Self Emulsifying Drug Delivery System (SEDDS)

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Self-Emulsifying Drug Delivery System (SEDDS)
Presented by,
Mr.Panke Ashutosh Abhimanyu
M. Pharm-II Sem.
PUNE DISTRICT EDUCATION ASSOCIATION’S
Seth Govind Raghunath Sable College of Pharmacy, Saswad.
Department of Pharmaceutics
2014-15

Introduction
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 Self-emulsifying drug delivery systems
(SEDDS ) are defined as isotropic mixtures
of oils, surfactants and co-solvents.

Advantages
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1. Enhanced oral bioavailability
2. Selective targeting of drug(s) toward
specific absorption window in GIT.
3. Protection of drug(s) from the hostile
environment in gut.
4. Reduced variability including food effects.
5. Protective of sensitive drug substances.

Drawback Of SEDDS
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 Lack of good predicative in vitro models for
assessment of the formulations.
 The large quantity of surfactant in self-emulsifying
formulations (30-60%) irritates
 Volatile co-solvents can migrate on capsule
shell.

Composition of SEDDSs
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Composition of SEDDSs
 Drug (API)
 Oil
 Surfactant
Co-Surfactants

Drug
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The drugs with poor aqueous solubility and high permeability are classified as
class II drug by Biopharmaceutical classification system (BCS). These drugs are
use for formulate SEDDS.
Class II
Low Solubility
High Permeability
Class I
High Solubility
High Permeability
Class IV
Low Solubility
Low Permeability
Class III
High Solubility
Low Permeability
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Solubility

Oil
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 Oils are the most important excipient.
 Help in solubilizing the lipophilic drug in a high amount.
 Facilitate self-emulsification and increase the fraction of
lipophilic drug transported.
 Increase absorption from the GI tract.
 Both long-chain triglyceride and medium-chain triglyceride
oils with different degrees of saturation have been used for
the formulation of SEDDSs.

Lipid Ingredients
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 Corn oil
 Olive oil
 Sesame oil
 Soyabean oil
 Peanut oil
 Hydrogenated soyabean oil
 Hydrogenated vegetable oils

Surfactants
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 Non-ionic surfactants with high hydrophilic–lipophilic
balance (HLB) values are used in formulation of SEDDSs
 Surfactant strength ranges between 30–60% w/w of the
formulation in order to form a stable SEDDS.
 A large quantity of surfactant may irritate the GIT.
 Non-ionic surfactants are less toxic as compared to ionic
surfactants.

List of Surfactants
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 Polysorbate 20 (Tween 20)
 Polysorbate 80 (Tween 80)
 Sorbitan monooleate (Span 80)
 Polyoxy-40- hydrogenated castor oil

Co-solvents/Co-Surfactants
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 Co-solvents help to dissolve large amounts of
hydrophilic surfactants or the hydrophobic drug in
the lipid base.
 These solvents sometimes play the role as co-surfactant
in the micro-emulsion systems.

Co-solvents/Co-Surfactants
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Co-solvents Co-surfactants
 Span 20
 Span 80
 Capryol 90
 Lauroglycol
 Ethanol
 Glycerin
 Propylene glycol
 PEG

Mechanism of self emulsification
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 The free energy of the conventional emulsion is a
direct function of the energy required to create a
new surface between the oil and water phases
 In emulsification process the free energy (ΔG)
associated is given by the equation:

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where,
 ΔG = free energy associated with the process
(ignoring the free energy of mixing)
 N = number of droplets
 r = Radius of droplets
 б = interfacial energy

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 The two phases of emulsion tend to separate with
time to reduce the interfacial area, and subsequently,
the emulsion is stabilized by emulsifying agents.

General formulation Approach
 Preliminary solubility profiling studies are performed for
selection of oil.
 Drug excipient compatibility studies.
 Preparation of a series of SEDDS system containing drug
in various oil and surfactant with different combinations.
 Optimization of formulation on the basis of in vitro self-emulsification
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properties, droplet size analysis, stability
studies, robustness to dilution upon addition to water
under mild agitation conditions.

Evaluation of SEDDS
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1. Thermodynamic Stability Studies
2. Dispersibility test
3. Turbidimetric Evaluation
4. Viscosity Determination
5. Droplet Size Analysis and Particle Size Measurements
6. Refractive Index and Percent Transmittance
7. Electro Conductivity Study
8. In vitro Diffusion Study
9. Drug Content
10. In vivo permeability studies

Thermodynamic Stability Studies
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Heating cooling cycle
 Six cycles between refrigerator temperature 4⁰C
and 45⁰C with storage at each temperature of not
less than 48 h is studied.
 Those formulations, which are stable at these
temperatures, are subjected to centrifugation test.

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Centrifugation
 Passed formulations are centrifuged at room
temperature at 3500 rpm for 30 min.
 Those formulations that does not show any phase
separation are taken for the freeze thaw stress
test.

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 Freeze thaw cycle:-
 Freeze was employed to evaluate the stability of
formulation.
Thermodynamic stability was evaluated at difference
temp. To chake the effect of temp. the formulation was
subjected to freeze thaw cycle(-20ºC) for 2-3 days.

Freeze thaw cycle:-
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 Formulation are exposed to at least three freeze
thaw cycles. Those formulations passed this test
showed good stability with no phase separation,
creaming, or cracking.
 Suppose it shows thermodynamically unstable
formulation which had larger droplet size
distribution upon dilution.

Dispersibility test
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 The efficiency of self-emulsification of oral nano or micro
emulsion is evaluated by using a standard USP XXII
dissolution apparatus 2 for dispersibility test.
 Solution Tested: 1ml
 Medium: 500 ml water
 Temperature: 37 ± 1 ⁰C.
 Paddle speed : 50 rpm

Dispersibility test
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 Grade A: Rapidly forming (within 1 min) nano-emulsion, having
a clear or bluish appearance.
 Grade B : Rapidly forming slightly less clear emulsion having a
bluish white appearance.
 Grade C: Fine milky emulsion that formed within 2 min.
 Grade D: Dull, grayish white emulsion having slightly oily appearance
that is slow to emulsify (longer than 2 min).
 Grade E: Formulation, exhibiting either poor or minimal emulsification
with large oil globules present on the surface.
 Grade A and Grade B formulation will remain as nanoemulsion when
dispersed in GIT. While formulation falling in Grade C could be
recommended for SEDDS formulation.

Turbidimetric Evaluation
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 Nepheloturbidimetric evaluation is done to monitor
the growth of emulsification. Fixed quantity of Self
emulsifying system is added to fixed quantity of
suitable medium (0.1N hydrochloric acid) under
continuous stirring (50 rpm) on magnetic hot plate at
appropriate temperature, and the increase in
turbidity is measured, by using a turbidimeter
 However, since the time required for complete
emulsification is too short, it is not possible to
monitor the rate of change of turbidity (rate of
emulsification)

Viscosity Determination
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 The SEDDS system is generally administered in
soft gelatin or hard gelatin capsules. So, it should
be easily pourable into capsules and such
systems should not be too thick to create a
problem.The rheological properties of the micro
emulsion are evaluated by Brookfield viscometer.

Droplet Size Analysis
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 The droplet size of the emulsions is determined by
photon correlation spectroscopy (which analyses
the fluctuations in light scattering due to Brownian
motion of the particles) using a Zetasizer able to
measure sizes between 10 and 5000 nm.

Refractive Index and Percent Transmittance
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 Refractive index and percent transmittance prove the
transparency of formulation.
 The refractive index of the system is measured by
refractometer by putting a drop of solution on slide
and comparing it with water (1.333).
 The percent transmittance of the system is measured at
particular wavelength using UV spectrophotometer by
using distilled water as blank.
 If refractive index of system is similar to the refractive
index of water (1.333) and formulation have percent
transmittance > 99 percent, then formulation have
transparent nature.

Electro Conductivity Study
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 The SEDD system contains ionic or non-ionic
surfactant, oil, and water.
 This test is performed for measurement of the
electro conductive nature of system.
 The electro conductivity of resultant system is
measured by electro conductometer.
 In conventional SEDDSs, the charge on an oil
droplet is negative due to presence of free fatty
acids.

In vitro Diffusion Study
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 In vitro diffusion studies are carried out to study the
drug release behavior of formulation from liquid
crystalline phase around the droplet using dialysis
technique.

Drug Content
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 Drug from pre-weighed SEDDS is extracted by
dissolving in suitable solvent. Drug content in the
solvent extract was analyzed by suitable analytical
method against the standard solvent solution of
drug.

Conclusion
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Self‐emulsifying drug delivery systems are a
promising approach for the formulation of drug
compounds with poor aqueous solubility. The
oral delivery of hydrophobic drugs can be made
possible by SEDDSs, which have been shown to
substantially improve oral bioavailability. With
future development of this technology, SEDDSs
will continue to enable novel applications in drug
delivery and solve problems associated with the
delivery of poorly soluble drugs.

References
 P.A. Patel, et al Self Emulsifying Drug Delivery System: A Review, Research J.
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Pharm. and Tech. 1(4): Oct.-Dec. 2008,313-323.
 A.Kumar, et al Self Emulsifying Drug Delivery System (SEDDS): Future Aspect .
Int J Pharm Pharm Sci, Vol 2, Suppl 4, 713,7-13.
 J.Tang, et al Preparation of Self-emulsifying Drug Delivery Systems of Ginkgo
biloba Extracts and In vitro Dissolution Studies. Asian Journal of Traditional
Medicines, 2006, 1,3-4 .
 R. Sachan, et al Self-Emulsifying Drug Delivery System A Novel Approach for
enhancement of Bioavalibility. Pharm Tech Res.2010,2(3) 1738-1745 .
 M. Chitneni et al Intestinal Permeability Studies of Sulpiride Incorporated in to self-microemulsifying
drug delivery system (smedds) Pak. J. Pharm. Sci., .24,2, April
2011,.113-121.

Self Emulsifying Drug Delivery System (SEDDS)

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