Physical pharmacy Physical pharmacy


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Physical pharmacy

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Physical pharmacy Physical pharmacy

  2. 2. Matter: It’s what the world is made of.
  3. 3. Kinetic Theory of Matter Matter is made up of particles which are in continual random motion.
  4. 4. Binding Forces between Molecules The Three States of Matter: In order for molecules to exist in aggregates in gases, liquids and solids Intermolecular forces must exist 4
  5. 5. What is matter? Matter is anything that has mass and takes up • space.
  6. 6. STATES OF MATTER Based upon particle arrangement  Based upon energy of particles  Based upon distance between particles 
  7. 7. States of matter and intermolecular forces: • Gas: • Molecules in a gas attract each other, but the attractive forces are weak • compared with the thermal motion of the molecules so the molecules spread out evenly to fill the container enclosing them, however if a gas is cooled , the thermal motion will decrease and the gas will first liquify and then it will solidify. Liquids: • Liquids have sufficient attractive forces to stay in an open container but they • can still flow. Properties such as viscosity and its inverse fluidity are measures of the attractive forces in liquids. E.g., glycols are very viscous, while hexane flows very easily. • Solids: • Solids have enough attractive forces called crystal lattice energy that they • do not even flow, e.g., magnesium stearate is a lubricant needed to ease movement of drug powder in tableting machine.
  8. 8. Solids and the crystalline state A crystalline solid possesses rigid and long-range order. In a crystalline solid, atoms, molecules or ions occupy specific (predictable) positions. An amorphous solid does not possess a well-defined arrangement and long-range molecular order. A unit cell is the basic repeating structural unit of a crystalline solid. lattice point At lattice points : Atoms • Molecules Ions Unit Cell 8 Unit cells in 3 dimensions • •
  9. 9. The crystal lattice of sodium chloride NaCl Na 9 Cl
  10. 10. Seven Basic Unit Cells The various crystal forms are divide to basic 7 unit according to its symmetry iodine NaCl sucrose 10 Urea Iodoform Boric acid Beryl Be3Al2(SiO3)6
  11. 11. Types of Crystals 11.6
  12. 12. Characterization of crystalline materials:A- X- Ray Diffraction:It is photographed on sensitive plate arranged behind the crystal and by such method the structure of a crystal may be investigated. B- Melting point and Heat of fusion The freezing point or the melting point of a pure crystalline solid is strictly defined as the temperature at which the pure liquid and solid exist in equilibrium C- Polymorphism. Some substances, such as carbon or sulfur, my exist in more than one crystalline form and are said to be polymorphism.
  13. 13. X-Ray Diffraction X-ray are a form of electromagnetic radiation having a wavelength of the order of interatomic distanceoabout 1.5 A An Arrangement for Obtaining the X-ray Diffraction Pattern of a Crystal. 13
  14. 14. Polymorphism Some elemental substance such as C and S ,may exist in more than one crystalline form and are said to be allotropic, which is a special case of polymorphism Polymorphism are chemically identical, but they may have: Different stabilities • May spontaneously convert from metastable form at a temperature to a stabile form. Different melting point, XRD pattern and different solubility• Solubility and melting point are very important in pharmaceutical processes including dissolution and formulation. 14
  15. 15. Polymorphism and Industry/ Pharmaceutical Theobroma oil (caco butter)• Exist in 4 polymorphism Gamma form melt at 18 °C Alpha melt at 22°C Beta prime form melt at 28°C Stable beta form melt at 24.5 °C AIDS drug ritonavir• Was marked in dissolved formulation until a previously unknown , more stable and less soluble polymorph appeared Haloperiodal antipsychotic compound• Differences in the inter. Forces and hydrogen bonding cause the polymorphism 15
  16. 16. Polymorphism and Industry/ Pharmaceutical Cortisone acetate • Exist in at least 5 polymorph Heating, grinding , water and suspension in water are all factors that affect the interconversion of these different cortisone acetate forms. Tamoxifen antiestrogenic & antineoplastic drug• used for breast cancer B form (with H bonding is more stable) than form A 16
  17. 17. Amorphous Solids An amorphous solid does not possess a well-defined arrangement and long-range , and many synthetic plastics) molecular order.( Ex. Glass, pitch( Amorphous substances, as well as cubic crystal, are isotropic, that is, they exhibit similar properties in all direction. (iso= equal) The differ from crystalline solid in that they tend to flow and don’t have definite melting point. Crystals other than cubic are anisotropic, showing different characteristics (electronic conductance, refractive index(RX), crystal growth, rate of solubility ) in various direction along the crystal. (aniso= un equal) Amorphous or crystalline & therapeutic activity: The crystalline from of the antibiotic novobiocin acid is poorly absorbed and has no activity, where the amorphous form is readily absorbed and therapeutically active, due to different dissolution rate. 17
  18. 18. PHASE CHANGES Description of Phase Change Term for Phase Change Heat Movement During Phase Change Vaporization, Liquid to which includes Heat goes into the gas boiling and liquid as it vaporizes. evaporation Heat leaves the gas Gas to liquid Condensation as it condenses. Heat goes into the Solid to gas Sublimation solid as it sublimates.
  19. 19. Effect of Increase in Pressure on the Melting Point of Ice and the Boiling Point of Water P T 0.006 atm 19
  20. 20. Intermolecular Forces Intermolecular forces are attractive forces between molecules 1) ionic, 2) dipole - dipole, 3) H-bonding, 4) London forces, 5) covalent (network solids), 6) metallic. Intramolecular forces hold atoms together in a molecule (ionic, polar, non-polar). Intermolecular vs Intramolecular 41 kJ to vaporize 1 mole of water (inter) • 930 kJ to break all O-H bonds in 1 mole of water (intra) • “Measure” of intermolecular force Generally, intermolecular forces are much weaker than intramolecular forces. boiling point melting point Hvap Hfus 11.2 Hsub