Brief introduction to multiple emulsion, microemulsion,

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1. BRIEF INTRODUCTION TO MULTIPLE EMULSION, MICROEMULSION, NANOEMULSION & NANOSUSPENSION Presented by- Md . Shariq Ansari B.Pharm 5 th sem Under the guidance: M r. Dilip Kr. Patel

2. CONTENT Defination Emulsion Types Of Emulsions Identification test for emulsion Emulsifying agent Method of preparation of emulsion Microemulsion Nanoemulsion Nanosuspension

3. DEFINATION An Emulsion is a mixture of two or more liquids that are normally Immiscible . OR Emulsion, is a mixture of two or more liquids in which one is present as droplets, of microscopic or ultramicroscopic size, distributed throughout the other.

4. Emulsion Microemulsion Nanoemulsion Thermodynamically unstable Opaque High energy required to form Thermodynamically stable Clear It forms spontaneously Thermodynamically or kinetically stable Clear High shear application to form Int. J. Nanomed. 2014,9,pp 1-8

5. Internal Phase or External Phase in Emulsions: The dispersed liquid is known as the   Internal or Discontinuous phase. whereas the dispersion medium is known as the   External or Continuous phase . 

6. Based on size of liquid droplets: 0.2 – 50 mm Macroemulsions 0.01 – 0.2 mm Microemulsions

7. IDENTIFICATION TEST FOR EMULSIONS: By using Naked eye, it is very difficult to differentiate between o/w or w/o emulsions. Thus, the following methods have been used to identify the type of emulsions. Dye Test Dilution Test Electrical conductivity Test Fluorescence Test.

8. EMULSIFYING AGENT: Emulsions are stabilized by adding an emulsifying agent. These agents have both a hydrophilic and a Lipophilic part in their chemical structure. All emulsifying agents get adsorbed onto the Oil : water interface to provide a protective barrier around the dispersed droplets. In addition to this protective barrier, emulsifiers stabilize the emulsion by reducing the interfacial tension of the system. E.g. agar, albumin, cholic acid, glycerol, gums, soaps, casein, ox bile extract.

9. METHODS OF PREPARATION OF EMULSIONS: Commercially, emulsions are prepared in large volume mixing tanks and refined and stabilized by passage through a colloid mill or homogenizer. Extemporaneous production is more concerned with small scale methods. 1) Dry Gum Methods 2) Wet Gum Methods 3) Bottle Method

10. MICROEMULSION Micro Emulsions are dispersions of oil and water made with surfactant, co-surfactant molecules. In many respects, they are small-scale versions of emulsions. However, the droplet sizes are very small, typically 100 A, about 100 times smaller than typical emulsion droplet sizes. W/O O/W

11. OR “ Microemulsions are liquid dispersions of water and oil that are made homogenous, transparent (or translucent) and thermodynamically stable by the addition of relatively large amounts of a surfactant and a co-surfactant and having diameter of the droplets in the range of 100 – 1000 A (10 – 100 nm). (Figure : Microemulsion Structure)

12. Advantages of Microemulsions: . These are thermodynamically stable . . Require minimum energy for formation. . Easy of manufacturing . . Improved drug solubilization and bioavailability. . Wide applications in colloidal drug delivery systems. . The formation of microemulsion is reversible.  . Improve the efficacy of a drug & Minimum side effects. Disadvantages of Microemulsions: Use of a large concentration of surfactant and co-surfactants. Limited solubilizing capacity for high-melting substances. The surfactant must be nontoxic for using pharmaceutical applications. Microemulsion stability is influenced by environmental parameters such as temperature and pH.

13. NANOEMULSIONS Dispersion of two immiscible liquids stabilized by a surfactant Thermodynamically and kinetically stable Droplets from 5 to 200 nm

14. Nanoemulsions - Applications Agriculture Cleaning products Cosmetic Pharmaceutic Biomedical

15. Nanoemulsions - Drug Delivery Advantages Increase drug loading Enhance drug solubility Bioavailability Controlled drug delivery Protection of drug Disadvantages Expensive process Stability Solubility Lack of understanding of interfacial chemistry J. Phys. Chem. C  2008, 112 (33), 12669-12676 .

16. NANOSUSPENSION Definition: “A very finely dispersed solid drug particles in an aqueous vehicle in which diameter of suspended particle is less than 1 µm in size, stabilized by surfactants, for either oral and topical use or parentral and pulmonary administration, with reduced particle size, leading to an increased dissolution rate and therefore improved bioavailability”. Average particle size ranges from 200-600 nm. In nanosuspension technology, the drug is maintained in the required crystalline state with reduced particle size, Improved bioavailability leading to an increased dissolution rate.

17. ADVANTAGES Can be applied for the poorly water soluble drugs. Rapid dissolution and tissue targeting can be achieved by IV route of administration. Oral administration of nanosuspensions provide rapid and improved bioavailability . Long-term physical stability due to the presence of stabilizers. Nanosuspensions can be incorporated in tablets, pellets, hydrogels. 22

18. DISADVANTAGES Physical stability, sedimentation and compaction can causes problems. It is bulky sufficient care must be taken during handling and transport. Uniform and accurate dose cannot be achieved unless suspension . 23