Mr. Mayur Ravindra Patil.
First Year M. Pharmacy
R.G.SAPKAL COLLEGE OF PHARMACY,
DEFINITION OF SEDDS:-
Self-emulsifying drug delivery systems (SEDDS) or
self-emulsifying oil formulations (SEOF) are defined
as isotropic mixtures of natural or synthetic oils, solid
or liquid surfactants, or alternatively, one or more
hydrophilic solvents and co-solvents/surfactants.
SEDDS typically produce emulsions with a droplet size
between 100 and 300 nm while SMEDDS form transparent
micro-emulsions with a droplet size of less than 50 nm.
When compared with emulsions, which are sensitive and
metastable dispersed forms, SEDDS are physically stable
formulations that are easy to manufacture.
Upon mild agitation followed by dilution in aqueous
media, such as GI fluids, these systems can form fine
oil−in−water (o/w) emulsions or micro-
spread readily in the GI tract, and the digestive motility of
the stomach and the intestine provide the agitation
necessary for self-emulsification.
NEED FOR SEDDS.
40% of New Drug Candidates show poor aqueous
solubility and thus poor bioavailability.
BCS Class II DRUGS (Low solubility-High permeability)
– dissolution is rate limiting step for absorption.
E.g. of BCS Class II Drugs:-
Acetylsalicylic Acid, Ibuprofen, Captopril etc.
SEDDS emulsify spontaneously to
produce fine o/w emulsions when
introduced into aqueous phase under
gentle agitation, provided by the
peristaltic motility in GI tract, then
absorbed by lymphatic pathways.
HOW SEDDDS ACTS IN BODY??
1.The nature of the oil/surfactant pair.
2.The surfactant concentration.
4.The concentration and nature of co-surfactant and
5.Temperature at which self micro-emulsification occurs.
The Self-Emulsification Process Is Specific To The-
EXCEPIENTS USED IN SEDDS.
The oil represents one of the most important excipients in the
SEDDS formulation not only because it can solubilise marked
amounts of the liphophilic drug or facilitate self-emulsification
but also and mainly because it can increase the fraction of
liphophilic drug transported via the intestinal lymphatic system,
thereby increasing absorption from the GI tract depending on the
molecular nature of the triglyceride.
E.g.1. Triglyceride .
2.Hydrolyzed corn oil
4.Fractionated triglyceride of palm seed oil (medium-chain triglyceride)
5.Mixture of mono-and di-glycerides of caprylic/capric acid Medium
chain mono-and di-glycerides
10.Hydrogenated soybean oil
The most widely recommended ones being the non-ionic
surfactants with a relatively high hydrophilic−liphophilic
balance (HLB). The commonly used emulsifiers are various
solid or liquid ethoxylated polyglycolyzed glycerides and
polyoxyethylene 20 oleate (Tween 80).
Usually the surfactant concentration ranges between 30 and 60%
w/w in order to form stable SEDDS.
E.g. 1. Polyglycolyzed glycerides (HLB = 1−14)
2. Polyglycolyzed glycerides, POE−castor oil derivative
3. Maisine 35−1, Cremophor EL
The surfactant involved in the formulation of SEDDS should
have a relatively high HLB and hydrophilicity so that immediate
formation of o/w droplets and/or rapid spreading of the
formulation in the aqueous media (good self-emulsifying
performance) can be achieved. For an effective absorption, the
precipitation of the drug compound within the GI lumen should
be prevented and the drug should be kept solubilised for a
prolonged period of time at the site of absorption.
4.Polysorbate 20 (Tween 20)
The production of an optimum SEDDS requires
relatively high concentrations (generally more than
30% w/w) of surfactants. Organic solvents such as,
ethanol, propylene glycol (PG), and polyethylene
glycol (PEG) are suitable for oral delivery, and they
enable the dissolution of large quantities of either the
hydrophilic surfactant or the drug in the lipid base.
These solvents can even act as co-surfactants in
micro-emulsion systems. On the other hand,
alcohols and other volatile co-solvents have the
disadvantage of evaporating into the shells of the
soft gelatine, or hard, sealed gelatine capsules in
conventional SEDDS leading to drug precipitation.
self-emulsification takes place when the entropy change
favouring dispersion is greater than the energy required to
increase the surface area of the dispersion.
The free energy of a conventional emulsion formulation is a
direct function of the energy required to create a new surface
between the oil and water phases.
The two phases of the emulsion tend to separate with time to
reduce the interfacial area and thus the free energy of the
MECHANISM OF SELF-EMULSIFICATION.
Free energy in the micro-emulsion formation is directly
proportional to the energy required to create new surface
between the two phases, and is given by the equation-
Where, ΔG=Free energy associated with the process.
N=No. of droplets of radius r.
σ=Represents interfacial energy.
DIFFERENCE BETWEEN SEDDS AND
1. HIGHER SURFACTANT AND CO-
SURFACTANT /OIL RATIO:-
Combines advantages of lipid based drug
delivery systems with that of solid
Overcomes shortcomings of liquid
Eg.SE Tablets of Diclofenac,
advantages of s-seeds.
DRUG. TRADE NAME/
Cyclosporin A Neoral,Sandimmu
Ritonavir Norvir(Abbott) Soft gelatin
Sanquinavir Fortovase(Roche) Soft gelatin
Valproic acid Convulex
MARKETED ORAL SOLID SEDDS.
EVALUATION parameters of seeds.
1.Thermodynamic stability studies.
A. Heating cooling cycle.
C. Freeze thaw cycle.
5.Droplet Size Analysis Particle Size Measurements.
6.Refractive Index and Percent Transmittance.
7.Electro conductivity Study.
8.In Vitro Diffusion Study.
Self-emulsifying drug delivery systems are a promising approach
for the formulation of drug compounds with poor aqueous
The oral delivery of hydrophobic drugs can be made possible by
SEDDSs, which have been shown to substantially improve oral
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.
1.R Neslihan Gursoy, Simon Benita,.”Self-emulsifying drug
delivery systems (SEDDS) for improved oral delivery of
liphophilic drugs”;Hacettepe University, Faculty of
Pharmacy, Department of Pharmaceutical Technology,
06100 Ankara, Turkey; The Hebrew University of
Jerusalem, School of Pharmacy, Department of
Pharmaceutics, 91120 Jerusalem, Israel Received 10
2.Patel Nitesh N.,Rathva Sunil., Mr.ShahViral;Dr. Upadhyay
Umesh, ”Review on Self Emulsifying Drug Delivery System
Novel Approach for Solubility Enhancement”Sigma institute
Of Pharmacy1, Department Of Pharmaceutics, Vadodara,
3.Kommuru TR, Gurley B, Khan MA, Reddy IK.
Self‐emulsifying drug delivery systems (SEDDS) of
coenzyme Q10: formulation development and bioavailability
assessment. Int J Pharm 2001;212: 233‐46.