Particulate DD

• Problems with traditional delivery systems

  1. Reduced bioavailability due to physiological degradation
  2. Potential toxic levels of administration
  3. Excess dosing (increasing costs)
  4. Compliance issues
• WHY do we need novel DD systems?

  1. Prevent physiological degradation
  2. Prolong circulation time
  3. control release rates
  4. Reduce frequency of dosing to increase patient compliance
• How can encapsulation help?

  1. Isolate from its surroundings (protection)
  2. Improve bioavailability
  3. Targeting
  4. Controlled release
• Liposomes

  • An artificial microscopic surfactant vesicle
  • Aqueous core enclosed in one/more phospholipid layers
  • Can protect drugs from degradation in vivo
  • Non-toxic
  • Used to convey vaccines, drugs, enzymes, or other substances to target cells or organs
  • Controlled Release
  • Can target and deliver drugs to required site of action.
• Advantages of liposomes

  • Hydrophobic drugs (bilayer)and hydrophilic drugs (core)
  • Targeting: Attachment of antibodies on the surface
  • Decrease toxicity: off-target effect
  • Tailorable: Charge, size, surface characteristics
• Disadvantages of liposomes:

  • cost
  • scale up difficult
  • stability (physical and chemical, lyophilisation)
  • Often need modification (costly)
• Microspheres


  Can load drug within particles with the potential of offering protection.

  Offer controllable release kinetics by manipulating polymer composition.

  Previously demonstrated safety profile with several polymer systems.
• Formulation of microspheres

  • w/o/w double emulsion solvent evaporation
  • vortex mix: aqueous component containing drug is dispersed in organic solvent containing polymer
  • homogenize: primary emulsion dispersed into aqueous phase
  • solvent removal: leaves behind microspheres