Colloidal Dispersions Specific Aims (PDF)

[Colloidal dispersions -- specific aims] 1\. Be able to define dispersion systems and colloidal systems. What is the typical size range of colloidal particles? Do some suspensions and emulsions contain a range of particle size such that the smaller particles lie within the colloidal range, whereas...

[Colloidal dispersions -- specific aims] 1\. Be able to define dispersion systems and colloidal systems. What is the typical size range of colloidal particles? Do some suspensions and emulsions contain a range of particle size such that the smaller particles lie within the colloidal range, whereas the larger ones are classified as coarse particles? 2\. Be able to explain the effects of shape and size of colloidal particles on their properties. Is the surface area of colloidal particles large compared with the surface area of an equal volume of larger particles? 3\. Be able to define and describe major characteristics of lyophilic, lyophobic, and association colloids. Which type(s) of colloids interact(s) to an appreciable extent, and has/have affinity toward the dispersion medium? Which type(s) of colloids is/are formed spontaneously? Which type(s) of colloids is/are covered with a solvent sheath? 4\. Be able to describe for lyophilic colloids whether a material that forms such a system in one liquid (e.g., water) will necessarily do so in another liquid (e.g., benzene). Are lyophilic colloids always formed in aqueous dispersion media? In which dispersion medium are hydrophilic and hydrophobic colloids formed? Can insoluble but extensively solvated particles dispersed in a liquid medium that has a high affinity or attraction to them form hydrophilic colloids? Do such particles dissolve or break down into individual molecules or ions? 5\. Be able to describe hydrophilic colloids (hydrocolloids), including the main types of materials that can form them. For water soluble polymers acting as hydrophilic colloids is each particle made from a single molecule? 6\. Be able to describe for lyophobic colloids whether their preparation requires various physical and chemical considerations for the reduction of particle size to the colloid range. Are particles of hydrophobic colloids hydrated by their dispersion medium? Which type of colloids do intravenous fat emulsions form? 7\. Be able to describe the (3) major types of association colloids, and on which type of materials are they based on? 8\. Be able to describe micelles and their main characteristics, including size and how many monomers does each micelle contain. Do micelles and amphiphiles that exist separately in a low concentration at a liquid medium have colloidal or subcolloidal dimensions? What would be the typical environment in the core of micelles formed in an aqueous dispersion medium? Are micelles static aggregates? In an aqueous dispersion medium, where will amphiphiles go first, to the air-water interface or to the bulk phase? 9\. Be able to describe the Critical Micelle Concentration (CMC). In concentrations above the CMC, where will additional amphiphile added to the system go? Is the surface tension substantially reduced above or below the CMC? Is the solubility of water-insoluble solubilizate increasing above or below the CMC? 10\. Be able to describe the main pharmaceutical applications of colloidal dispersion systems. Do some of the biotechnology drugs form colloidal dispersions? 11\. Be able to define solubilization. To which systems does this term usually refer to? In which part of the micelle will nonpolar, slightly polar, and an amphipathic solubilizate reside? Is the site of solubilization within the micelle closely related to the chemical nature of the solubilizate? What may be the result of using excessive amounts of surfactants in a micelle system? If the system has an insufficient concentration of surfactants so that the number of micelles formed is small, how may this affect the solubilizate? 12\. Be able to describe for Adult Infuvite Multiple Vitamins for Infusion which vitamins are most likely to be solubilized, and which inactive ingredient is responsible for solubilization? 13\. Be able to describe major characteristics, advantages and disadvantages of microemulsions. Typically how many surfactants are required in a microemulsion formulation to lower the interfacial tension? Is the amount of surfactants in microemulsions small or large? Are microemulsions formed spontaneously? Are they more appropriate as carriers of hydrophilic or lipophilic drugs? Is their preparation more simple or difficult in comparison to the preparation of coarse emulsions? 14\. Be able to define liposomes and to describe different types of liposomes and what are the major differences between them, including advantages and disadvantages. Are liposomes vesicles consisting an aqueous core surrounded by concentrically arranged monolayer or bilayer membranes? Which type of materials are the main components of liposomes? What is the possible contribution of cholesterol to the liposome structure? Can liposomes accommodate water-soluble drugs, lipid-soluble drugs, or both? In which regions of the liposomes will drugs reside? 15\. Be able to describe the factors that determine whether a molecule dispersed in an aqueous system will form micelles or liposomes. Which factor is the most important in determining whether micelles or liposomes will be formed? 16\. Be able to describe drug release from liposomes. What is a major factor needed for drug release? 17\. Be able to describe the fate of liposomes after intravenous injection. What is the typical half-life of liposomes? What is the effect of uptake by the Mononuclear Phagocyte System (MPS) on the fate of liposomes? Is the uptake by the MPS always undesirable? 18\. Be able to describe stealth liposomes and their effect on MPS uptake of liposomes. What is the main characteristic of stealth liposomes? Which specific polymers are most commonly used for grafting or coating liposome surfaces to design stealth liposomes, and are these polymers water soluble or water insoluble? What would be an example of the half-life of a product that evades the MPS? 19\. Be able to describe advantages and disadvantages, including the main disadvantage, of liposomes. Are drugs encapsulated in liposomes more or less susceptible to degradation? 20\. Be able to describe the mechanism that underpins the targeting of liposomes to tumor cells. 21\. Be able to define nanotechnology and nanoparticles. What are the (3) main types of nanoparticles? 22\. Be able to describe Abraxane. Can binding of albumin to a drug with low solubility such as paclitaxel promote targeting to tumor cells, and if so then what are the mechanisms underlying this phenomenon?