Caleva Process Solutions
http://www.caleva.com
Another resourceful Powerpoint Presentation from Caleva Process Solutions. These selection of slides will provide you with some very useful information on Extrusion Spheronization. This includes general information, the process of Extrusion Spheronization, Wet Massing and Pelletization!
For more information on Extrusion Spheronization, visit:
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Targeted Drug Delivery System achieves maximum bioavailability thus proving to be therapeutically efficacious & with minimal side effects. This presentation won the First Prize at MSBTE sponsored State Level Technical Paper
Presentation Competition, 2017.
Caleva Process Solutions
http://www.caleva.com
Another resourceful Powerpoint Presentation from Caleva Process Solutions. These selection of slides will provide you with some very useful information on Extrusion Spheronization. This includes general information, the process of Extrusion Spheronization, Wet Massing and Pelletization!
For more information on Extrusion Spheronization, visit:
http://caleva.com/
Targeted Drug Delivery System achieves maximum bioavailability thus proving to be therapeutically efficacious & with minimal side effects. This presentation won the First Prize at MSBTE sponsored State Level Technical Paper
Presentation Competition, 2017.
Easy & to the point Topics are clearly given in this presentation..
Thanks & Best Regard
(Anurag Pandey) B.Pharm
Contact :- anurag.dmk05@gmail.com (Facebook & Gmail both)
It includes Introductory part about what is Dissolution...then Mechanism of Dissolution is elaborated...Theories of Dissolution also given..It also includes Factors affecting Dissolution profile..Along with References given below for easily searching..
Easy & to the point Topics are clearly given in this presentation..
Thanks & Best Regard
(Anurag Pandey) B.Pharm
Contact :- anurag.dmk05@gmail.com (Facebook & Gmail both)
It includes Introductory part about what is Dissolution...then Mechanism of Dissolution is elaborated...Theories of Dissolution also given..It also includes Factors affecting Dissolution profile..Along with References given below for easily searching..
unit 2. various approaches on Microencapsulation.pdfAkankshaPatel55
Microencapsulation is a process of coating tiny particles or droplets with a thin layer of material to create small capsules. These capsules, called microcapsules, can range in size from a few nanometers to a few millimeters and can be made from a variety of materials, such as polymers, lipids, and carbohydrates.
The core material of a microcapsule can be a solid, liquid, or gas. Some common core materials include:
Food ingredients: Vitamins, flavors, colors, antioxidants
Pharmaceuticals: Drugs, diagnostic agents
Agrochemicals: Pesticides, fertilizers, herbicides
Cosmetics: Fragrances, sunscreens, moisturizers
Electronics: Conductive materials, lubricants
The shell of a microcapsule is designed to protect the core material from the environment and to control its release. The release of the core material can be triggered by a variety of factors, such as:
Temperature
pH
Enzymes
Ultrasound
Applications in various industries, including:
Food industry: it is used to protect food ingredients from degradation, such as vitamins and flavors. It can also be used to control the release of flavors and colors, creating novel food experiences.
Pharmaceutical industry: used to improve the delivery of drugs by protecting them from the stomach environment and targeting them to specific sites in the body.
Agrochemical industry: used to protect agrochemicals from degradation and to control their release, reducing the amount of chemicals needed and minimizing environmental impact.
Cosmetic industry: used to protect cosmetic ingredients from degradation and to control their release, creating long-lasting products.
Electronics industry: used to protect electronic components from corrosion and to control the release of lubricants.
TECHNIQUES
Physicochemical techniques:
Coacervation: Involves layering oppositely charged polymers around the core material, forming a shell through electrostatic interaction.
Interfacial polymerization Utilizes monomers that react at the interface between the core and an immiscible phase, generating a polymer shell.
In situ polymerization: Monomers are directly polymerized around the core material within a continuous phase, creating the shell.
Spray drying: Emulsified or suspended core material is atomized and dried in a hot air stream, forming microcapsules as the solvent evaporates.
Fluidized bed coating: Core material is fluidized in a heated chamber while coating solution is sprayed, forming a layer-by-layer shell.
Physico-mechanical techniques:
Pan coating: Similar to sugar-coating, core material is layered with coating material in a rotating pan, building the shell gradually.
Extrusion: Molten core and coating materials are co-extruded to form capsules with con concentric layers.
Encapsulation by solvent evaporation: Core material is dissolved in a solvent, then dispersed in a non-solvent, causing precipitation and shell formation.
Other techniques:
Electrostatic encapsulation,
Microfluidic encapsulation.
Novel Herbal Drug Microsphere Types of Preparation Characterization and Appli...ijtsrd
Microparticals are also known as microspheres. The free flowing protein based powder that makes up microspheres typically has a particle size range of 1 1000um. The microsphere are a cutting edge alternative to conventional or immediate release single unit dosage forms for effective therapeutic drug delivery. The efficiency of the microsphere that are created using various methods that are modified, as well as the administration of the dosage form, are compared to traditional Form. The dose of the microsphere will be assessed using two separate techniques waxe containing, and hot melt. Techniques for spray drying, solvent evaporation, and pre petition. Freeze Drying, lonic gelain method. The microsphere will get central place in novel novel drug delivery manufacture. 1 Nilesh Gavali | Radhika Kotme "Novel Herbal Drug Microsphere Types of Preparation Characterization and Application: A Review" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-7 , December 2022, URL: https://www.ijtsrd.com/papers/ijtsrd52410.pdf Paper URL: https://www.ijtsrd.com/pharmacy/novel-drug-delivery-sys/52410/novel-herbal-drug-microsphere-types-of-preparation-characterization-and-application-a-review/nilesh-gavali
microencapsulation is the part of an pharmaceutics, in that the method of preperation is giving. and all related thing about microencapsulation is given.
thanks you.
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2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
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Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
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The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
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In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
2. Definition of Micro encapsulation
Reasons for Micro encapsulation
Core and Coating Materials
Mechanism of Drug Release
Disadvantage
Microcapsule
Definition
Classification
Core and Coating Materials
Manufacturing technique
Marketed formulations
2
3. Microencapsulation 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.
Or
Microencapsulation is the process by which tiny solid particles or
droplets of liquid are surrounded or coated with a continuous film
of polymeric material to produce capsules in the micrometer to
millimetre range. The product obtained by this process is called as
microcapsules. 3
5. It is mean of applying thin coating to small particle of solid or
droplet of liquid & dispersion.
Particle size: 50-5000 micron.
It has 2 main phases: a) Core material b) Coating material
Also known as microcapsule, microsphere, coated granules,
pellets.
5
6. For sustained or prolonged drug release.
For masking taste and odour of many drugs to improve patient
compliance.
For converting liquid drugs in a free flowing powder.
To reduce toxicity and GI irritation
Incompatibility among the drugs can be prevented by
microencapsulation.
The drugs, which are sensitive to oxygen, moisture or light, can
be stabilized by microencapsulation
6
7. The material to be coated :-
It may be liquid or solid
Liquid core may be dissolved or dispersed material
Composition of coating material:
Drug or active constituent
Additive like diluents
Stabilizers
Release rate enhancers
7
8. Inert substance which coats on core with desired thickness
Compatible with the core material
Stabilization of core material.
Inert toward active ingredients.
Controlled release under specific conditions.
The coating can be flexible, brittle, hard, thin etc.
Abundantly and cheaply available
Composition of coating :-
Inert polymer
Plasticizer
Colouring agent 8
9. Example of Coating materials:
Gums:- Gum arabic, sodium alginate, carragenan
Carbohydrates:- Starch, dextran, sucrose
Celluloses:- Carboxymethylcellulose, methycellulose.
Lipids:- Bees wax, stearic acid, phospholipids.
Proteins:- Gelatin, albumin
9
11. Mechanism of Drug Release
Degradation
Controlled
monolith
System
Diffusion
Controlled
Monolith
System
Diffusion
Controlled
Reservoir
System
Erosion
11
12. 1)Degradation controlled monolithic system- Drug releases on
degradation of matrix.
2)Diffusion controlled monolithic system- Drug released by
diffusion then degradation of matrix occurs.
3)Diffusion controlled reservoir system- Drug from capsule
diffuses then rate controlling membrane erodes.
4)Erosion-Due to pH and enzymatic hydrolysis.
12
13. To improve the flow properties. e.g. Thiamine, Riboflavine
To enhance the stability. e.g. Vitamins
To reduce the volatility of materials. e.g. Peppermint oil,
Methyl salicylate
To avoid incompatibilities. e.g. Aspirin and Chloramphenicol
To mask the unpleasant taste and odour. e.g. Aminophylline,
castor oil
To convert liquids into solids. e.g. Castor oil, Eprazinone,
To reduce gastric irritation. e.g. Nitrofurantoin, Indomethacin
13
14. Possible cross reaction between core and shell material.
Difficult to achieve continuous and uniform film.
Shelf life of hygroscopic drugs is reduced.
More production costs.
More skill and knowledge is required
14
16. Applications of Microcapsules and Microspheres
36
1. AgriculturalApplications
Reduce insect populations by disrupting their mating process.
Protects the pheromone from oxidation and light during storage
and release.
17. 37
2. Catalysis
Safe handling, easy recovery, reuse and disposal at an acceptable
economic cost.
Metal species such as palladium (II) acetate and osmium tetroxide
have been encapsulated in polyurea microcapsules and used
successfully as recoverable and reusable catalysts without
significant leaching and loss of activity.
18. 38
3. Food Industry
Adding ingredients to food products to improve nutritional value
can compromise their taste, colour, texture and aroma.
Sometimes they slowly degrade and lose their activity, or
become hazardous by oxidation reactions.
Ingredients can also react with components present in the food
system, which may limit bioavailability.
19. 39
4. Pharmaceutical Applications
Potential applications of this drug delivery system are
replacement of therapeutic agents (not taken orally today like
insulin), gene therapy and in use of vaccines for treating AIDS,
tumors, cancer and diabetes.
The delivery of corrective gene sequences in the form of plasmid
DNA could provide convenient therapy for a number of genetic
diseases such as cystic fibrosis and hemophilia.
20. 40
Lupin has already launched in the market worlds first
Cephalexin (Ceff-ER) and Cefadroxil (Odoxil OD) antibiotic
tablets for treatment of bacterial infections.
Aspirin controlled release version ZORprin CR tablets are used
for relieving arthritis symptoms.
Quinidine gluconate CR tablets are used for treating and
preventing abnormal heart rhythms.
Niaspan CR tablet is used for improving cholesterol levels and
thus reducing the risk for a heart attack.
21. 41
Glucotrol (Glipizide SR) is an anti diabetic medicine used to
control high blood pressure.
Some of the applications of microencapsulation can be
described in detail as given below:
1. Prolonged release dosage forms.
2. Prepare enteric-coated dosage forms selectively absorbed in the
intestine rather than the stomach.
3. It can be used to mask the taste of bitter drugs.
4. To reduce gastric irritation.
22. 42 5. Used to aid in the addition of oily medicines to tablet dosage
forms.
To overcome problems inherent in producing tablets from
otherwise tacky granulations.
This was accomplished through improved flow properties.
eg. The non-flowable multicomponent solid mixture of niacin,
riboflavin, and thiamine hydrochloride and iron phosphate may be
encapsulated and made directly into tablets.
23. 43 6. To protect drugs from environmental hazards such as
humidity, light, oxygen or heat. eg. vitamin A and K have been
shown to be protected from moisture and oxygen through
microencapsulation.
7. The separations of incompatible substances, eg. pharmaceutical
eutectics.
The stability enhancement of incompatible aspirin-
chlorpheniramine maleate mixture was accomplished by
microencapsulating both of them before mixing.
24. 44
8. Microencapsulation can be used to decrease the volatility.
9. The hygroscopic properties of many core materials may be
reduced by microencapsulation.
10.In the fabrication of multilayered tablet formulations for
controlled release of medicament contained in medial layers of
tableted particles.
11.Microencapsulation has also been used to decrease potential
danger of handling of toxic or noxious substances. Such as
fumigants, herbicides, insecticides and pesticides
27. Microcapsule is a tiny capsule , containing material such as
medicine, that is released when the capsule is broken , melted
or dissolved.
Microcapsules contain an active agent and surrounded
polymeric shell or dispersed in polymeric matrix.
Microcapsule size : 1 to 1000 micron
Microcapsules can be of different structures
27
30. Category of Coating
Material
Examples
Water soluble resins Gelatin,
Polyvinylpyrrolidone (PVP).
Water insoluble resins Ethyl cellulose, Polyethylene
Waxes and lipids Paraffin, Carnauba, Beeswax
Enteric resins Shellac, Zein
30
31. SL
No.
Physical Methods Chemical
Methods
A) Air Suspension Solvent Evaporation
B) Pan Coating Polymerization
C) Coarcervation Phase Separation
D) Multi-orifice Centrifugal Process
E) Spray Drying & Spray Congealing
F) Fluidized Bed Technology
23
33. Sl
No
.
Method Applicable
materials
Particle
Size
Productio
n scale
Time
Required
Cost
1 Air Suspension Solid 35-5000 Pilot Scale High High
2 Pan Coating Solid 600-
5000
Pilot Scale High High
3 Coacervation
and Phase
Separation
Solid and
liquid
2-5000 Lab Scale Less Less
4 Multi-orifice
centrifugal
Solid and
liquid
1-5000 Pilot Scale High High
5 Solvent
Evaporation
Solid and
liquid
5-5000 Lab Scale Less Less
6 Spray Drying
and Spray
Congealing
liquid 600 Pilot Scale High High
25
34. Within the coating chamber, particles are suspended on an upward
moving air stream.
Spraying of coating material on the air suspended particles.
The cyclic process is repeated depending upon purpose of
microencapsulation.
Air stream serves to dry the product.
34
35. 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
air stream.
35
36. The design of the chamber and its operating parameters effect a
recalculating flow of the particles through the coating zone
portion of the chamber, where a coating material, usually a
polymer solution, is spray applied to the moving particles.
36
37. D
u
r
i
n
g e
ach 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.
The supporting air stream also serves to dry the product while it is
being encapsulated. Drying rates are directly related to the volume
temperature of the supporting air stream. 29
39. Concentration of Coating materials
Solubility , Surface area, density, melting point and Volatility.
Application rate of coating materials
Temperature of air stream.
The amount of required to fluidized the core materials.
39
40. The particles are tumbled in a pan while the coating
material is applied slowly as solution or atomized spray to
the core.
To remove the coating solvent, warm air is passed over the
coated materials.
Medicaments are usually coated onto nonpareil sugar
seeds and then coated with polymers
40
42. Solid particles are mixed with a dry coating material.
The temperature is raised so that the coating material melts and
encloses the core particles, and then is solidified by cooling.
Or, the coating material can be gradually applied to core
particles tumbling in a vessel rather than being wholly mixed
with the core particles from the start of encapsulation.
42
45. Simple coacervation Complex coacervation
A desolvation agent is addedfor
phase separation
It involves complexation
between two oppositely
charged polymers.
Steps involved in this process are:-
1)Formation of three immiscible phases.
2)Deposition of liquid coating material upon the core material.
3) Rigidization of coating.
45
46. Formation of three immiscible phases; a liquid manufacturing
phase, a core material phase and a coating material phase.
Deposition of the liquid polymer coating on the core material.
Rigidizing the coating usually by thermal, cross linking or
desolvation techniques to form a microcapsule.
In step 2, the deposition of the liquid polymer around the interface
formed between the core material and the liquid vehicle phase. In
many cases physical or chemical changes in the coating polymer
solution can be induced so that phase separation of the polymer
will occur.
46
47. Droplets of concentrated polymer solution will form and
coalesce to yield a two phase liquid-liquid system. In cases in
which the coating material is an immiscible polymer of insoluble
liquid polymer it may be added directly. Also monomers can be
dissolved in the liquid vehicle phase and subsequently
polymerized at interface.
Equipment required for microencapsulation this method is
relatively simple; it consists mainly of jacketed tank with
variable speed agitator.
47
50. Various methods to obtain three immiscible phases
50
1) Temperature change
2) Incompatible PolymerAddition
3) Non-SolventAddition
4) SaltAddition
5) Polymer-Polymer Interaction(Complex Coacervation)
51. Temperature Change:- Changing temperature of polymer
solution, Example:- Ethyl cellulose in cyclohexane.
Incompatible polymer addition :- Addition of incompatible
polymer to the polymer solution , e.g. Addition of
polybutadiene to the solution of ethyl cellulose in toluene.
Non Solvent Addition:- e.g. Addition of isopropyl ether to
methyl ethyl ketone solution of cellulose acetate butyrate.
Addition of Salt :- e.g. Addition of Sodium sulphate solution
to gelatin solution in vitamin encapsulation
Polymer-polymer interaction:- e.g. Interaction of gum arabic
and gelatin at their isoelectric point
51
52. The Southwest Research Institute (SWRI) has developed a
mechanical process for producing microcapsules that utilizes
centrifugal forces to hurl a core material particle trough an
enveloping microencapsulation membrane thereby effecting
mechanical microencapsulation. Processing variables include the
rotational speed of the cylinder, the flow rate of the core and
coating materials, the concentration and viscosity and surface
tension of the core material.
52
53. The multiorifice-centrifugal process is capable for
microencapsulating liquids and solids of varied size ranges, with
diverse coating materials. The encapsulated product can be
supplied as slurry in the hardening media or as a dry powder.
Production rates of 50 to 75 pounds per our have been achieved
with the process.
53
54. Cylinder Rotating Speed
Core and Coating materials Flow Rate
Viscosity
Surface tension
Concentration ofCore material
54
57. Spray Drying : Microencapsulation by spray-drying is a low-
cost commercial process which is mostly used for the
encapsulation of fragrances, oils and flavours.
Steps:
1- Core particles are dispersed in a polymer solution and
sprayed into a hot chamber.
57
58. 2- The shell material solidifies onto the core particles as the
solvent evaporates. The microcapsules obtained are of
Polynuclear or matrix type.
The coating solidification effected by rapid evaporating of
solvent in which coating material is dissolved.
58
59. 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.
59
60. 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.
The coating solidification is effected by thermally congealing a
molten coating material. The removal of solvent is done by
sorption, extraction or evaporation technique
60
64. The liquid coating is sprayed onto the particles and the rapid
evaporation helps in the formation of an outer layer on the
particles.
The thickness and formulations of the coating can be obtained as
desired. Different types of fluid-bed coaters include top spray
,bottom spray, and tangential spray
64
65. In the top spray system the coating materials is sprayed
downwards onto the fluid bed such that as the solid or porous
particle move to coating region they become encapsulated.
The bottom spray is also known as “Wurster`s Coater” in
reorganization of its development by Prof. D.E. Wurster.
65
66. 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 edge of the chamber and the disc. The tangential
nozzle is placed above the rotating disc through which coating
material is released . The particle move through the gap into the
spraying zone and are encapsulated. As they travel a minimum
distance there is higher yield of encapsulated particles.
66
68. Core material
Dissolved Or Dispersed
Coating polymer solution
WithAgitation
Liquid Manufacturing Vehicle Phase
Heating (If necessary)
Evaporation of Polymer solvent
Microencapsulation 60
69. This technique has been used by companies including the NCR
Company, Gavert Photo production NV, and Fuji Photo Film Co.
Ltd. To produce microcapsule.
In this, Volatile Solvent is Dissolved in microcapsule coating
material, which is immiscible with the liquid manufacturing
vehicle phase.
69
70. The core material to be encapsulated is dispersed in the solution of
coating polymer .Continuous agitation is carried out, and then
core coating material mixture is dispersed in the liquid
manufacturing vehicle phase to give specific size of microcapsule.
Then the solvent evaporate from the polymer solution after
heating the mixture.
The solvent evaporation technique is used to formulate various
types of microcapsule, for example, evolution of sucrose esters as
an alternative surfactants in microencapsulation of proteins by the
solvent evaporation method.
70
72. The method involve the reaction of monomeric unit located at
the interface existing between a core material substance and
continuous phase in which the core material is disperse.
The core material supporting phase is usually a liquid or gas,
and therefore polymerization reaction occur at liquid-liquid,
liquid-gas, solid-liquid, or solid-gas interface.
E.g. In the formation of polyamide (Nylon) polymeric reaction
occurring at liquid-liquid interface existing between aliphatic
diamine & dicarboxylic acid halide.
72
73. Preparation of the polymerization
mixture
Drug Monomer(s) (e.g. acrylamide)
Cross-linker
(e.g.Methylenebisacrylamide)
+ +
Initiation of Polymerization
Monodisoerse Latex Formation by
Polymer Precipitation
Recovery of Polymeric
Microparticles
Alcohol
Addition of the alcoholic
solution of the initiator
8hrs reaction
time
73
84. 1)Percentage Yield :- The total amount of microcapsules obtained
was weighed and the percentage yield calculated taking into
consideration the weight of the drug and polymer.
Percentage yield = Amount of microcapsule obtained / Theoretical
Amount×100
2)Scanning electron microscopy :- Scanning electron
photomicrographs of drug loaded ethyl cellulose microcapsules
were taken. A small amount of microcapsules was spread on gold
stub and was placed in the scanning electron microscopy (SEM)
chamber. The SEM photomicrographs was taken at the
acceleration voltage of 20 KV.
84
85. 3)Particle size analysis :- For size distribution analysis, different
sizes in a batch were separated by sieving by using a set of
standard sieves. The amounts retained on different sieves were
Encapsulation efficiency was
85
weighed .
4)Encapsulation efficiency:-
calculated using the formula.
Encapsulation efficiency = Actual Drug Content /
Theoretical Drug Content ×100
86. 5) Estimation of Drug Content:- Drug content in the microcapsules
was calculated by UV spectrophotometric method. The method
was validated for linearity, accuracy and precision. A sample of
microcapsules equivalent to 100 mg was dissolved in 25 ml
ethanol and the volume was adjusted up to 100 ml using phosphate
buffer of pH 7.4. The solution was filtered through Whatman filter
paper. Then the filtrate was assayed for drug content by measuring
the absorbance at specific wavelength after suitable dilution.
86
87. 6) Invitro Drug release Studies
87
Drug release was studied by using USP type II dissolution test
apparatus in Phosphate buffer of pH 7.4 (900 ml). The paddle
speed at 100 rpm and bath temperature at 37 ± 0.5°c were
maintained through out the experiment.
A sample of microcapsules equivalent to 100 mg of drug was used
in each test. Aliquot equal to 5ml of dissolution medium was
withdrawn at specific time interval and replaced with fresh
medium to maintain sink condition. Sample was filtered through
Whatman No. 1 filter paper and after suitable dilution with
medium; the absorbance was determined by UV
spectrophotometer at specific wavelength.
All studies were conducted in triplicate (n=3). The release of drug
from marketed sustained release preparation was also studied to
compare with release from microcapsules.
88. 7) Diffusion:- Diffusion is a common mechanism of drug release
in which dissolution fluid penetrates the shell and then core
material comes in contact with the fluid and leak out through the
interstitial channels or pores.
88
89. 8) Thermal Analysis:- It is use for determination of drug
performance after encapsulation in terms of change of drug
behaviour and studied by DSC.
9)Molecular Weight:- Molecular Weight of the microcapsule is
done by Gel Permeation Chromatography.
89
90. SL No. Brand Name Generic Name Category of
Drug
1 Lupin Cafedroxil Antibiotic
2 Zorprine CR Aspirin Anti - arthritic
3 Glipizide SR Glucotrol Anti diabetic
85
91. Micro encapsulation ppt by – SANATABASSUM
A Review on Microcapsules :- Azagheswari, BinilKuriokase,
Sathireddy Padma and S. Padma Priya
Micro-encapsulation : at Crossroads of Art, Science and
Technology
MICROENCAPSULATION: A REVIEW JYOTHI SRI.S* ,
A.SEETHADEVI , K.SURIA PRABHA ,
P.MUTHUPRASANNAAND ,P.PAVITRA
91