This document discusses emulsion and self-microemulsifying drug delivery systems (SMEDDS). It defines emulsions as mixtures of two immiscible liquids, while SMEDDS are isotropic mixtures of oils, surfactants, and cosurfactants that generate microemulsions upon gentle mixing with water. The document outlines the differences between emulsions and microemulsions, provides examples of formulations for various components of SMEDDS, and discusses stability testing and advantages such as improved drug solubility, stability, and patient compliance compared to other formulations.

1. EMULSION AND SMEDDS
SEPARATION AND
STABILITY
Presented by – Guided by -
AKASH DOMALE Dr. Abhijeet D Kulkarni Sir
Roll no – 02
Sanjivani College of Pharmaceutical
Education and Research

2. CONTENTS
 DEFINATION
 BACKGROUND
 INTRODUCTION
 DIFFRENCE BETWEEN EMULSION AND
MICROEMULSION
 FORMULATION
 STABILITY
 MARKETED PREPARATION

3. EMULSION: Emulsion is mixture of two or
more liquid that are normally immiscible
SMEDDS:
SMEDDS are defined as isotropic mixtures of
natural or synthetic oils, solid and liquid
surfactants.
DEFINITIONS

4.  Types of self microemulsion
1. o/w micro emulsion
2 .w/o micro emulsion

6. BACKGROUND
 Concept introduced by hoar and schulman in 1940’s who
generated a clear single phase solution by titrating a milky
emulsion with hexanol
 alternative names for these systems are often used such as
transparent emulsion ,swollen micelle,micellar solution and
solubilized oil.
 Schulman and co worker in 1959 subsequently coined the term
microemulsion.

7.  In recent years , much attention has been focused on oral
dosage form using a self micro-emulsifying drug delivery
system [SMEDDS] for the purpose of improving the
solubilityAnd absorption of poorly water soluble drug
 SMEDDS consists of a mixture of drug, oils ,surfactants and
other additives gentle mixing of these ingredients in aqueous
media generates microemulsion with droplet size in a range
of 10-100nm
 SMEDDS has been shown to improve absorption of drugs by
rapid self micro emulsification in the stomach ,with the micro
emulsion droplets subsequently dispersing in the
gastrointestinal tract to reach site of absorption
INTRODUCTION SMEDDS

9. Emulsion
1. Emulsion consists of roughly spherical
droplets of one phase dispersed to
other.
2. They are non transparent as the
particle/droplet size varies from 1-
20mm.
3. Formulation requires shaking.
4. They are thermodynamically unstable.
5. They are various formulation.
6. they are lyophobic.
1. They constantly evolve between
various structures ranging from
droplet to bi continuous structure
2. They are transparent as the particle/
droplet size is only 10-100nm.
3. It is constant formulation.
4. They are thermodynamically stable.
5. They can accommodate 20-40%
without increase in viscosity.
6. They are on the borderline between
lyophobic and lyophilic colloids.
Microemulsion

10. Composition of SMEDDS formulation
• Typically, a SMEDDS formulation comprises of drug,
oil, surfactant and co-surfactant
• Drug Lipophilicity and dose of the drug are the main
criteria to be considered before development of
SMEDDS formulation. Ideally, drug should have low
dose, log P 2 and should not possess extensive first
pass metabolism. The drug should show substantial
solubility in pharmaceutically accepted lipids,
surfactants and co-solvents

11. • Oils Medium chain triglycerides (MCT) having carbon
atoms between 6 and 12 are directly transported by portal
blood to the systemic circulation. Whereas, long chain
triglycerides (LCT) having carbon atoms greater than 12
are transported via intestinal lymphatics. As MCT have
higher solvent capacity and are also not subjected to
oxidation, they are widely used in lipid based formulations
Oils

12. • Surfactants form the interfacial film and lower the interfacial tension to
a small value which facilitates dispersion process.
• HLB value and concentration of surfactant is essential to be
considered while selecting a surfactant.
• For attaining high emulsifying performance, the emulsifier involved in
the formulation of SMEDDS should have high HLB greater than 12
which assists in formation of small o/w droplets and rapid spreading of
formulation in aqueous media.
• Generally, non-ionic surfactants with HLB412 are suggested for design
of self-dispersing systems as these are less toxic than ionic
surfactants
Surfactants

13. • Co-surfactants ensures flexibility of the interfacial layer,
i.e. it reduces the interfacial tension to a negative value.
• Co-surfactants form a flexible interfacial film in order to
acquire different curvatures required to form
microemulsion over a wide range of composition.
• Medium chain length alcohols (C3–C8) are commonly
employed as co-surfactants
CO-SURFACTANTS

14. Oil Phase
• Isopropyl Myristate
• Oleic acid
• Olive oil
• Mineral oil
• Medium chain triglyceride
• Soyabean oil
• Captex 355
• Isopropyl Palmitate
• Sunflower oil
• Safflower oil
Co-surfactant
• Propylene glycol
• Ethylene glycol
• Ethanol
• 1-butanol
• Isopropyl alcohol
• PEG 600
• Glycerol
• PEG 400
Surfactant
• Tween 80
• Tween 40
• Span 40
• Labrafil M1944CS
• Polyoxyethylene-35-
ricinoleate
• Brij 58
• CremophorEL
• Lecithin
EXAMPLE

15. Preparation of Smedds

16. (1) Storage: SMEDDS has the same advantage as emulsions, of facilitating the solubility of
hydrophobic drugs. Microemulsions undergo creaming over a period of time, whereas SMEDDS
being thermodynamically stable can be stored easily
(2) Stability: In contrast to micro/nanoemulsions, SMEDDS do not contain water and hence, they
have improved physical and/or chemical stability on long-term storage. Self-nanoemulsifying
tablets of carvedilol showed successful incorporation of carvedilol within the SNEDDS. This
resulted in improvement of the stability of carvedilol on dilution with aqueous media in the presence
of cellulosic polymers
(3)Compliance: Most of the SMEDDS formulations are in capsule or tablet dosage forms, thus
occupying smaller volume, easy to administer and hence improved patient compliance (
Advantages

17. (1) Drug precipitation on dilution: Diluted SMEDDS undergo precipitation of drug in
gastrointestinal fluid.
A common requirement for the lipid formulations is that they should be able to keep the
drug in the solubilized form in the gastrointestinal tract (GIT). Precipitation of the drug
from the system nullifies the advantage offered
by the lipid-based formulation system.
(2) The precipitation tendency of the drug on dilution is higher due to the dilution effect
of the hydrophilic solvent. It thereby requires incorporation of polymers to minimize drug
precipitation.
(3)Storage and handling: Liquid SMEDDS exhibit problems in handling, storage and
stability. Thus, formulating solid SMEDDS seems to be a logical solution to address
these problems.
DISADVANTAGE

18. Thermodynamic Stability Studies
• These studies are useful to evaluate the consequence of
temperature change on formulation.
• Formulation is diluted with aqueous phase and subjected to
centrifugation at 15,000 rpm for 15 min or at 3500 rpm for
30 min .
• The samples in which the phase separation is not observed
are subjected to freeze thaw cycles (−20°C and 40°C
temperature, resp.) and observed visually.
• The thermodynamically stable formulations will not show
any change in visual description .
.

19. In Vitro Dissolution Profile
• Drug release from formulation can be evaluated after filling the
formulation in a hard gelatin capsule using USP XXIII apparatus
I at 100 rpm [44, 64, 65] or USPXXIII apparatus II at 50 rpm or
with dialysis method [66] at °C.
• Samples at regular intervals should be withdrawn from the
medium and drug content is estimated and compared with the
control.
• The polarity of oil droplet has impact on drug release from the
diluted SMEDDS.
• The higher the polarity, the faster the drug release from the oil
droplet into the aqueous phase.
• Polarity is mainly dependent on the HLB of surfactant,
molecular weight of hydrophilic part of the surfactant, and its
concentration along with the degree of unsaturation of fatty
acid of lipid phase

20. 6.4.16. Stability Assessment
• Stability studies are performed as per the ICH
guidelines on the formulation which is filled in
gelatin capsules.
• At regular intervals the samples should be
collected and tested for appearance, color,
drug content, pH of diluted formulation, and
dissolution profile.
• If there is no change in all these properties
during storage conditions, formulation can be
concluded as stable formulation

22. 1. Spernath A, Aserin A (December 2006). "Microemulsions as carriers for drugs
and nutraceuticals".
Adv Colloid Interface Sci 128-130: 47–64. doi:10.1016/j.cis.2006.11.016. PMID
17229398.
2. Tang J: Self-Emulsifying Drug Delivery Systems: strategy for improving oral
delivery of poorly
soluble drugs. Cur Drug Th 2007; 2: 85-93.
3. Burcham DL, Maurin MB, Hausner EA and Huang SM: Improved oral
bioavailability of the
hypocholesterolemic DMP 565 in dogs following oral dosing in oil and glycol
solutions. Biopharmaceutics &
REFERENCES