dissolution 1

• What is the intrinsic dissolution rate?

  Rate of transfer from solid to dispersion
• What is the first step in the dissolution process?

  Solute removal from the crystal
• What controls the rate of absorption in dissolution?

  The static boundary layer of liquid
• What does the Noyes-Whitney equation govern?

  Dissolution process
• What does $dm/dt$ represent in the Noyes-Whitney equation?


  Rate of solution
• How does surface area affect the rate of solution?

  Increased surface area increases the rate
• What is the effect of temperature on dissolution rates?

  Higher temperature increases the rate
• What is defined as rapid dissolution for a dosage form?

  More than 85% dissolved in 30 minutes
• What are sink conditions in dissolution?

  Solute removed faster than solution
• What is a limitation of the Noyes-Whitney equation?

  Assumes constant particle size during dissolution
• What physiological factors influence in vivo dissolution?

  • GI fluid volume
  • Fasted or fed state
  • Surfactant concentration
  • Residence time and mixing
  • Disease state
  • Diet
• What physicochemical factors influence in vivo dissolution?

  • Solubility
  • Log P
  • Melting point
  • Physical form
  • pKa
  • Particle size
  • Wettability
• What formulation factors influence in vivo dissolution?

  • Dosage form type
  • Particle size
  • Release properties
  • Excipient composition
  • Surfactants
  • Binders
  • Disintegrants
• Why is in vitro dissolution testing important?

  • Predicts in vivo behavior
  • New innovator product assessment
  • Bioequivalence testing
  • Regulatory approval
  • Quality control
• What is the fluid volume in the stomach for drug dissolution?

  118 mL
• What is the fluid volume in the small intestine for drug dissolution?

  212 mL
• What is the fluid volume in the large intestine for drug dissolution?

  187 mL
• What is the fluid volume in the rectum for drug dissolution?

  2-3 mL
• What is the fluid volume in the oral cavity for drug dissolution?

  0.9-1.1 mL
• How does particle size affect dissolution?

  Smaller particles increase dissolution rate
• What role do surfactants play in dissolution?

  They enhance solubility and dispersion
• What is the significance of the melting point in dissolution?

  It affects solubility and dissolution rate
• How does the presence of other compounds influence dissolution?

  It can alter solubility and absorption
• What is the effect of viscosity on dissolution rates?

  Higher viscosity decreases the rate
• What is the relationship between agitation and dissolution rate?

  Increased agitation increases the rate
• What is the role of binders in formulation factors?

  They help hold the formulation together
• What is the role of disintegrants in formulation factors?

  They promote the breakdown of dosage forms
• What is the role of solubility enhancers in formulation factors?

  They increase the solubility of the drug
• What is the role of granulating agents in formulation factors?

  They help form granules for uniformity