin) phase.
 Oral administration: non sterile dispersion
 Ophthalmic and Otic: sterile and possess
very fine particles
 Parenteral suspensions: sterile e.g Vaccines
formulated as dispersions
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Injectable Suspensions
 Suspensions
contain less than 5% of drug
solid with mean particle diameter within 510 µm.
 Owing to the presence of particles in these
formulations , these particles are more
difficult to process and sterilize than
solution for injection
 During the manufacture of suspension for
injection the components are prepared
and sterilized separately.
 They are then aseptically combined
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Injectable Suspensions
 The
final product of injectable suspension
can not be filter sterilized owing to the
presence of particles in the formulation.
 Powders for use in sterile suspensions can
be sterilized by gas , but gas residues
must be avoided.
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Suspensions are useful formulation
for Inhalations
 The
volatile component are adsorbed onto
the surface of the diffusible solid to ensure
uniform dispersion throughout the liquid.
 An example for a suspension used for
inhalation is menthol and eucalyptus
 These materials used as an adjunct to
fluid replacement in acute diarrhea
treatment
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Aerosols: another form for
pharmaceutical suspension
*Aerosols are dispersions of a
liquid or solid in air.
*Many pharmaceutical aerosols
consist of solids dispersed in a
non-aqueous propellant or
propellant mixture.
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