Pharmaceutics: Emulsions and Emulsifiers
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Questions and Answers

What is the process of deflocculation?

  • Particles sticking together
  • Particles forming a rigid interfacial film
  • Particles separating (correct)
  • Particles forming an electric double layer

    • What is the effect of reducing interfacial tension in stabilization?

  • Forming a lyophilic colloid
  • Forming a rigid interfacial film (correct)
  • Increasing the viscosity of the solution
  • Increasing the electric double layer

    • What is the type of emulsifier that is represented by Na lauryl SO4?

  • Amphiphilic emulsifier
  • Anionic emulsifier (correct)
  • Non-ionic emulsifier
  • Cationic emulsifier

    • What is the characteristic of a lyophilic colloid?

    <p>It is stable and interacts well with the dispersion medium</p> Signup and view all the answers

    What is the method of preparing a lyophobic colloid?

    <p>Using insoluble particles</p> Signup and view all the answers

    What is the term for the process of taking up a certain liquid amount without an increase in gel volume?

    <p>Imbibition</p> Signup and view all the answers

    What is the type of cream that is represented by Cetrimide?

    <p>Cationic cream</p> Signup and view all the answers

    What type of colloids are dispersed molecules soluble in the medium?

    <p>Lyophilic</p> Signup and view all the answers

    What is the primary advantage of microspheres in pharmaceutical formulations?

    <p>Delayed release</p> Signup and view all the answers

    What is the primary function of viscosity inducing agents in pharmaceutical formulations?

    <p>To thicken or gel the formulation</p> Signup and view all the answers

    What is the primary application of liposomes in pharmaceuticals?

    <p>Targeted drug delivery</p> Signup and view all the answers

    What is the consideration for dosage forms in terms of the patient?

    <p>Age and condition of the patient</p> Signup and view all the answers

    What is the primary difference between single-phase and two-phase gels?

    <p>Boundaries between particles</p> Signup and view all the answers

    What is the effect of pH on Carbopol dispersions?

    <p>Remains stable</p> Signup and view all the answers

    What is the primary advantage of pegylated nanoparticles?

    <p>Increased solubility</p> Signup and view all the answers

    What is the primary goal of desirables properties of suspensions?

    <p>Uniform dosage and easy redispersion</p> Signup and view all the answers

    What is syneresis in the context of pharmaceuticals?

    <p>Gel contraction caused by interaction of particles of the dispersed phase</p> Signup and view all the answers

    What is the primary advantage of using hydrogels in wound healing and dressing?

    <p>Their ability to absorb and debride necrotic and fibrotic tissues</p> Signup and view all the answers

    What is the primary motivation behind the formulation of suspensions in pharmaceuticals?

    <p>To facilitate easy swallowing and dosage separation</p> Signup and view all the answers

    What is the DLVO theory related to in the context of pharmaceuticals?

    <p>The energy of attraction and repulsion between particles</p> Signup and view all the answers

    What is a major advantage of using emulsions in pharmaceuticals?

    <p>They can improve the absorption of poorly soluble drugs</p> Signup and view all the answers

    What is the purpose of sterilization methods in pharmaceuticals?

    <p>To ensure the drug is free from microbial contamination</p> Signup and view all the answers

    What is the Sterility Assurance Level (SAL) for topical pharmaceuticals?

    <p>1 in 1000</p> Signup and view all the answers

    What is the primary purpose of dermatological recommendations in pharmaceuticals?

    <p>To ensure drug safety</p> Signup and view all the answers

    Study Notes

    Deflocculation and Stabilisation

    • Deflocculation: particles separate
    • Stabilisation effect: reducing interfacial tension, forming a rigid interfacial film, and formation of an electric double layer

    Emulsifiers

    • HLB (Hydrophilic-Lipophilic Balance) equation: measures the balance between hydrophilic and lipophilic parts of an emulsifier
    • Types of emulsifiers:
      • Anionic: Na lauryl SO4, Ca Oleate, Cetostearyl alc.
      • Cationic: Cetrimide
      • Non-ionic: Tween 80, Glyc. Monostearate, Span 60, Cetomacrogol 1000

    Ointment Bases

    • Types of ointment bases:
      • Hydrocarbon-based
      • Oleaginous
      • Absorption bases
      • Water-soluble bases
      • Water-miscible bases
      • Removable bases

    Creams

    • Types of creams:
      • Aqueous creams (anionic)
      • Cetrimide creams (cationic)
      • Sorbolene and cetomacrogol creams (non-ionic)

    Colloids

    • Properties of colloids:
      • Lyophilic: stable, interacts well with dispersion medium, and forms with relative ease
      • Lyophobic: opposite to lyophilic, uses insoluble particles
      • Association: dispersed phase are aggregates of small molecules
    • Examples of colloids:
      • Gelatin, acacia, albumin, and insulin in water (lyophilic)
      • Au, Ag, S, and AgI (lyophobic)

    Colloid Preparation Methods

    • Dispersion: particles ground in solvent mill, subjected to high heat, and forced through a narrow gap between 2 rotating surfaces to tear particles apart
    • Chemical methods:
      • Dissolution and precipitation
      • Condensation
    • Emulsion: emulsifier is added to create a homogenized solution

    Imbibition and Syneresis

    • Imbibition: takes up a certain liquid amount without an increase in gel volume
    • Syneresis: gel contraction caused by interaction of particles of the dispersed phase

    Hydrogels

    • Provides absorption, desloughing, and debriding capacities to necrotic and fibrotic tissues
    • Fills the wound cavity and protects granulating tissue

    Suspensions

    • Coarse dispersions of fine, large, and insoluble particles
    • Formulated to allow for easy swallowing, dosage separation, palatability, stability, and prolonged action/relief

    DLVO Theory

    • Related to energy of attraction (van der Waals forces) and repulsion (electric double layer)
    • The second minimum is beneficial as particles have a limited overall attraction to each other and behave as floccules (loose aggregates of individual particles)

    Emulsions

    • Advantages: can be administered without swallowing difficulty, disguises tastes or smells of oils or oil-based drugs, and improves absorption of poorly soluble drugs
    • Disadvantages: thermodynamically unstable, difficult to formulate and manufacture

    Dermatological Recommendations

    • Clean treatment area, remove any matting hair, spread a thin and even layer of medication, and leave
    • Do not cover unless absolutely necessary
    • Remind patients of drug safety

    Sterilisation Methods

    • Heat: steam or dry heat
    • Gas: ethylene oxide and inert gas
    • Radiation: gamma or beta radiation
    • Filtration: physically removed from drug

    Sterility Assurance Levels (SAL)

    • Probability of 1 unit being non-sterile
    • Topical: 1 in 1000
    • Parenterals: 1 in 10^6

    Viscosity Inducing Agents

    • Gelatin, Agar, alginic acid, guar gum, dextrin, and xanthan gum

    Colloidal Drug Delivery Systems

    • Micelles, microemulsions, liposomes, parenteral emulsions, microspheres, nanoparticles, and drug-polymer conjugates

    Determining Colloidal Particle Size

    • Hydrodynamic chromatography
    • Light scattering
    • Electron microscopy
    • Tyndall effect

    Liposomes

    • Drug delivery vehicle with a lipid bilayer and a hydrophilic, aqueous area
    • Used for enhancing drug targeting and passive or active targeting

    Microspheres

    • Spherical particles with a diameter in micrometres
    • Porous and allows a delayed release due to its structure

    Nanoparticles

    • Prepared with polymers and lipids as well as proteins
    • Pegylated: coated with PEG to increase solubility

    Gels

    • Single-phase gels: no clear boundary between particles and more restricted movement
    • Two-phase gels: individual particles that are cross-linked and have limited movement
    • Hydrogels: in-organic
    • Organogels: hydrophobic

    Effect of pH on Dispersions

    • Carbopol: can form acidic solution, causing neutralisation and precipitation
    • Cellulose derivatives: wide pH range
    • Bentonite magma: addition of acid reduces pH, causing instability and reducing absorption of water

    Desirable Properties of Suspensions

    • Non-rapid settling
    • Easy redispersion
    • Free-flow
    • Uniform dosage after shaken
    • Particle size constant
    • Acceptable to patient

    Flocculation vs Deflocculation

    • Flocculation: aggregates formed
    • Can occur by reducing zeta potential
    • Deflocculation: particles separate

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    Description

    This quiz covers the concepts of deflocculation and stabilisation, and the types of emulsifiers used in pharmaceuticals, including their characteristics and HLB balance.

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