what is encapsulation
process in which tiny particles or droplets are surrounded by a coating; filling formulation into a consumerable container
encapsulation technologies
- nano (1nm-1mcm)
- micro (1mcm -0.1mm)
- macro (0.1mm-1mm)
nano encapsulation
- imaging- phase contrast
- injectable drug delivery systems
- vaccine
micro encapsulation
- reasonable payload
- hold nutrients, enzymes, cells, etc
- offers protection, diffusion barrier
macro encapsulation
- high payload possible
- consistent production quality
- multi-particulate drug delivery system
encapsulation materials
particles, modified biopolymers, synthetic (co)polymers, low MW molecules
functional ingredient
- probiotics
- sensitive fatty acids
- antioxidants
- vitamins
- flavours, aroma’s colorants
- drug (like components)
release trigger
- pH
- mechanical stress
- enzymes
- ultrasound
- temperature
- ionic strength
- light
encapsulated technique
- emulsion based (pickering, self assembling, layer by layer)
- spray drying
- fluid bed coating
- extrusion
- coacervation
why encapsulation
provides isolation, entrapment, structuration, protection, or controlled release of a sensitive or reactive material (flavor, fragrance, bioactive) from the surrounding/ environment
advantage of encapsulation
- protection against moisture, oxygen and light
- prolong shelf life (stability)
- prevent premature release and pre-reaction
- mask undesirable taste, odor, and or color
- provide controlled release- rate, target, timed, delayed
- convert liq into solid (ease of handling)
- reduce inflammability
- improve safety and handling
liquid-based formulation (manipulation of pH, temperature, solubility, ionic interactions)
- well established method, batch process
- require skillful operator/operation
- often, contains gelatin (and other biopolymers can be used eg. casein, soy proteins, chitosan, starch, gums)
also use: carbonless paper, pesticides, fragrances, liquid, crystal, detergents, paint stabiliser, adhesive
what is coacervation
coacervation phase separation involves the separation of liquid phase of coating material from a polymeric solution and encapsulating the core particles by uniform polymeric layer
examples of coacervation phase
- gelatin-acacia
- gelatin-sodium alginate
emulsification
formation by water-organic solvent mixtures with surfactant (eg. sodium alginate solution in iso-octane + surfactants, hardened using calcium chloride)
application of emulsion based formulation
- protects drug from environment
- mask unpleasant taste and odor
- reduce drug volatility
- reduced gastric irritation by drug
- controls drug release
- separates incompatible components
- produces chemoembolisation agents
- produces microbioreactors
coating of cores containing active ingredients for
- modification of drug release (delayed sustained release)
2. protection of drug (taste making, moisture/gas barrier, UV protection, add color)
coated dosage form systems
- coated particle: popular in taste masking, stability enhance
- coated pellet: multi-particulate drug delivery system; multi-unit pellet system (MUPS) tablets
- coated tablet: decorative and identification; enteric coated; sustained release coated, osmotic pump
- coated capsule: not common, enteric release, prolong release
reason for control release
occurs in a planned predictable and slower-than-normal method, to deliver drugs at specific planned and controlled rate
advantages of control release system
- extended daytime and night time activity of drug
- potential for reduced incidence of side effects
- reduced dosage freq
- increase pt compliance
- potential low daily cost of pt (fewer dosage units)
coating processes of pharmaceuticals
- compression- utilises a special tablet press, with capability of multi-layer compression
- pan coating - popular and well established method to coat tablet
- air suspension - air suspension wurster coating is used for coating small particles such as pellets
- spray coating- spray dryers are used to convert liquid feeds to dry powders, can be used for coating
- melt coating- niche technology, by hot melting extrusion or spray congealing (priling)
design strategies of sustained drug release pellet
- nonpareils are used as cores to be layered with drug, then overcoated with diffusion barrier polymer coat
- drug-loaded pellets are prepared by extrusion-spheronisation, then overcoat with a diffusion barrier polymer coat
what are nonpareils beads made of
sugar/ microcrystalline cellulose
what are drug layer consist of
polymer and drug
