1. DISPERSE SYSTEMS:COMPONENTS DISPERSED PHASEThe undissolved or immiscible drug(suspensoid) distributed throughout theliquid vehicle. Also called the internalphase

2. DISPERSION MEDIUMThe liquid vehicle, to which the insolubledrug is distributed. Also called externalphase 3. DISPERSE SYSTEMS PARTICLE SIZESColloidal dispersions 1 nm to 0.5 nm Coarse dispersions (suspensions andemulsions) 10 um to 50 um Fine dispersions ( magmas and gels) 0.5um to 10 um 4. SUSPENSIONS Disperse systems containing finely divided, insolubledrug particles (suspensoids) distributed somewhatuniformly throughout a liquid vehicle. Ready to use liquid form (antacids and analgesics)Labeled as Oral Suspension 5. REASONS for SUSPENSIONS For improving product stability Ease of administration and flexibility inadministration of a range of doses 6. Features desired inPharmaceutical Suspension 1. Particles should settle slowly and shouldbe readily re-dispersed upon shaking of thecontainer. 2. The particle size of the suspensoid shouldremain fairly constant throughout longperiods of undisturbed standing. 3. The suspension should pour readily andevenly from its container. 7. DISPERSED PHASE: PHYSICALFEATURES Particle diameter is 1m to 50m Particle size reduction is accomplished by:Micropulverization 10m-50mFluid energy grinding (jet milling ormicronization) under 10 m 8. PACKAGING AND STORAGE OFSUSPENSION packaged in wide-mouth containers havingadequate airspace above the liquid to permitthorough mixing by shaking and ease ofpouring stored in tight containers protected fromfreezing, excessive heat, and light. 9. EXAMPLES OF ORAL SUSPENSIONS Antacid Oral Suspensionsare intended to counteract the effects ofgastric hyperacidity and as such areemployed by persons, such as peptic ulcerpatients, who must reduce the level ofacidity in the stomach. They are also widelyemployed and sold over the counter (OTC)to patients with acid indigestion, heartburn,and sour stomach. 10. Antibacterial Oral Suspensions include preparations of antibiotic substances (e.g.,erythromycin derivatives, and tetracycline and itsderivatives), sulfonamides (e.g., sulfamethoxazole andsulfisoxazole acetyl), other anti- infective agents (e.g.,methenamine mandelate and nitrofurantoin), orcombinations of these (e.g., sulfamethoxazoletrimethoprim). 11. RECTAL SUSPENSIONS 12. EMULSIONSA dispersion in which the dispersed phase iscomposed of small globules of liquiddistributed throughout another liquid, inwhich it is immiscible. 13. PURPOSE OF EMULSIONS AND OFEMULSIFICATION Emulsification enables the pharmacist to preparerelatively stable and homogeneous mixtures of twoimmiscible liquids. It permits administration of a liquid drug in theform of minute globules rather than in bulk. For orally administered emulsions, the o/w typepermits palatable administration of an otherwisedistasteful oil by dispersing it in a sweetened,flavored aqueous vehicle. 14. TYPES OF EMULSIONSW/O emulsion - water is the internal phase- oil is external phase O/W emulsion - oil is the internal phase -water is external phase 15. THEORIES OF EMULSIFICATIONSURFACE-TENSION THEORYORIENTED WEDGE THEORY PLASTIC FILM OR INTERFACIAL FILMTHEORY 16. SURFACE-TENSION THEORYInitially, when oil and water are mixed itbecomes immiscible due to the presence ofsurface tension. The use of surfactants resultin the lowering of interfacial tensionbetween two immiscible liquids. 17. ORIENTED WEDGE THEORYThis theory assumes monomolecularlayers of emulsifying agent curved around adroplet of the internal phase. 18. PLASTIC FILM OR INTERFACIAL FILMTHEORYThis theory places the emulsifying agent atthe interface between the oil and water,surrounding the droplets of the internalphase as a thin layer of film adsorbed on thesurface of the drops. 19. PREPARATION OF EMULSIONSEmulsifying Agents the emulsifying agent must be compatible with theother formulative ingredients and must not interferewith the stability or efficacy of the therapeutic agent. It should be stable and not deteriorate in thepreparation. The emulsifier should be nontoxic with respect to itsintended use and the amount to be consumed by thepatient. Also, it should possess little odor, taste, orcolor 20. 1. Carbohydrate materials, such as the naturallyoccurring agents acacia, tragacanth, agar, chondrus,and pectin.2. Protein substances, such as gelatin, egg yolk, andcasein. These substances produce o/w emulsions3. Highmolecular-weight alcohols, such as stearylalcohol, cetyl alcohol, and glyceryl monostearate.These are employed primarily as thickening agentsand stabilizers for o/w emulsions of certain lotionsand ointments used externally.4. Wetting agents, which may be anionic, cationic, ornonionic.5. Finely divided solids such as colloidal clays,including bentonite, magnesium hydroxide, andaluminum hydroxide. 21. The HLB System HYDROPHILE LIPOPHILE BALANCEUsed to classify non-ionic surfactant.All NON IONIC surfactants have an HLB value. Thehigher the HLB number, the more hydrophilic. Thelower the HLB number, the more lipophilic 22. Application of Surfactants HLBVALUE SURFACTANT RANGEAPPLICATION 13 Antifoaming agents 36 Water-in-Oil emulsifiers 79 Wetting agents 8 18 Oil-in-Water emulsifiers 13 16 Detergents 15 20 Solubilizing agents 23. Methods of Emulsion Preparation WET GUM METHOD (English method) 4:2:1 ofoil : water : gum Formation of Primary Gum as thenucleus of the emulsion. DRY GUM METHOD (Continental method)4:2:1 ratio of oil: water: gum Formation of PrimaryMucilage as the nucleus of the emulsion BOTTLE METHOD (Forbes Bottle method)2:2: 1 ratio of oil : water : gum Applicable toemulsions containing Volatile Oils. 24. MICROEMULSIONThermodynamically stable systemOptically transparent isotropic mixture of abiphasic O/W system stabilized withsurfactantsDiameter of particle: 100 (10 m) to 1000 (Angstrom) 25. EXAMPLES OF ORAL EMULSIONSMINERAL OIL EMULSION OR LIQUIDPETROLATUM EMULSION>prepared by dry gum method>employed as lubricating agents with 30mldose 26. CASTOR OIL EMULSION Castor oil emulsion is used as a laxative forisolated bouts of constipation and inpreparation of the colon for radiography andendoscopic examination. the adult dose is 45 mL, about threetablespoonfuls. For children 2 to 6 years ofage, 15 mL is usually sufficient, and forchildren less than 2 years of age, 5 mL maybe given. 27. Simethicone Emulsion Simethicone emulsion is a water-dispersibleform of simethicone used as a defoamingagent for the relief of painful symptoms ofexcessive gas in the gastrointestinal tract. The emulsion in drop form is useful forrelief of gas in infants due to colic, airswallowing, or lactose intolerance. 28. Topical EmulsionUse to treat dry skin are o/w emulsionA number of topical emulsions, or lotionsare used therapeutically to deliver a drugsystemically.