Material Science

• What is the primary focus of material science in solid state properties?

  Understanding crystal structure
• What is polymorphism in the context of pharmaceuticals?

  Formation of different polymorphs affecting drug properties
• What are the advantages of using amorphous materials in pharmaceuticals?

  They offer unique properties but have challenges
• What are crystal hydrates?

  Crystals containing water molecules
• What does modified release refer to?

  Altering timing and rate of drug release
• What is controlled release in drug formulation?

  Maintaining consistent drug concentration over time
• Why is solid state important for most drugs?

  Higher stability, precision, and easier handling
• What are the associated problems with solid state drugs?

  Physical changes, solubility, and bioavailability issues
• What defines a crystalline solid?

  Molecules packed in a defined long order
• What is a characteristic of amorphous solids?

  No defined order in molecular packing
• Why do crystalline solids have a melting point?

  Atoms arranged in a repeating pattern require energy
• What happens to the shelf life of amorphous drugs?

  They change form from less stable states
• What is the unit cell in crystal structure?

  A repeating unit in the crystal lattice
• What forces hold molecules in a crystal lattice?

  Intermolecular forces like hydrogen bonding
• What is crystal habit?

  The external shape of a crystal
• What is polymorphism in drugs?

  Same molecule existing in different crystalline forms
• What is monotropic polymorphism?

  Only one stable form exists regardless of temperature
• How does the stability of monotropic forms affect solubility?

  Metastable forms are more soluble than stable ones
• What is enantiotropic polymorphism?

  Different forms may be stable under varying conditions
• What can cause polymorphic transitions?

  Manipulating crystallisation conditions like temperature
• What are the pharmaceutical implications of polymorphism?

  Different polymorphs affect melting points and solubility
• How does polymorphism affect bioavailability?

  Less stable forms have better dissolution rates
• What is a solvate?

  Solvent trapped in the crystal lattice
• What is a hydrate in crystal formation?

  Water molecules present in the crystal structure
• What is the implication of hydrate formation on drug properties?

  Hydrates may have different melting points and dissolution rates
• What characterises amorphous materials?

  No repeating long order in molecular structure
• What is the glass transition temperature (Tg)?

  Temperature where material changes from glassy to rubbery
• How do solid dispersion systems improve bioavailability?

  They force solid into another solid for better solubility
• What is the process of amorphous formation through rapid cooling?

  Cooling too fast to allow crystallisation
• What is the role of anti-solvent in amorphous formation?

  It influences shape and crystallisation ability
• What is the significance of sublimation in amorphous systems?

  It allows water to evaporate from the material
• Why do amorphous systems have more rapid dissolution?

  No lattice energy to overcome in dissolution
• What is the impact of amorphous systems on stability?

  They will eventually recrystallise on storage
• How do solid dispersions improve drug solubility?

  They prevent recrystallisation and provide stability
• What techniques are used to determine solid states?

  X-ray powder diffraction and differential scanning calorimetry
• What are the characteristics of crystalline and amorphous solids?

  Crystalline:

  • Defined long order in molecular packing
  • Has a melting point
  • Most stable state

  
  

  Amorphous:

  • No defined order in molecular packing
  • No melting point
  • Poor stability and interacts with the environment
• What are the types of polymorphism and their characteristics?

  Monotropic:

  • One stable form regardless of temperature
  • Metastable forms convert to stable form

  
  

  Enantiotropic:

  • Different forms stable under varying conditions
  • Stability depends on temperature and pressure
• What are the implications of polymorphism on drug properties?

  • Different melting points
  • Varying solubilities
  • Different dissolution rates and bioavailability
  • Impact on processing and stability
• What are the methods for amorphous formation?

  • Rapid cooling from the melt
  • Mechanical activation (milling)
  • Precipitation from solution
  • Use of anti-solvent/freeze drying
• What are the roles of polymers in amorphous stabilization?

  • Trapping drugs in glass solutions
  • Preventing recrystallisation
  • Providing physical barriers