Microspheres are solid spherical particles made of polymers that can encapsulate drugs. They range in size from 1-1000μm. There are various methods for producing microspheres, including single and double emulsion techniques, polymerization methods, coacervation, spray drying, and solvent extraction. Microspheres offer advantages like controlled drug release, protection of unstable drugs, and targeting of specific tissues. They have various pharmaceutical applications including vaccine and drug delivery, with the ability to control release kinetics and target specific sites.
Application Of Polymer In Controlled Release FormulationAnindya Jana
Polymers are becoming increasingly important in the field of drug delivery. The pharmaceutical applications of polymers range from their use as binders in tablets to viscosity and flow controlling agents in liquids, suspensions and emulsions. Polymers can be used as film coatings to disguise the unpleasant taste of a drug, to enhance drug stability and to modify drug release characteristics.
As a consequence, increasing attention has been focused on methods of giving drugs continually for a prolonged time periods and in a controlled fashion.
This technology now spans many fields and includes pharmaceutical, food and agricultural applications, pesticides, cosmetics, and household products.
Application Of Polymer In Controlled Release FormulationAnindya Jana
Polymers are becoming increasingly important in the field of drug delivery. The pharmaceutical applications of polymers range from their use as binders in tablets to viscosity and flow controlling agents in liquids, suspensions and emulsions. Polymers can be used as film coatings to disguise the unpleasant taste of a drug, to enhance drug stability and to modify drug release characteristics.
As a consequence, increasing attention has been focused on methods of giving drugs continually for a prolonged time periods and in a controlled fashion.
This technology now spans many fields and includes pharmaceutical, food and agricultural applications, pesticides, cosmetics, and household products.
Introduction
Structure
Niosomes Vs. Liposome
Advantages & Disadvantages
Properties of Niosomes
Method of Manufacturing
Evaluation of Niosomes
Applications
Marketed products
Liposomes-Classification, methods of preparation and application Vijay Hemmadi
liposome preparation and application
A liposome is a tiny bubble (vesicle), made out of the same material as a cell membrane. Liposomes can be filled with drugs, and used to deliver drugs for cancer and other diseases. Membranes are usually made of phospholipids, which are molecules that have a head group and a tail group
‘Targeted drug delivery system is a special form of drug delivery system where the medicament is selectively targeted or delivered only to its site of action or absorption and not to the non-target organs or tissues or cells.’
NIOSOMES , GENERAL CHARACTERISTICS OF NIOSOME , TYPES OF NIOSOMES , OTHERS TYPES OF NIOSOMES , NIOSOMES VS LIPOSOMES , COMPONENTS OF NIOSOMES , Non-ionic surfactant , Cholesterol , Charge inducing molecule , METHOD OF PREPARATION , preparation of small unilamellar vesicles , Sonication , Micro fluidization , preparation of large unilamellar vesicles , Reverse Phase Evaporation , Ether Injection , preparation of Multilamellar vesicles , Hand shaking method , Trans membrane pH gradient drug uptake process (remote loading) , Miscellaneous method :Multiple membrane extrusion method , The “Bubble” Method , Formation of Niosomes From Proniosomes , SEPARATION OF UNENTRAPPED DRUGS , Gel Filtration , Dialysis , Centrifugation , FACTORS AFFECTING THE PHYSICOCHEMICAL PROPERTIES OF NIOSOMES , Membrane Additives , Temperature of Hydration , PROPERTIES OF DRUGS , AMOUNT AND TYPE OF SURFACTANT
Structure of Surfactants , Resistance to Osmotic Stress , Characterization of niosomes ,Therapeutic applications of Niosomes , For Controlled Release of Drugs , To Improve the Stability and Physical Properties of the Drugs , For Targeting and Retention of Drug in Blood Circulation , Proniosomes , Aspasomes , Vesicles in Water and Oil System (v/w/o) ,Bola - niosomes , Discomes , Deformable niosomes or elastic niosomes , According to the nature of lamellarity ,Small Unilamellar vesicles (SUV) 25 – 500 nm in size.,Large Unilamellar vesicles (LUV) 0.1 – 1μm in size , Multilamellar vesicles (MLV) 1-5 μm in size , According to the size:Small Niosomes (100 nm – 200 nm) , Large Niosomes (800 nm – 900 nm),Big Niosomes (2 μm – 4 μm)
Mucoadhesive drug delivery system interact with the mucus layer covering the mucosal epithelial surface, & mucin molecules & increase the residence time of the dosage form at the site of the absorption.
Mucoadhesive drug delivery system is a part of controlled delivery system.
Since the early 1980,the concept of Mucoadhesion has gained considerable interest in pharmaceutical technology.
combine mucoadhesive with enzyme inhibitory & penetration enhancer properties & improve the patient complaince.
MDDS have been devloped for buccal ,nasal,rectal &vaginal routes for both systemic & local effects.
Hydrophilic high mol. wt. such as peptides that cannot be administered & poor absorption ,then MDDS is best choice.
Mucoadhesiveinner layers called mucosa inner epithelial cell lining is covered with viscoelasticfluid
Composed of water and mucin.
Thickness varies from 40 μm to 300 μm
General composition of mucus
Water…………………………………..95%
Glycoproteinsand lipids……………..0.5-5%
Mineral salts……………………………1%
Free proteins…………………………..0.5-1%
The mechanism responsible in the formation of mucoadhesive bond
Step 1 : Wetting and swelling of the polymer(contact stage)
Step 2 : Interpenetration between the polymer chains and the mucosal membrane
Step 3 : Formation of bonds between the entangled chains (both known as consolidation stage)
Electronic theory
Wetting theory
Adsorption theory
Diffusion theory
Fracture theory
Advantages over other controlled oral controlled release systems by virtue of prolongation of residence of drug in GIT.
Targeting & localization of the dosage form at a specific site
-Painless administration.
-Low enzymatic activity & avoid of first pass metabolism
If MDDS are adhere too tightlgy because it is undesirable to exert too much force to remove the formulation after use,otherwise the mucosa could be injured.
-Some patient suffers unpleasent feeling.
-Unfortunately ,the lack of standardized techniques often leads to unclear results.
-costly drug delivery system
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)
Introduction
Structure
Niosomes Vs. Liposome
Advantages & Disadvantages
Properties of Niosomes
Method of Manufacturing
Evaluation of Niosomes
Applications
Marketed products
Liposomes-Classification, methods of preparation and application Vijay Hemmadi
liposome preparation and application
A liposome is a tiny bubble (vesicle), made out of the same material as a cell membrane. Liposomes can be filled with drugs, and used to deliver drugs for cancer and other diseases. Membranes are usually made of phospholipids, which are molecules that have a head group and a tail group
‘Targeted drug delivery system is a special form of drug delivery system where the medicament is selectively targeted or delivered only to its site of action or absorption and not to the non-target organs or tissues or cells.’
NIOSOMES , GENERAL CHARACTERISTICS OF NIOSOME , TYPES OF NIOSOMES , OTHERS TYPES OF NIOSOMES , NIOSOMES VS LIPOSOMES , COMPONENTS OF NIOSOMES , Non-ionic surfactant , Cholesterol , Charge inducing molecule , METHOD OF PREPARATION , preparation of small unilamellar vesicles , Sonication , Micro fluidization , preparation of large unilamellar vesicles , Reverse Phase Evaporation , Ether Injection , preparation of Multilamellar vesicles , Hand shaking method , Trans membrane pH gradient drug uptake process (remote loading) , Miscellaneous method :Multiple membrane extrusion method , The “Bubble” Method , Formation of Niosomes From Proniosomes , SEPARATION OF UNENTRAPPED DRUGS , Gel Filtration , Dialysis , Centrifugation , FACTORS AFFECTING THE PHYSICOCHEMICAL PROPERTIES OF NIOSOMES , Membrane Additives , Temperature of Hydration , PROPERTIES OF DRUGS , AMOUNT AND TYPE OF SURFACTANT
Structure of Surfactants , Resistance to Osmotic Stress , Characterization of niosomes ,Therapeutic applications of Niosomes , For Controlled Release of Drugs , To Improve the Stability and Physical Properties of the Drugs , For Targeting and Retention of Drug in Blood Circulation , Proniosomes , Aspasomes , Vesicles in Water and Oil System (v/w/o) ,Bola - niosomes , Discomes , Deformable niosomes or elastic niosomes , According to the nature of lamellarity ,Small Unilamellar vesicles (SUV) 25 – 500 nm in size.,Large Unilamellar vesicles (LUV) 0.1 – 1μm in size , Multilamellar vesicles (MLV) 1-5 μm in size , According to the size:Small Niosomes (100 nm – 200 nm) , Large Niosomes (800 nm – 900 nm),Big Niosomes (2 μm – 4 μm)
Mucoadhesive drug delivery system interact with the mucus layer covering the mucosal epithelial surface, & mucin molecules & increase the residence time of the dosage form at the site of the absorption.
Mucoadhesive drug delivery system is a part of controlled delivery system.
Since the early 1980,the concept of Mucoadhesion has gained considerable interest in pharmaceutical technology.
combine mucoadhesive with enzyme inhibitory & penetration enhancer properties & improve the patient complaince.
MDDS have been devloped for buccal ,nasal,rectal &vaginal routes for both systemic & local effects.
Hydrophilic high mol. wt. such as peptides that cannot be administered & poor absorption ,then MDDS is best choice.
Mucoadhesiveinner layers called mucosa inner epithelial cell lining is covered with viscoelasticfluid
Composed of water and mucin.
Thickness varies from 40 μm to 300 μm
General composition of mucus
Water…………………………………..95%
Glycoproteinsand lipids……………..0.5-5%
Mineral salts……………………………1%
Free proteins…………………………..0.5-1%
The mechanism responsible in the formation of mucoadhesive bond
Step 1 : Wetting and swelling of the polymer(contact stage)
Step 2 : Interpenetration between the polymer chains and the mucosal membrane
Step 3 : Formation of bonds between the entangled chains (both known as consolidation stage)
Electronic theory
Wetting theory
Adsorption theory
Diffusion theory
Fracture theory
Advantages over other controlled oral controlled release systems by virtue of prolongation of residence of drug in GIT.
Targeting & localization of the dosage form at a specific site
-Painless administration.
-Low enzymatic activity & avoid of first pass metabolism
If MDDS are adhere too tightlgy because it is undesirable to exert too much force to remove the formulation after use,otherwise the mucosa could be injured.
-Some patient suffers unpleasent feeling.
-Unfortunately ,the lack of standardized techniques often leads to unclear results.
-costly drug delivery system
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)
magnetic microspheres a noval drug delivery system in this we are learn about microshperes , magnetic microsphere and preparation method of magnetic microsphere.
In this presentation incude method of preparation ,evaluvation of magnetic microspheres and concept of targeting.
An overview of Microspheres including Advantages, Types, Method of preparation, Materials used in preparations, Characterization or Evaluation and Applications.
A note on Microsperes , general introduction and method of preparationsNEELAMSOMANI4
This presentation is related to Microspheres. Microspheres as a part of novel drug delivery system relevant to Pharmaceutics. The general introductions and methodology is described that will be helpful to all pharmacy students .
UNIT V
Mucoadhesive Delivery Systems:
Mechanism of bioadhesion, mucoadhesive materials, formulation and evaluation of Buccal and Nasal drug delivery systems.
I. INTRODUCTION
II. DEFINITIONS
III. TYPES OF DRUG MASTER FILES
IV. SUBMISSIONS TO DRUG MASTER FILES
V. AUTHORIZATION TO REFER TO A DRUG MASTER FILE
VI. PROCESSING AND REVIEWING POLICIES
VII. HOLDER OBLIGATIONS
IX. CLOSURE OF A DRUG MASTER FILE.
Introduction to Dissolution equipment's, Calibration of dissolution apparatus, Dissolution procedure development and validation, Dissolution method development for generic drug products.
Introduction and classification, anatomy of skin and factors affecting absorption, Formulation ,preparation, packaging, labeling and storage of ointments, Formulation, preparation, packaging, labeling and storage of jellies, creams, pastes.
Semisolid dosage forms: Definitions, classification, mechanisms and factors influencing dermal penetration of drugs. Preparation of ointments, pastes, creams and gels. Excipients used in semi solid dosage forms. Evaluation of semi solid dosages forms
Suspension, interfacial properties of suspended particles, settling in suspensions, formulation of flocculated and deflocculated suspensions. Emulsions and theories of emulsification, microemulsion and multiple emulsions; Stability of emulsions, preservation of emulsions, rheological properties of emulsions.
Historical background and development of profession of pharmacy: History of profession of Pharmacy in India in relation to pharmacy education, industry and organization, Pharmacy as a career, Pharmacopoeias: Introduction to IP, BP, USP and Extra Pharmacopoeia.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Anti ulcer drugs and their Advance pharmacology ||
Anti-ulcer drugs are medications used to prevent and treat ulcers in the stomach and upper part of the small intestine (duodenal ulcers). These ulcers are often caused by an imbalance between stomach acid and the mucosal lining, which protects the stomach lining.
||Scope: Overview of various classes of anti-ulcer drugs, their mechanisms of action, indications, side effects, and clinical considerations.
Factory Supply Best Quality Pmk Oil CAS 28578–16–7 PMK Powder in Stockrebeccabio
Factory Supply Best Quality Pmk Oil CAS 28578–16–7 PMK Powder in Stock
Telegram: bmksupplier
signal: +85264872720
threema: TUD4A6YC
You can contact me on Telegram or Threema
Communicate promptly and reply
Free of customs clearance, Double Clearance 100% pass delivery to USA, Canada, Spain, Germany, Netherland, Poland, Italy, Sweden, UK, Czech Republic, Australia, Mexico, Russia, Ukraine, Kazakhstan.Door to door service
Hot Selling Organic intermediates
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
2. INTRODUCTION
• Microspheres are solid spherical particles made up of polymeric
substances, in which the drug is dispersed through out the
microsphere matrix, its size ranges from 1-1000μm.
• Microcapsules are small particles that contain drug or core
material surrounded by a shell or coating of polymer.
There are two types
3. HISTORY
• The concept of packing microscopic
quantities of material with in
microspheres dates to 1930’s the
work of Bungenberg de Jong and
coworkers on the entrapment of
substance with coacervates.
• Use of micropsheres in industry
started in 1960`s.
4.
5. ADVANTAGES OF MICROSPHERES
1. They facilitate accurate delivery of small quantities of potent drug
and reduced concentration of drug at site other than the target organ
or tissue.
2. They provide protection for unstable drug before and after
administration, prior to their availability at the site of action.
3. They provide the ability to manipulate the in vivo action of the
drug, pharmacokinetic profile, tissue distribution and cellular
interaction of the drug.
4. They enable controlled release of drug. Ex: narcotic, antagonist,
steroid hormones.
5. Particle size reduction for enhancing solubility of the poorly
soluble drug.
6. Provide constant and prolonged therapeutic effect.
7. Provide constant drug concentration in blood there by increasing
patent compliance.
6. 9. Reduce the dosing frequency and thereby improve the patient
compliance
10.Better drug utilization will improve the bioavailability and reduce
the incidence or intensity of adverse effects.
11. Protects the GIT from irritant effects of the drug.
12. Biodegradable microspheres have the advantage over large
polymer implants in that they do not require surgical procedures
for implantation and removal.
13. Controlled release delivery biodegradable microspheres are used
to control drug release rates there by decreasing toxic side effects,
and eliminating the inconvenience of repeated injections.
14.Decrease dose and toxicity.
7. DISADVANTAGES
1. The costs of the materials and processing of the controlled release
2. preparation, are substantially higher than those of standard
formulations.
3. The fate of polymer matrix and its effect on the environment.
4. The fate of polymer additives such as plasticizers , stabilizers,
antioxidants and fillers.
5. Reproducibility is less.
6. Process conditions like change in temperature, pH, solvent
addition, and evaporation/agitation may influence the stability of
core particles to be encapsulated.
7. The environmental impact of the degradation products of the
polymer matrix produced in response to heat, hydrolysis,
oxidation, solar radiation or biological agents.
8. IDEAL CHARACTERISTICS of microspheres:
➢ The ability to incorporate reasonably high concentrations of the
drug.
➢ Stability of the preparation after synthesis with a clinically
acceptable shelf life.
➢ Controlled particle size and dispersability in aqueous vehicles
for injection.
➢ Release of active reagent with a good control over a wide time
scale.
➢ Biocompatibility with a controllable biodegradability.
➢ Susceptibility to chemical modification
9. Potential use of microspheres in the pharmaceutical
industry
• Taste and odour masking
• Conversion of oil and other liquids, facilitating ease of handling
• Protection of the drug from the environment
• Delay of volatilisation
• Freedom from incompatibilities between drug and excipients,
especially the buffers
• Improvement of flow properties
• Dispersion of water insoluble substance in aqueous media
• Production of sustained release, controlled release and targeted
medication
10. MICROSPHERE MANUFACTURE
Most important physicochemical characteristics that may
be controlled in microsphere manufacture are:
• Particle size and distribution
• Polymer molecular weight
• Ratio of drug to polymer
• Total mass of drug and polymer
11. MICROSPHERES PREPERATION METHODS
1) SINGLE EMULSION TECHNIQUE
2) DOUBLE EMULSION TECHNIQUE
3) POLYMERISATION TECHNIQUE
A) Normal Polymerisation
Bulk polymerisation
Suspension polymerisation
Emulsion polymerisation
B) Interfacial Polymerisation
4) COACERVATION PHASE SEPERATION
5) SPRAY DRYING & SPRAY CONGEALING
6) SOLVENT EXTRACTION
15. SUSPENSION POLYMERIZATION
▪ This is also referred as bead or pearl polymerization.
▪ It is carried out by heating the monomer or composition of
monomers as droplets dispersion in a continuous aqueous phase.
▪ Droplets may also contain an initiator and other additives
16.
17. INTERFACIAL POLYMERIZATION TECHNIQUE
This involves the reaction of various monomers at interface between
the two immiscible liquid phases to form a film of polymer.
Oil+ Monomer-A Water + Monomer-B
O/W Emulsion
• The monomers present in either phases diffuse rapidly and
polymerize rapidly at the interface.
• If the polymer is soluble in droplet it will lead to the formation of
the monolithic type of carrier.
• If the polymer is insoluble in monomer droplet, the formed carrier
is of capsular.
18. ADV & DISADV:
➢ Bulk polymerization forms pure polymer.
➢ In Bulk polymerization Heat of reaction affects
thermolabile drugs.
➢ Emulsion & suspension polymerization suitable for
thermolabile drugs.
➢ In Emulsion & suspension polymerization polymer
associates with unreacted monomer/ additives.
➢ Interfacial polymerization causes toxicity with
unreacted monomer.
➢ High permeability of film, fragile & non-biodegradable
microspheres.
➢ Drug degradation during polymerization
19. COACERVATION PHASE SEPERATION TECHNIQUE
• Specially designed for preparing reservoir type to encapsulate water soluble
drugs (proteins & peptides).
• For hydrophobic drugs (steroids) matrix type are designed.
Principle: solubility of polymer is decreased in organic phase to form polymer rich
phase called coacervates.
Addition of salt,
non-solvent,
incompatible
polymer,
pH change
20. SPRAY DRYING & SPRAY CONGEALING
Depending on the removal of solvent or cooling the solution are
named as “drying” and “congealing”, respectively.
Polymer dissolve in volatile organic solvent(acetone,DCM)
Drug dispersed in polymer solution under
high speed homogenization
Atomized in a stream of hot air
Solvent evaporation form small droplets
Leads to formation of Microspheres
Microspheres separated from hot air by cyclone separator,
Trace of solvent are removed by vacuum drying
Adv: Aseptic condition operation, Bulk manufacturing.
21.
22.
23.
24.
25. % Drug content = (amount of encapsulated drug
amount of added drug) *100
Surface carboxylic acid & amino acid residue:
Measured by using RADIOACTIVE GLYCINE.
C14 glycine ethyl ester hydrochloride + Microspheres ➔ Radioactive
glycine conjugate
C14 acetic acid + Microspheres ➔ Radioactive acid conjugate
Condensing agent – EDAC (1-ethyl-3(3-dimethyl aminopropyl)
carbidiimide)
Radioactivity is measured by using LIQUID SCINTILLATION COUNTER
26. APPLICATIONS
1. Vaccine delivery :
Improved antigenecity, Antigen controlled release, Stabilization of
Antigen. Ex: Diphtheria toxoid , Tetanus toxoid
2. Stability:
Microspheres are co-encapsulated with buffer salts, stabilizers.
Ex: triblock co-polymer (A-block = PLA/ PLAGA, B-block = PEO).
3. Antigen release:
Release of antigen in microspheres is influenced by structure, micro-
morphology, nature and type of polymer.
The release my follow burst mechanism, pore diffusion, erosion or
combination.
4. Microspheres and immune system:
Microsphere interaction with macrophages depends on particle size.
Microspheres < 10µ ➔ Antigen presenting cell ➔ Activate B&T cells.
Microspheres > 10µ ➔ degrade/ release antigen ➔ Antigen
presenting cell.
27.
28. 5. Targeting using microparticulate carriers:
a. Ocular:
rapid conversion of microparticulate suspension to gel leads to
longer retention time in eye.
b. Intranasal:
bioadhesive microspheres are used for delivery of proteins &
peptides.
c. Oral:
• multiple unit systems spreads over large area, avoid risk of dose
dumping.
• Oral route is suitable for soluble antigens.
• Anti-infective agents of poor aqueous solubility are
Incorporated in to pH sensitive microparticles.
• Attachment to ulcerated colonic tissue depends on size.
(10µ<1µ<0.1µ)
29. 6. Immuno-microsphere (MAB`s mediated targeting):
MAB`s are extremely specific molecules used to target selected sites.
MAB`s are directly attached by covalent coupling to the free aldehyde,
amino, hydroxy groups on microsphere surface.
MAB`s are attached to microsphere by following methods
1. Non-specific adsorption: (Vander waals-London forces)
MAB`s + Hydrophobic microspheres ➔ hydrophilic ➔ cell targeting.
2. Specific adsorption:
Microsphere + ligand + MAB ➔ Immuno-microsphere.
Ligands = avidin-biotin, Proteins-A form Staphylococcus aureus.
30. 3. Direct coupling:
Free functional groups on microspheres surface under go direct
coupling. Ex: Polyacroline microspheres (free carboxyl groups) +
MAB`s
4. Coupling via reagents:
Suitable when microspheres do not have free functional groups/
functional groups that do not bind. Carbodiimide method,
cyanogen bromide method, glutaraldehyde method, dextran
bridge method. etc.,
31. 7. Chemoembolization:
This is endovascular therapy, which involves selective arterial
embolization (blocking) of tumour together with local delivery of drug
loaded microspheres.
Blockade of arterioles and capillary bed of tumour has 2 benefits.
1. Increases time of absorption of drug at tumour site.
2. Blockage of blood supply causes ischemia & tumour regression.
microspheres of size > 40 µ are injected intra-arterially for
chemoembolization.
Ex: degradable starch microspheres are used for liver metastates.
32. 8. Microsponges- topical porous microspheres:
• Microsponges are porous microspheres having interconnected
voids of particle size range 5-300µ.
• Depending up on size pore length may range up to 10µ and pore
volume 1ml/g.
• These can entrap wide range of active ingredients such as
emollients, fragrances, essential oils, sunscreens and anti
infectives and used as topical carrier system.
• Microsponges can be formulated as creams, lotions, powders.
33. 9. Surface modified microspheres:
• This achieves targeting to discrete organs and to avoid rapid
clearance form the body by phagocytosis.
Ex: Poloxamer on surface of polystyrene/ PMMA microspheres ➔
more hydrophilic ➔ reduced macrophage uptake.
• PEG coated protein microspheres show decreased
immunogenecity.
• Surface modifiers = antibodies, proteins, polysaccharides,
chelating compounds, synthetic soluble polymers.
48. REFERENCES:
1. Targeted and controlled drug delivery novel carrier
system; SP. VYAS & RK.KHAR. 2010, CBS publishers.
2. Controlled and novel drug delivery; N.K.JAIN. 2017, CBS
publishers.
3. Introduction to novel drug delivery system; N.K.JAIN.
2017, Vallabh prakashan.
4. Textbook of industrial pharmacy, drug delivery system &
cosmetic and herbal drug technology. SHOBHA RANI. RH.
2014, universities press.