encapsulation_7 Flashcards
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
what is the purpose of having envelop air spray nozzle
the spray nozzle is extends spray into coating substrate bed and minimises local over-wetting
what does envelop air do in the spray nozzle
it prevents the spray from hitting the floor/surface, instead of dispersing, the spray is projected into the powder system
what is spray drying
widely used method to convert solutions, suspensions, or emulsions to dry powders, simple one-step process, highly efficient and versatile
advantage of spray drying
- reduce volume
- ease dosing, handling and transport
- improve chemical and biological stability
- defined shape and size
- porous and high specific surface
effect of spray drying suspensions
insoluble active solution of shell material
effect of spray drying solution
active and shell material as liquid
spray drying nozzle designs
- two fluid
- three fluid
- ultrasonic
- pressure
- rotary atomiser
spray prilling (congealing)
- for food and pharma products
- can be confined to smaller sizes
use of prilling
preparing meltable powders (lubricant), taste masking, controlled release products
types of capsules
- hard gelatin: cap and body, fit on inside the other
- soft gelatin: soft elastic gelatin capsule or softgel consist of a unit with a continuous gelatin shell surrounding a liquid fill material
issues with gelatin
- animal protein: religious/ animal disease/ green house gases
- moisture- sensitive
- properties may change with adsorbed constituents (aldehydes)
hard gelatin properties
- self locking mechanism
- from size 000 to 5 (0-4 is popular; smaller number bigger size)
- capsule fill weight = tapped density x capsule volume
- good fill depends on good flow properties of feed
hard capsule size to volume (0-4)
0: 0.67ml
1: 0.48ml
2: 0.37ml
3: 0.27ml
4: 0.2ml
non gelatin capsule
- hydroxypropylmethyl cellulose (HPMC)
- pullulan, water soluble polysaccharide
- HPM and carrageenan
- alginate
test for hard gelatin capsule
- assay
- uniformity of dosage units
- disintgration
- dissolution
different sizes of soft gelatin
- round
- oval
- oblong
- tube
advantages of soft gelatin capsules
- no compression stage, can contain poorly compressible drug
- liquid fill avoids powder flow and mixing problems
- avoid oxygen or moisture degradation of drug during long term storage, protected by gelatin shell
- for poorly water soluble drugs, in a liquid vehicle, emulsified in GIT as fine droplets
what should fill matrix of softgel capsules avoid
- emulsions, may crack
- Surfactants (high), affect gelatin integrity
- pH < 2.5, hydrolysis of gelatin
- pH > 7.5, tanning effect on gelatin, insolubility
- aldehydes, cross-linking, tanning effect
bioavailability from capsules
- dissolution from gelatin shell (puncturing), quickly disperses into intestinal liquid
- discharge of capsule content depends on flow of materials within
