MICROENCAPSULATION
Definition:It is the process by which individual particles or
droplets of solid or liquid material (the core) are surrounded or
coated with a continuous film of polymeric material (the shell) to
produce capsules in the micrometer to millimeter range, known as
microcapsules.
OrMicroencapsulation may be defined as the process of
surrounding or enveloping one substance within another substance on
a very small scale, yielding capsules ranging from less than one
micron to several hundred microns in size.
Features of Microcapsule:Microencapsulation is the packaging of
small droplets of liquid or particles with a thin film.
Size:Typically, the lowest particle size of microcapsules is 1m
and the largest size is 1mm.
Composition:Microcapsules consist of a core and a wall (or
shell).
Shape:The configuration of the core can be a spherical or
irregular particle, liquid-phase suspended solid, solid matrix,
dispersed solid and aggregates of solids or liquid forms.
Classification:Microcapsules can be classified on three basic
categories according to their morphology as follows,1.
Mononuclear:Mononuclear (core-shell) microcapsules contain the
shell around the core.2. Polynuclear:Polynuclear capsules have many
cores enclosed within the shell.3. Matrix types:In matrix
encapsulation, the core material is distributed homogeneously into
the shell material.
In addition to these three basic morphologies, microcapsules can
also be mononuclear with multiple shells, or they may form clusters
of microcapsules.
Generally microparticles are divided in to two components;a)
Core material.b) Coat or wall or shell material.
Core materials:The material to be coated. It may be liquid or
solid or gas. Liquid core may be dissolved or dispersed
material.
Composition of core material:
Drug or active constituent.
Coating materials:
Gums: Gum arabic, sodium alginate, carageenan. Carbohydrates:
Starch, dextran, sucrose Celluloses: Carboxymethylcellulose,
methycellulose. Lipids: Bees wax, stearic acid, phospholipids.
Proteins: Gelatin, albumin.
REASONS FOR ENCAPSULATION:
This technique has been widely used for masking the organoleptic
properties like taste and odor of many drugs and thus improves
patient compliance e.g. Paracetamol, nitrofurantoine for masking
the bitter taste. By using microencapsulation techniques the liquid
drugs can be converted in a free flowing powder. The drugs can be
protected by microencapsulation which is sensitive to moisture
light and oxygen, such as nifedipine is protected from photo
instability. Microencapsulation technique also helpful to prevent
the incompatibility between drugs The drugs which are volatile in
nature may vaporize at room temperature like Aspirin and peppermint
oil can be prevented by microencapsulation.
Microencapsulation has also been employed to change the site of
absorption. This application has been useful for those drugs which
have the toxicity at lower pH.
1. Core protection:The core must be isolated from its
surroundings, as1. To protect reactive substances from the
environment,2. To convert liquid active components into a dry solid
system,3. To separate incompatible components for functional
reasons,
2. Controlled release of drug:1. For targeted drug delivery2.
For delayed release of drug3. For prolong release of drug4. To
increase bioavailability of drug
TECHNIQUES TO PREPARE:
These depends on
1.0 DRUG FACTORS:
Physical properties Chemical properties Biological activity
Nature of drug Stability of drug
2.0 PRODUCTION REQUIREMENT:
Entrapment efficiency Percentage yield
PHYSICAL METHODS
Spray drying Spray congealing Air suspension Fluid bed coating
Pan coating Centrifugal extrusion Vibration nozzle Multi orifice
centrifugation process Spinning disk
SPRAY DRYING AND SPRAY CONGEALINGSPRAY DRYING:Microencapsulation
by spray-drying is a low-cost commercial process which is mostly
used for the encapsulation of fragrances, oils and flavors.Steps:1.
Core particles are dispersed in a polymer solution and sprayed into
a hot chamber.1. The shell material solidifies onto the core
particles as the solvent evaporates.The microcapsules obtained are
of polynuclear or matrix type.
SPRAY-CONGEALING:- This technique can be accomplished with spray
drying equipment when the protective coating is applied as a
melt.
1- The core material is dispersed in a coating material melt.2-
Coating solidification (and microencapsulation) is accomplished by
spraying the hot mixture into a cool air stream.- e.g.
microencapsulation of vitamins with digestible waxes for taste
masking.
AIR-SUSPENSION COATING
Microencapsulation by air suspension technique consist of the
dispersing of solid, particulate core materials in a supporting air
stream and the spray coating on the air suspended particles. Within
the coating chamber, particles are suspended on an upward moving
airstream.During each pass through the coating zone, the core
material receives an increment of coating material. The cyclic
process is repeated, perhaps several hundred times during
processing, depending on the purpose of microencapsulation the
coating thickness desired or whether the core material particles
are thoroughly encapsulated.
FLUID BED COATINGFluid bed coating is restricted to
encapsulation of solid core materials, including liquids absorbed
into porous solids. Solid particles to be encapsulated are
suspended on a jet of air and then covered by a spray of liquid
coating material. The capsules are then moved to an area where
their shells are solidified by cooling or solvent vaporization. The
process of suspending, spraying, and cooling is repeated until the
capsules' walls are of the desired thickness.
Different types of fluid-bed coaters include top spray, bottom
spray, and tangential spray(a) Top spray(b) Bottom spray(c)
Tangential spray.In the top spray system the coating material is
sprayed downwards on to the fluid bed such that as the solid or
porous particles move to the coating region they become
encapsulated. The bottom spray is also known as Wursters coater.
This technique uses a coating chamber that has a cylindrical nozzle
and a perforated bottom plate. The cylindrical nozzle is used for
spraying the coating material. As the particles move upwards
through the perforated bottom plate and pass the nozzle area, they
are encapsulated by the coating material.The tangential spray
consists of a rotating disc at the bottom of the coating chamber,
with the same diameter as the chamber. During the process the disc
is raised to create a gap between the edge of the chamber and the
disc. The tangential nozzle is placedAbove the rotating disc
through which the coating material is released. The particles move
through the gap into the spraying zone and are encapsulated. As
they travel a minimum distance there is a higher yield of
encapsulated particles.
SPINNING DISK
Suspensions of core particles in liquid shell material are
poured into a rotating disc. Due to the spinning action of the
disc, the core particles become coated with the shell material. The
coated particles are then cast from the edge of the disc by
centrifugal force. After that the shell material is solidified by
external means (usually cooling). This technology is rapid,
cost-effective, and relatively simple and has high production
efficiencies.
PAN COATING
When coating is liquid?
Coating is applied as a coating solution or atomized spray to
the dried solid core particles in the coating pan. To remove the
coating solvent warm air is supplied to the coated materials while
coatings are applied in the coating pan.On some cases the solvent
is removed by drying in the oven.
When coating is solid?
1- Solid particles are mixed with a dry coating material. 2- The
temperature is raised so that the coating material melts and
encloses the core particles, and then is solidified by cooling.
CENTRIFUGAL EXTRUSIONAs shown in Figure The simple extrusion
method utnizes a device consisting of two concentric tubes
containing aligned fluid nozzles. The liquid material to be coated
is extruded through the nozzle of the inner tube into the coating
fluid contained in the outer tube. Initially. The fluid extrudes as
a rod surrounded by the coating fluid, but the rod ultimately
breaks up into droplets which are then immersed in the coating
fluid. As the extruded droplets pass through the nozzle orifice of
the outer tube. The coating fluid forms a surface coat which
encases the extruded particle.
Spherically shaped particles are formed by the surface tension
of the liquid. By suitable means the formed coat is converted to a
more rigid structure. Hardening baths are usually employed for this
purpose.
VIBRATIONAL NOZZLE:It works under the same principle as the
extrusion only difference is that an additional vibrational nozzle
is used for encapsulation and flow of fluid is
laminar.Matrix-encapsulation can be done using a laminar flow
through a nozzle and an additional vibration of the nozzle or the
liquid.
MULTI ORIFICE-CENTRIFUGAL PROCESS: Microencapsulation by the
multi orifice-centrifugal process is the mechanical process in
which the centrifugal force is applied to throw a core material
particle through an enveloping microencapsulation membrane.
The factors affect the Process include the rotational speed of
the cylinder, the flow rate of the coating and core materials and
the concentration, viscosity and surface tension of the core
material. It consists of a cylinder containing three
circumferential grooves (coating material inlet)Core material
inletCounter rotating discRotating cylinder
Process: Coating material is introduced through the inlet
grooves. The coating material under the influence of
centifugational force imparted by cylinder rotation flows outward
along the immediate groove and form film on orifice. The counter
rotating disc disperses the core material towards the orifice. Core
material encounters the coating material membrane at orifice and
encapsulation occurs.
CHEMICAL METHODS
1. SOLVENT EVAPORATION METHOD
Process Step I (Dispersion of Drug in Polymer Solution)In this
process microcapsule coating (polymer) is dissolved in a volatile
solvent, which is immiscible with the liquid manufacturing vehicle
phase.Methylene chloride is a preferred solvent because of its high
volatility (boiling point 41C). Mixed solvents can also be used.
The mixtures used so far tend to contain a water-immiscible solvent
(e.g., CH2CI2) and a water-miscible solvent (e.g., acetone). The
water immiscible solvent is the predominant component of the
mixture. Once the desired coating polymer is dissolved in the
organic solvent, the drug to be encapsulated is added to this
solution. The drug agent may be a solid (crystalline or amorphous)
or a nonvolatile liquid. The added drug may completely dissolve in
the polymer solution or it may be completely insoluble and simply
form a dispersion, suspension, or suspension-emulsion.
Step II (Emulsification)To obtain the microcapsule of
appropriate size the core and coating material mixture is dispersed
in the liquid manufacturing vehicle phase (water) with
agitation.The drug/polymer/solvent mixture (i.e., the oil phase) is
emulsified in water to form an oil-in-water emulsion. In order to
aid emulsification, a surfactant (PVA) is normally dissolved in the
water phase before the oil-in-water emulsion is formed. Step III
(Evaporation)Evaporation is carried out by heating. Step IV
(Separation)Once solvent evaporation appears to be complete, the
capsules are separated from the suspending medium by filtration,
washed, and dried.
If the core material is dispersed in the polymer solution the
polymer shrinks around the core. And if core material is dissolved
in the coating solution matrix type microcapsules are formed.
POLYMERIZATION:
Microencapsulation by polymerization involved reaction of
monomeric units located at interface between a core material
substance and continuous phase in which the core material is
dispersed. In polymerization a liquid or gaseous phase is used as
continuous or core material and as a result the polymerization
reaction occurs at a liquid-liquid, solid-liquid, Liquid-gas, or
solid-gas interface.
1. Interfacial polymerization (IFP)In this technique the capsule
shell will be formed on the surface of the droplet or particle by
polymerization of the reactive monomers. The substances used are
multifunctional monomers.Generally used monomers include
Multifunctional isocyanates Multifunctional acid chlorides These
will be used either individually or in combination.Process The
multifunctional monomer (acid chlorides immiscible with water)
dissolved in liquid core material and it will be dispersed in
aqueous phase containing dispersing agent. A co reactant
multifunctional amine will be added to the mixture. The
polymerization depends on the fact that acid halides are water
insoluble and diamines have partition coefficient toward the water
immiscible organic phase and diffuse towards it and it results in
rapid polymerization at interface and generation of capsule shell
takes place. A poly urea shell will be formed when isocyanate
reacts with amine A polynylon or polyamide shell will be formed
when acid chloride reacts with amine.
2. In situ polymerization (ISP)In this process no reactive
agents are added to the core material, polymerization occurs
exclusively in the continuous phase. Initially a low molecular
weight pre polymer will be formed, as time goes on the pre polymer
grows in size, it deposits on the surface of the dispersed core
material there by generating a solid capsule shell.
3.0 PHYSICOCHEMICAL METHOD:
COESERVATIONA coacervate is a tiny spherical droplet of assorted
organic molecules (specifically, lipid molecules) which is held
together by hydrophobic forces from a surrounding liquid. Their
name derives from the Latin coacervare, meaning to assemble
together or cluster.
PROCESSThe general outline of the processes consists of three
steps carried under continuous agitation:Step 1: Formation of three
immiscible chemical phasesThe immiscible chemical phases are (i) A
liquid manufacturing vehicle phase (ii) A core material phase (iii)
A coating material phaseTo form the three phases, the core material
is dispersed in a solution of the coating polymer, the solvent for
the polymer being the liquid manufacturing vehicle phase. The
coating material phase, an immiscible polymer in a liquid state, is
formed by utilizing one of the methods of phase separation
coacervation, that is, By changing the temperature of the polymer
solution By adding incompatible polymer to the polymer solution By
inducing a polymer-polymer interaction
Step 2: Depositing the liquid polymer coating upon the core
materialThis is accomplished by controlled, physical mixing of the
coating material (while liquid) and the core material in the
manufacturing vehicle. Deposition of the liquid polymer coating
around the core material occurs if the polymer is adsorbed at the
interface formed between the core material and the liquid vehicle
phase, and this adsorption phenomenon is a prerequisite to
effective coating. The continued deposition of the coating material
is promoted by a reduction in the total free interfacial energy of
the system, brought about by the decrease of the coating material
surface area during coalescence of the liquid polymer droplets.Step
3: Rigidizing the coatingThis is usually done by Thermal Technique
Cross linking Technique Desolvation Technique, to form a
self-sustaining microcapsule.
1. TEMPERATURE CHANGE METHOD:Change in temperature causes
separation of coating material from the solventUseful when the
solubility of the material depend on temperature E.g. Coating mat.:
Ethyl cellulose in cyclohexane (EC is insoluble in Cyclohexane at
room temp.) Core Material: N-Acetyl P-Amino PhenolThe EC is
insoluble in cyclohexane at room temperature but is soluble at
elevated temperatures. The mixture is heated to the boiling point
to form a homogeneous polymer solution. The finely divided core
material is dispersed in the solution with stirring. Allowing the
mixture to cool with continued stirring, and microencapsulation of
the core material occurs.2. INCOMPATIBLE POLYMER ADDITION:The
polymer which is chemically not compatible will be added to the
coating solutionThe polymer which is to be added should have More
affinity towards solvents No interaction with the core
material.E.g: Addition of liq. Polybutadiene(Incompatible polymer)
to the EC solution in toluene (Coating sol.). Core material:
Methylene blue HCl.Dissolves EC in toluene disperse methylene blue
with stirring slowly add liqpolybutadiene solidification by
addition of hexane filtration and drying of microcapsules.3. SALT
ADDITION: Soluble inorganic salts can be added to aqueous solutions
of certain polymers Should be soluble in water Should precipitate
the polymer from the solution.Eg: Addition of 20% Sod. Sulfate to
the gelatin solution.Core Mat.: Oil soluble vitamin in corn oil.4.
NON-SOLVENT ADDITIONPhase separation can be induced by addition of
non-solvent for given polymer.Have more affinity towards solvent
which is usedPrecipitate the coating polymer Eg: Addition of
Isopropyl ether to Cellulose acetate butyrate (CAB) dissolved in
Methyl ethyl ketone. Core Mat: Methyl Scopolamine HBrsolution of
CAB in MEK Add micronized methylscopolamine with stirring heat 55 C
slowly add isopropyl ether slowly cool to room tempertaure5.
POLYMER- POLYMER INTERACTION (COMPLEX COACERVATION): Core material
Eg: gelatin below its isoelectric pH possess + ve charge, acacia is
vely charged. Core mat: Methyl Salicylate.Both polymers show
attraction due to opposite charge and form coacervate, which is the
deposited around the core due by stirring.Coacervation types on
polymer solution:1) Aqueous phase separation:Core material
hydrophobicCote material hydrophilic
Simple coacervation Water-immiscible liquidaqueous coating
solutionOR (gelatin in water) Water-insoluble solids
O/W emulsion (or)aqueous suspension of solid particleThen add
slowly 20% sod.sulphate solution with continuous stirring
Gel the colloid by pouring coacervate mixture in to 7% w/w
sod.sulphate solution
Filter and wash coacervate with cold water and remove salt
Treat filtered material with formaldehyde to harden the
coacervate
Filter and wash Particles with cold water to remove hardening
agent
Dry to remove remaining solventa) Complex
coacervation:Water-immiscible liquidaqueous coating solutionOR
(acacia in water) Water-insoluble solids
O/W emulsion (or)Aqueous suspension of solid particles
Add gelatin solution with stirring
Add warm water until coacervate is produced
Add coacervate mixture in cold water
Treat filtered material with formaldehyde to harden the
coacervate
Filter and wash Particles with cold water to remove hardening
agent.
Dry to remove remaining solvent
2) Organic phase separation:This method is opposite to aqueous
phase separation.Core material hydrophilicCote material
hydrophobic
Water-miscible liquidpolymer in organic solvent ORWater-soluble
solids
W/O emulsion (or)Suspension of solid particles (in organic
solvent)
Addition of non-solvent for polymer (mineral oil)
Phase separation (microcapsules are produced)
Cooling of microcapsules to solidify coating
Filter wash and dry5. POLYMER ENCAPSULATION BY RAPID EXPANSION
OF SUPERCRITICAL FLUIDSSupercritical fluids are highly compressed
gasses. Properties Possess properties of both liquids and gases
Miscible with common gases such as hydrogen (H2) and
nitrogenCommonly Used Agents Supercritical CO2 Alkanes (C2 to C4)
Nitrous oxide (N2O) Supercritical CO2 is widely used for its
following properties: -Properties Nontoxic Nonflammable Readily
available Highly pure Cost-effectiveApplications It has found
applications in encapsulating active ingredients by polymers.Core
Materials Different core materials such as pesticides,
pharmaceutical ingredients, vitamins, and dyes are encapsulated
using this method.Shell Materials A wide variety of shell materials
that either dissolve (acrylates, polyethylene glycol) or do not
dissolve (proteins, polysaccharides) in supercritical CO2 are used
for encapsulating core substances.MethodsThe most widely used
methods are as follows: Rapid expansion of supercritical solution
(RESS) Gas anti-solvent (GAS) Particles from gas-saturated solution
(PGSS)I Rapid expansion of supercritical solution (RESS)In this
process, supercritical fluid containing the active ingredient and
the shell material are maintained at high pressure and then
released at atmospheric pressure through a small nozzle. The sudden
drop in pressure causes desolvation of the shell material, which is
then deposited around the active ingredient (core) and forms a
coating layer.Disadvantage The disadvantage of this process is that
both the active ingredient and the shell material must be very
soluble in supercritical fluids. The solubility of polymers can be
enhanced by using co-solvents and non-solvents.Example
Microencapsulation of TiO2 nanoparticles with polymer by RESS using
ethanol as a non-solvent for the polymer shell such as polyethylene
glycol (PEG), and polymethyl methacrylate
A schematic of the microencapsulation process using
supercritical CO2
II GAS ANTI-SOLVENT (GAS) PROCESSThis process is also called
supercritical fluid anti-solvent (SAS). Here, supercritical fluid
is added to a solution of shell material andthe active ingredients
and maintained at high pressure. This leads to a volume expansion
of the solution that causes super saturationsuch that precipitation
of the solute occurs. Thus, the solute must be soluble in the
liquid solvent, but should not dissolve in themixture of solvent
and supercritical fluid. On the other hand, the liquid solvent must
be miscible with the supercritical fluid.Advantage It is
alsopossible to produce submicron particles using this method.
Disadvantage This process is unsuitable for the encapsulation of
water-soluble ingredients as water has low solubility in
supercritical fluids.IIIPARTICLES FROM A GAS-SATURATED SOLUTION
(PGSS)This process is carried out by mixing core and shell
materials in supercritical fluid at high pressure. During this
process supercritical fluid penetrates the shell material, causing
swelling. When the mixture is heated above the glass transition
temperature the polymer liquefies. Upon releasing the pressure, the
shell material is allowed to deposit onto the active ingredient. In
this process, the core and shell materials may not be soluble in
the supercritical fluid.
MECHANISMS AND KINETICS OF DRUG RELEASE
Major mechanisms of drug release from microcapsules include
diffusion, dissolution, osmosis and erosion.Diffusion: Diffusion is
the most commonly involved mechanism wherein the dissolution fluid
penetrates the shell, dissolves the core and leak out through the
interstitial channels or pores. Thus, the overall release depends
on, (a) the rate at which dissolution fluid penetrates the wall of
microcapsules, (b) the rate at which drug dissolves in the
dissolution fluid, and (c) the rate at which the dissolved drug
leak out and disperse from the surface. The kinetics of such drug
release obeys Higuchis equation as below: Q
=[D/J(2A-CS)CSt]1/2Where, Q is the amount of drug released per unit
area of exposed surface in time t; D is the diffusion coefficient
of the solute in the solution; A is the total amount of drug per
unit volume; CS is the solubility of drug in permeating dissolution
fluid; is the porosity of the wall of microcapsule; J is the
tortuosity of the capillary system in the wall. The above equation
can be simplified to Q = vt where, v is the apparent release
rate.Dissolution: Dissolution rate of polymer coat determines the
release rate of drug from the microcapsule when the coat is soluble
in the dissolution fluid. Thickness of coat and its solubility in
the dissolution fluid influence the release rate.Osmosis:The
polymer coat of microcapsule acts as semi permeable membrane and
allows the creation of an osmotic pressure difference between the
inside and the outside of the microcapsule and drives drug solution
out of the microcapsule through small pores in the coat.Erosion:
Erosion of coat due to pH and/or enzymatic hydrolysis causes drug
release with certain coat materials like glycerylmonostearate, bees
wax and stearyl alcohol.11Attempts to model drug release from
microcapsules have become complicated due to great diversity in
physical forms of microcapsules with regard to size, shape and
arrangement of the core and coat materials. The physiochemical
properties of core materials such as solubility, diffusibility and
partition coefficient, and of coating materials such as variable
thickness, porosity, and inertness also makes modeling of drug
release difficult.
Loading Of Drug In Microsphere:Mechanisms For Loading Drug:Drug
can be loaded by a. physical entrapment b. chemical linkagec.
surface adsorption The active components are loaded over the
microsphere principally at two points a. During the preparation of
microsphere b. After the formation of microsphere by incubating
them with the drug or protein. MAXIMUM LOADING can be achieved by
incorporating drug during the time of preperation.Loading during
preparation is avoided because during prep loading is effected by
1) Method of preparation.2) Presence of additives e.g. crosslinking
agent, surfactant stabilizer.3) Heat of polymerization.4) Agitation
intensity.KINETICS OF DRUG RELEASE:
In some cases, the release rateis zero-order, i.e. the release
rate is constant. In this case, the microcapsules deliver a fixed
amount of drug per minute or hour during the period of their
effectiveness. This can occur as long as a solid reservoir or
dissolving drug is maintained in the microcapsule.A more typical
release pattern is first-order in which the rate decreases
exponentially with time until the drug source is exhausted. In this
situation, a fixed amount of drug is in solution inside the
microcapsule. The concentration difference between the inside and
the outside of the capsule decreases continually as the drug
diffuses.
APPLICATIONS OF MICROENCAPSULATION(A) PHARMACEUTICAL
APPLICATIONS:(1) CONTROLLED DRUG RELEASE:Many varieties of both
oral and injectable pharmaceutical formulations are
microencapsulated to release the drug over longer period of time.
Aspirin controlled release version Zorprin CR tablet that is used
for arthritis. Niaspan CR tablets that is used for lowering
cholesterol levels and it reduces the risk of heart attack.
(2) TARGETTED DRUG RELEASE:Certain anti-tumor drugs are
microencapsulated for targeted drug
delivery.Alginate-Poly-L-Lysine-Alginate microcapsules of
anti-tumor drugs are mostly used and they bind to tumor antigen
TAG72.
(3) RECOMBINANT GENE THERAPY:Corrective gene sequence in the
form of plasmids are microencapsulated to be incorporated in the
body for the treatment of genetic disorders.
(4) ENZYME AND MICROBES IMMOBILIZATION:Enzymes have been
encapsulated in cheese to accelerate ripening and flavor
development. The encapsulated enzymes are protected from low pH and
high ionic strength in cheese.Encapsulation of microbes has been
used to improve stability of starter culture.
(5) IMPROVED SHELF LIFE:Microencapsulation of drugs enhances
their shelf life by preventing degradative reactions (dehydration
and oxidation).
(6) PROTECTION AGAINST ENVIRONMENTAL EFFECTS:Microencapsulation
protects the drugs against environmental effects of UV rays, heat,
oxidation, acids and bases. E.g: microencapsulation of vitamin A
palmitate and vitamin K.
(7) MASKING OF BITTER TASTE AND ODOUR:Microencapsulation masks
the bitter taste of drugs like paracetamol and nitrofurantoin
etc.It also decreases the odour and volatility of certain compounds
like carbon tetrachloride (CTC).
(8) IMPROVED PROCESSING, TEXTURE AND LESS WASTAGE OF
INGREDIENTS: Control of hygroscopy (NaCl) Enhanced flowability and
dispersibilityMicroencapsulation of non-flowing multicomponent
solid mixture of thiamine, riboflavin, niacin and iron phosphate
for easy tableting. Enhanced solubility
(9) MIXING OF INCOMPATIBLE COMPOUNDS:Microencapsulation allows
mixing of incompatible compounds like for easy addition of oily
ingredients in formulations.
(10) MICROENCAPSULATION OF INSULINE AND PANCREATIC ISLETS: For
better and prolonged therapeutic effects of insulin. For the
improvement of compromised pancreatic function.