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byNayala Firdous (170713886005)

Under The Guidance Of DR.MUQTADER AHMEDM.Pharm,Ph.DHead Of Department Of Pharmaceutics


1Department of PharmaceuticsINTRODUCTIONA disperse system is defined as a heterogenous, two phase system in which the internal (dispersed, discontinuous) phase is distributed or dispersed within the continuous (external) phase or vehicle. Based on the particle size of the dispersed phase, dispersions are generally classified as Molecular dispersionsColloidal dispersions and Coarse dispersions.2Department of PharmaceuticsClassification of dispersed system by particle size

3Department of PharmaceuticsFORMULATION ADDITIVESSurfactantsProtective Colloids and Viscosity-Imparting AgentspH-Controlling AgentsPreservativesAntioxidants

4Department of PharmaceuticsCOARSE DISPERSIONCoarse dispersions are heterogeneous dispersed systems, in which the dispersed phase particles are larger than 1000 nm. Coarse dispersions are characterized by relatively fast sedimentation of the dispersed phase caused by gravity or other forces. Dispersed phase of coarse dispersions may be easily separated from the continuous phase by filtration.Includes:Suspensions andEmulsions 5Department of PharmaceuticsSUSPENSIONTypically, the suspensions with particle size greater than ~1 m are classified as coarse suspension, while those below 1 m are classified as colloidal suspension. When the particles constituting the internal phase of the suspension are therapeutically active, the suspension is known as pharmaceutical suspension.Ideally, the internal phase should be dispersed uniformly within the dispersion medium and should not sediment during storage.6Department of PharmaceuticsSedimentation and Stokes LawA flocculated suspension sediments faster and is easy to redisperse, whereas a deflocculated suspension sediments slowly and is difficult to redisperse. The rate of sedimentation of particles can be determined by Stokes law:

7Department of PharmaceuticsImportant Considerations in Formulation of SuspensionNature of suspended materialSize of suspended particlesa)Micropulverizationb) Fluid energy grindingViscosity of the dispersion medium

8Department of PharmaceuticsEMULSIONAn emulsion is a dispersion of at least two immiscible liquids, one of which is dispersed as droplets in the other liquid, and stabilized by an emulsifying agent. Two basic types of emulsions are the oil-in-water (O/W) and water-in-oil (W/O) emulsion. Depending upon the need, more complex systems referred to as double emulsions or multiple emulsions can be made, water-in-oil-in-water (W1/O/W2) or oil-in-water-in-oil (O1/W/O2).

9Department of PharmaceuticsMechanism of EmulsificationWhen two immiscible liquids are in contact with each other, the molecules at the interface experience an imbalance of perpendicular forces. The interfacial tension tend to minimize the surface area of individual liquids. The process of dispersion of one liquid in the other results in an increase in surface area between the dispersed droplets and dispersion medium, and surface free energy, which can be expressed as follows:W = A

10Department of PharmaceuticsHLB ranges of surfactantsThe amphiphilc nature of surfactants can be expressed in terms of an empirical scale of so-called hydrophilelipophile balance (HLB) system, established by Griffin. The HLB system provides a scale of hydrophilicity (020) and the relationship between HLB values and the expected activity from surfactants isHLB rangeApplication13Antifoaming36W/O emulsifier79Wetting agent818O/W emulsifier1315Detergent1518Solubilizer11Department of PharmaceuticsCOLLOIDS AND COLLIODAL DISPERSIONA colloid is defined as a system consisting of discrete particles in the size range of 1 nm to 1 mm, distributed within a continuous phase. Molecules of ahydrophilic colloidhave an affinity for water molecules and when dispersed in water become hydrated. Hydrated colloids swell and increase the viscosity of the system, thereby improving stability by reducing the interaction between particles and their tendency to settle.Ahydrophobic colloidhas little or no affinity for water molecules in solution and produces no change in system viscosity. 12Department of PharmaceuticsGELS AND MAGMASGels in which the macromolecules are distributed so that no apparent boundaries exist between them and the liquid are calledsingle-phase gels.

When the gel mass consists of floccules of small, distinct particles, the gel is classified as a two-phase system and frequently called amagmaor amilk.

13Department of PharmaceuticsPARENTERAL DISPERSE SYSTEMSParenteral EmulsionsParenteral SuspensionsIn addition to the general requirements for parenteral products (e.g., sterility, nontoxicity, and stability), particular attention must be paid to the droplet size and surface charge of parenteral emulsions, since these parameters can directly affect both toxicity and stability.Parenteral suspensions consist of a solid phase, which is dispersed within a liquid phase. Because of particle sizes in the micrometer range, parenteral suspensions are generally limited to either subcutaneous or intramuscular routes of administration.14Department of PharmaceuticsEQUIPMENTSPROPELLER MIXERSROTOR/STATOR MIXER

15Department of PharmaceuticsSTATIC MIXERAstatic mixeris a precision engineered device for the continuous mixing of fluid materials.The energy needed for mixing comes from a loss in pressure as fluids flow through the static mixer.The typicallyhelicalelements can simultaneously produce patterns of flow division and radial mixing.

16Department of PharmaceuticsMICROFLUIDIZER TECHNOLOGYThe interaction chamber consist of microchannels as narrow as 50 microns and cause the flow of product to occur as very thin sheets.Used to prepare unilamellar liposomes and micro emulsions.

17Department of PharmaceuticsHIGH PRESSURE HOMOGENIZERThe use of high pressure homogenizers is recommended when a disintegration down to the nano range is required.The pressure build-up within the HPH occurs by means of piston pump ensure(s) a volume flow that is independent of pressure and virtually pulsation free.

18Department of PharmaceuticsTHREE ROLL MILLSA three roll mill is a machine that uses shear force created by three horizontally positioned rolls rotating in opposite directions and different speeds relative to each other, in order to mix, refine, disperse, or homogenize viscous materials fed into it.

19Department of PharmaceuticsCOLLOID MILLColloid Mill is an ideal and perfect homogenizer-cum-emulsifier. It finds its application in various processes like grinding, homogenizing, emulsifying, dispersing, mixin, extracting etc.

20Department of PharmaceuticsSUSPENSIONS STABILITYPHYSICAL STABILITYCHEMICAL STABILITYParticle-particle interaction and its behaviourInterfacial properties of solidsPoly-dispersity: (variation in particle size)

Most of the drug materials although insoluble, when suspended in a liquid medium has some intrinsic solubility, which triggers the chemical reactions such as hydrolysis, to occur leading to degradation.21Department of PharmaceuticsEMULSIONS STABILITYPHYSICAL INSTABILITYCHEMICAL INSTABILITYCreaming (sedimentation) and its avoidance.Flocculation prevention.Coalescence (breaking, cracking)OxidationThe rancidity is manifested by the formation of degradation products of unpleasant odour and taste. These problems can occur with certain emulsifying agents, such as wool fat or wool alcohols. 22Department of PharmaceuticsREFERENCEModern pharmaceutics, Forth edition Revised and expanded edited by Gilbert S. Banker University of Iowa Iowa City, Iowa Christopher T. Rhodes University of Rhode Island Kingston, Rhode Island, Marcel Dekker, New York.Alok K Kulshreshtha, Onkar N. Singh, G. Micheal Wall Pharmaceutical Suspension from formulation development to manufacturing, SpringerPharmaceuticals dosage forms: disperse systems volume 2,3; Herbert A. Lieberman, Martin M. Rieger and Gilbert S. Banker, informa health care.Ansel's Pharmaceutical Dosage Forms and Drug Delivery Systems ninth edition, Loyd V. Allen, Jr. Nicholas G. Popovich, Howard C. Ansel, Modern Pharmaceutics Volume 1 Basic Principles and Systems edited by Alexander T. Florence Juergen Siepmann, informa health care.

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