emulsion ppp

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Presentation Transcript

EMULSION:

EMULSION Kunal C Mehta Department of quality assurance Shree devi college of pharmacy

CONTENTS::

CONTENTS: Introduction Classification of emulsion Types of emulsion microemulsion Theories of emulsification Emulsifying agents Tests of emulsion Application of emulsion Physical parameter Chemical parameter Electrical repulsion Zeta potentiol Equipments

Slide 4:

An emulsion is a dispersion in which the dispersed phase is composed of small globules of a liquid distributed throughout a vehicle in which it is immiscible. Introduction EMULSIONS

Slide 5:

Based on dispersed phase Oil in Water (O/W): Oil droplets dispersed in water Water in Oil (W/O): Water droplets dispersed in oil Classification of emulsions : Based on size of liquid droplets 0.2 – 50 mm Macroemulsions (Kinetically Stable) 0.01 – 0.2 mm Microemulsions (Thermodynamically Stable)

Slide 6:

Emulsions encountered in everyday life! Metal cutting oils Margarine Ice cream Pesticide Asphalt Skin cream Stability of emulsions may be engineered to vary from seconds to years depending on application

Slide 7:

General Types of Pharmaceutical Emulsions: 1) Lotions 2) Liniments 3) Creams 4) Ointments 5) Vitamin drops

MICRO EMULSION:-:

MICRO EMULSION:- A microemulsion is considered to be a thermodynamically or kinetically stable liquid dispersion of an oil phase and a water phase, in combination with a surfactant. The dispersed phase typically comprises small particles or droplets, with a size range of 5 nm-200 nm, and has very low oil/water interfacial tension. Because the droplet size is less than 25% of the wavelength of visible light, microemulsions are transparent. TWO types of microemulsions are most likely to be formed depending on the composition: · Oil in water (o/w) microemulsions wherein oil droplets are dispersed in the continuos aqueous phase · Water in oil (w/o) microemulsions wherein water droplets are dispersed in the continuous oil phase;

Difference between Emulsions and Microemulsions :

Difference between Emulsions and Microemulsions Emulsion Size :- 0.5 to 50µm (but normally 0.5-5.0µm) Thermodynamically unstable. Phase separation may occur. Cloudy in appearance. Large input of energy during their preparation Microemulsion Size :- 0.1 – 1.0µm. Thermodynamically stable. Phase separation never occur. Translucent & clear Low input of energy during their preparation as compare to emulsion.

Advantages Of Microemulsion Over Other Dosage Forms:

Advantages Of Microemulsion Over Other Dosage Forms Increase the rate of absorption Eliminates variability in absorption Helps solublize lipophilic drug Provides a aqueous dosage form for water insoluble drugs Increases bioavailability Various routes like topical, oral and intravenous can be used to deliver the product Rapid and efficient penetration of the drug moiety Helpful in taste masking Provides protection from hydrolysis and oxidation as drug in oil phase in O/W microemulsion is not exposed to attack by water and air. Liquid dosage form increases patient compliance. Less amount of energy requirement.

Characterization Of Microemulsion:

Characterization Of Microemulsion Following shall be performed to characterize the microemulsion :- droplet size, viscosity, density, turbidity, refractive index, phase separation and pH measurements.

Application of microemulsion:

Application of microemulsion Controlled & sustained drug delivery Drug targeting Vaccine adjuvant Immobilisation of enzyme Absorption enhancement through gastrointestinal tract Food & cosmetic application Miscellaneous Taste masking action Protection action As sorbent reservoir in drug overdose treatment.

Slide 14:

Theories of Emulsification : 1) Surface Tension Theory: - lowering of interfacial tension. 2) Oriented-Wedge Theory: - mono molecular layers of emulsifying agents are curved around a droplet of the internal phase of the emulsion. 3) Interfacial film theory: - A film of emulsifying agent prevents the contact and coslescing of the dispersed phase.

Slide 15:

Emulsifying Agents: It is a substance which stabilizes an emulsion . Pharmaceutically acceptable emulsifiers must also : be stable . be compatible with other ingredients . be non – toxic . possess little odor , taste , or color . not interfere with the stability of efficacy of the active agent .

Slide 16:

Emulsion Type and Means of Detection: Tests for Emulsion Type (W/O or O/W emulsions) 1) Dilution Test: - o/w emulsion can be diluted with water. - w/o emulsion can be diluted with oil. 2) Conductivity Test: Continuous phase water > Continuous phase oil.

Slide 17:

4) Refractive index measurement 5) Filter paper test 3) Dye-Solubility Test: - water soluble dye will dissolve in the aqueous phase. - oil soluble dye will dissolve in the oil phase.

APPLICATIONS OF EMULSION: :

APPLICATIONS OF EMULSION: Continue to have a variety of cosmetic & pharmaceutical applications. Most popular in oral & topical dosage form- as undoubtedly patient acceptance. When medicinal agent formulated into emulsions it become more palatable for oral administration Oil soluble vitamins,oil -based laxatives,high –fat nutritive preparations are commonly administered as o/w emulsions.

Slide 19:

Some drugs are more readily absorbed when they are administered orally in the form of emulsions. Normally unabsorbable macromolecules such as insulin & heparin are absorbed when they are in emulsion form Its possess certain degree of elegance & are easily washed off whenever desired Formulator can control the viscosity , appearance and degree of greasiness of cosmetic or dermatologic emulsions.

Slide 20:

w/o emulsion employed more widely for treatment of dry skin and emollient applications Process of penetration into the skin is facilitated if the emulsion is thixotropic ..i.e., it become less viscous during shearing Used for intavenous administration of lipid nutrients, which is facilitated by emulsification

Slide 21:

Radiopaque emulsions have been used as diagnostic agents in x-ray examinations. w/o emulsions have been employed to disperse water soluble antigenic materials in mineral oil for intramuscular depot injection. Emulsification of perfluorinated hydrocarbons is required to make them useful as oxygen carriers in blood replacements

Physical parameters::

Physical parameters: Application of energy in the form Heat Mechanical agitation Ultrasonic vibration Electricity Required to reduced the internal phase into small droplets.

Slide 23:

Amount of work input depends on the length of time during which energy is supplied.. So timing is also imp parameter. Heat : The interactions are complex So its impossible to predict whether a rise in temperature will favour emulsification or coalescence.

Slide 24:

increase in temperature--- decrease interfacial tension & viscosity So can predict ------- emulsification is favoured by an increase in temperature..

Slide 25:

Phase inversion temperature : The temperature at which the inversion occurs depends on emulsifier concentration and is called phase inversion temperature.. This type of inversion can occur during the formation of emulsions, since they are generally prepared at relatively high temperature and are then allowed to cool to room temperature.

Slide 26:

Timing: Briggs showed that the best way of forming an emulsion by this technique is to used intermittent shaking.. Timing or scheduling also affects the speed with which the two immiscible liquids are blended. Cooling rate of the initially formed emulsion also has a profound influence on the ultimate characteristics of the emulsion.

Chemical parameters::

Chemical parameters: It is difficult to designate a general approach or a set of rules for selecting the components and their amounts to yield a desired emulsion. Selection is made on the basis of the experience & personal tastes of the formulator and by trial error.

Slide 28:

choice of the lipid phase: final consideration in the selection of a lipid component for a topical preparation is its “feel”. Emulsion normally leave a residue of the oily components on the skin after the water has evaporated. So tactile characteristics of the combined oil phase are of great importance in determining consumer acceptance of an emulsion.

Slide 29:

Phase ratio: The ratio of the internal phase to the external phase is frequently determined by the solublity of the active ingredient. If not by this then phase ratio is determined by the desired consistency.

Slide 30:

Choice of emulsifying agents: 3 broad classes : Surfactants Hydrophilic colloids Finely divided solids Particular class of emulsifier is selected primarily on the basis of required “shelf-life” stability, Type of emulsion desired , An emulsifier cost

Slide 31:

Choice of surfactant: To systematize the hydrophilic/ lipophilic approach to emulsifier selection, Griffin in 1947 developed the system of the hydrophilic- lipophilic balance(HLB) of the surfactants Griffin defined the HLB value of a surfactant as the mol % of the hydrophilic group divided by 5. A completely hydrophilic molecule has an HLB value of 20.

Slide 32:

Choice of an antimicrobial preservative: Emulsion often contain Carbohydrate Proteins Sterols Phosphatides Which are support the growth of a variety of microorganisms

Slide 33:

General criteria of preservatives: Low toxicity Stability to heat & storage Chemical compatiblity Resonable cost Acceptable taste Odor Color Efficacy against variety of organisms

Slide 34:

Choice of antioxidant: Many organic compounds are subject to autoxidation upon exposure to air and emulsified lipids are particularly sensitive to attack. Upon autoxidation ,unsaturated oils ,such as vegetable oils, give rise to rancidity with resultant unpleasant odour,appearance and taste, E.g of antioxidants: Gallic acid Butylated hydroxytolune Butylated hydroxyanisol Ascorbyl palmitate

Formulation::

Formulation: Oil phase (or) oil : Vegetable oil (fixed or natural) e.g..corn oil,sunflower oil,soyabean oil etc. They should be of highest purity. 2) Emulsifying agents : These are classified as 1 ⁰ & 2 ⁰. 1⁰ emulsifying agent:- natural lecithine and soyabean . it is stable emulsifying agent & remain during formulation.

Slide 36:

2⁰ emulsifying agent :- like paloxamers is used which is non ionic surfactant & non toxic. 3) Tonicity contributor :- other are tweens & spans Used for osmotic pressure. It is usually 5% dextrose. Nacl being an electrolyte can break the emullsion . Glycerine :-2.25 to 2.5% 4) Vehicle :- mainly WFI

Electrical repulsion::

Electrical repulsion: The film can produce repulsive electrical forces between approaching droplets. Such repulsion is due to an electrical double layer, which may arise from electrically charged groups oriented on the surface of emulsified globules. E.g..sodium soap the hydrocarbon tail is dissolved in the oil droplet, while, the ionic heads are facing the countinous aqueous phase.

Slide 38:

As a result, the surface of the droplet is studded with charged groups,in this case negatively charged carboxylate groups. This produced a surface charge on the droplet, while cations of opposite sign are oriented near the surface,producing what is known as the ( diffuse ) double layer of charge.

Zeta potential::

Zeta potential: Can be measured with the aid of the moving boundry method or, by observing the movement of particles under the influence of electrical current. Its useful for assessing flocculation since electrical charges on particals influence the rate of flocculation. The measurment of electrical conductivity has been claimed to be a powerful tool for the evalution of emulsion stability shortly after preparation.

EQUIPMENTS:

EQUIPMENTS Various types of equipment are available to effect droplet breakup and emulsification Divided into 4 broad categories: Mechanical stirrers Homogenizers Ultrasonifiers Colloid mills

Slide 42:

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Reference ::

Reference : “ The Theory and Practice of Industrial Pharmacy” Indian Edition 2009 by Leon Lachman Herbert A.Liberman page no-502 to 531 www.pharmpedia.com www.techceuticals.com www.images .com

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