Presented by : Sunil B. Kokate.
M. Pharm 3rd sem
Dept. of P’ceutics,
Govt. college of Pharmacy,
A) Introduction to Parentral suspension.
a) Formulation consideration.
b) Formulation development.
c) Evaluation of suspension.
B) Introduction to Parentral emulsion.
a) Formulation development.
b) Stability of emulsion.
c) Evaluation of emulsion.
Introduction: Parentral suspensions are dispersed, heterogeneous
systems containing insoluble drug particles which, when are to be
resuspended in either aqueous or oil vehicles before administering
to a patient.
They administered by either subcutaneous (S.C.) or intramuscular
For example procaine Penicillin G.
1) Sterility during its
storage & use.
2) Syringeability &
injectability of a suspension
are closely related to
viscosity & particle
3) Particle size should
be small & uniform.
4) Re‐ suspension
of particles occur
5) Dispersed particles do
not settle rapidly after
6) Cake formation not
occur during its shelf life.
7) Maintain its stability
and elegance during its
8) Isotonic &
9) Contain 0.5% to 5.0%
solids & particle size less
than 5 micrometer.
Advantages of parent
1) Better for drugs that are insoluble
in convention solvents.
2) Increased resistance to hydrolysis
& oxidation as drug is present in the
3) Formulation of controlled released
drug is possible
4) Elimination of hepatic first pass
1) Stabilization of suspensions for
the period between manufacture
& use present a number of
problems. e.g. solids gradually
settle & may cake, causing
difficulty in redispersion prior to
2) Maintenance of
physical stability is very
difficult in this dosage
4) Difficulty in manufacturing: Special
facilities required to maintain aseptic
condition for manufacturing processes such
as : crystallization, particle size
reduction, wetting, sterilization
5) Difficulty in
formulation: selecting the
ingredients, like suspending
agent, viscosity inducing
agent, stabilizers and
3) Non‐uniformity of
dose at the time of
Factors affecting release of drug from suspension:
1) Solubility of drug in biological fluids at the injection site.
2) Lipid solubility and oil-water partition coefficient of the drug.
3) pKa of the drug.
4) Dissolution rate of solid from its dosage from.
5) Particle size of the of drug in suspension.
6) Compatibility with other ingredient.
Preformulation data needed for the formulation development:
I. Particle size and particle size distribution.
IV. Solvates and polymorphs.
VI. pH stability.
Suspension ingredients: Parentral suspension contain both
active ingredient(s) and excipients.
Excipients used in the parentral preparations must be….
Physically and chemically compatible with active ingredient.
Nonpyrogenic, nontoxic, nonhaemolytic and nonirritating.
Must not interfere with the therapeutic effect of the active
Must maintain stability during sterilization and during the shelf
Effective at low concentration. 26/08/20139
b) Hydrophilic colloids: e.g. Sodium CMC, Acacia, Gelatin, MC, PVP.
c) Electrolytes: e.g. Potassium/sodium chloride, Potassium/sodium citrate,
2) Wetting agent: They reduce the contact angle between the surface of
the particle and the wetting liquid.
Useful when hydrophobic powders are suspended in aqueous systems.
e.g. Nonaqueous solvents (glycerin, alcohol, and propylene glycol).
Non ionic surfactant. (polysorbate 80, Polysorbate 20,Polysorbate 40).
3) Solvents: May be aqueous or non aqueous.
Water for injection is preferred aq. solvent system.
Non aqueous solvent may be..
i. Water miscible ( Ethanol, Glycerin, Propylene glycol, N-(β
ii. Water immiscible includes fixed oils like Sesame oil, Peanut
oil, Castor oil, almond oil, sunflower oil, iodinated poppy
Benzyl alcohol (0.9% to 1.5%), Methylparaben (0.18% to
0.2%), Propylparaben (0.02%), Benzalkonium chloride (0.01 % to
0.02%), and Thimersal (0.001 % to 0.01 %).
a) water soluble: Ascorbic acid- 0.02-0.1%, Sodium bisulfite- 0.1-
0.15%, Sodium metabisulfite- 0.1-0.15 %, Sodium formaldehyde
sulfoxylate- 0.1-0.15%, Thiourea- 0.005%
b) Oil soluble: Ascorbic acid esters-0.01-0.15, BHT-0.005-0.02%,
Two basic method used to prepare Parentral suspension are-
1. Aseptically combining sterile powder and vehicle
2. In situ crystal formation by combining sterile solutions.
Previously sterilized &
Vehicle & Excipients
(i.e. 0.22 micron)
1. Aseptically combining sterile powder and vehicle 26/08/201315
in solution (organic
(i.e. 0.22 micron)
(i.e. 0.22 micron)
(i.e. 0.22 micron)
2. In situ crystal formation by combining sterile solutions. 26/08/201316
Stability and Evaluation:
d) Sedimentation Volume.
e) Freeze‐Thaw cycles.
f) Crystal Growth.
g) Particle Size Measurement.
h) Zeta Potential determination.
i) Shipping Characteristic.
j) Product‐Package Interaction.
a) Sterility test.
b) Pyrogen test.
Official example of parentral suspension:
(1) Sterile ampicillin suspension USP’95 dispense as powder which
is to be reconstituted at time of administration.
(3) Tetanus toxoid adsorbed USP’95, IP’96 – aq. Suspension.
(4) Betamethasone acetate suspension USP’96 aq. Suspension.
(5) Insulin Zinc suspension USP’95, IP’96 aq. Suspension.
(6) Procaine penicillin suspension IP’96
Introduction: Parentral emulsion is O/W or W/O emulsion
with mean droplet diameter 200-500 nm.
Mainly employed as Total parentral nutrition's.
These are milky white in appearance.
W/O emulsion (S.C.).
O/W Sustained release depot preparation (I.M.).
O/W nutrient emulsion (I.V.)
A) Oils : The oils most commonly used are Long Chain
Triglycerides (LCTs) from vegetable sources (soybean or
sunflower oil. )
B) Emulsifiers: Natural and synthetic emulsifier are
a) Natural emulsifier- eg. lecithins.
b) Synthetic emulsifier- eg. Spans and Tweens.
C) Aqueous phase: a) Water for injection is aqueous phase for
b) Various substances have been added to the aqueous phase to
adjust osmolarity, pH.
D) Tonicity modifier :- Glycerol, sorbitol, xylitol are added in
E) Antioxidants :- α-tocopherol, ascorbic acid may be added in
aq. Phase to prevent peroxidation of unsaturated fatty acids.
F) Preservatives :- p-hydroxy benzoic acid (methyl and butyl
derivatives) can be dissolved in the aqueous phase.
1) The emulsifier, an
osmotic agent, and any
preservatives are usually
dissolved or dispersed in
the aqueous phase.
, and any lipophilic drugs
to be incorporated are
usually dissolved or
dispersed in the oil phase.
3) Both the phases are then
heated to 70-85 o C with
4) The coarse emulsion is
then formed by vigorous
stirring or mixing.
5) Final pH of formulation
A) Formulation Preparation:
B) Homogenization and particle size reduction: Can be
a) Ultrasonic homogenizers,
C) Filtration: Membrane filter is used for final filtration to
remove larger particles.
D) Sterilization: For large-volume (l00 to 1000 ml.) injectable fat
emulsions, sterilization is achieved by autoclaving.
Stability of parentral emulsions:
1) Stability of the formulation: Influenced by processing
conditions, autoclaving, storage conditions, excessive shaking, or
the addition of electrolytes or drugs.
2) Physical stability: Indicated by
a) Particle size changes.
c) Creaming, coalescence.
d) Extreme temperature fluctuation such as freezing can result in an
increased oil droplet size, leading to
aggregation, coalescence, and ultimate separation. 26/08/201325
3) Chemical Stability: Indicated by
c) Change in pH.
d) Rancidity of oil.
4) Microbiological Stability: For bacterial and fungal
Precaution should be taken to prevent microbial contamination
during processing and maintain sterility.
Evaluation of Emulsions:
1) Physical examination: Visual observation of
creaming, coalescence, and oil separation.
2) Chemical analysis: Determination and characterization of drug
substance, oil, phosphatide, and excipients present, including free fatty acids
and oxidative degradation products.
3) pH determination.
4) Particle size surface charges.
5) Sterility test.
6) Pyrogen test.
Packaging for parenteral Suspension and Emulsion:
Container components for parenteral products must be considered an integral part
of the product because they can dramatically affect product
stability, potency, toxicity, and safety.
Injectable suspension and emulsions provided in volumes of 100 to 1000 ml are
packaged in USP type I & II Glass bottles.
Siliconized Bottles with hydrophobic inner surface can be used.
Rubber closures are most commonly used.
Closures must not be permeable to oxygen or become softened by contact with
the oil phase of emulsion.
1) Lieberman H.A.,, Leon L. The Theory and Practice of Industrial
Pharmacy. Third edition, Varghese puglising house, Bombay, pp- 639-680.
2) Francoise N., Gilberte M. Pharmaceutical emulsion and suspension.
Marcel Dekker,inc, New York, pp- 229-270
3) Remington, The Science and Practice of Pharmacy 21th edition, Volume
I, Lippincott Williams & Wilkinss, pp- 802-836.
4) L.C. Collins-Gold, R.T. Lyons and L.C. Bartholow Parenteral emulsions
for drug delivery Advanced Drug Delivery Reviews, 5 189-208, 1990.
5) Rajesh M. Patel; Parenteral suspension: An overview ,International
Journal of Current Pharmaceutical Research Vol 2, Issue 3, 2010.