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A REVIEW ON RECENT ADVANCEMENT IN THE METHOD OF
PREPARATION OF NENOPARTICLES FOR THE ANTIMICROBIAL
BROAD SPECTRUM
Pawan Singh*1 and Prevesh Kumar
2
Assistant Professor, Department of Pharmacy Academy, IFTM University, Moradabad.
ABSTRACT
In the recent advancing trend in drug delivery system by nanoparticles.
In this trend the polymer and antibiotics drug delivery. The drug
stability and drug interaction is more important factor for a control and
perfect dug delivery. The achieving higher dose drug delivery in
systemic circulation and observed the higher systemic effect with the
lesser amount producing less side effect as compare other drug
delivery system. While large numbers of preclinical studies have been
published, the emphasis here is placed on preclinical and clinical
studies that are likely to affect clinical inquiries and their implications
for proceeding the treatment of patients with cancer and microbial
infection.
KEYWORDS: Nanoparticle, method of preparation, antimicrobial spectrum.
INTRODUCTION
Drug delivery System: Drug delivery is the method for administering a pharmaceutical
compound to achieve a therapeutic effect in humans or animals. Drug delivery system can
have very important role in efficacy of drugs.[1]
some drugs have an optimum concentration
of range within which maximum effect is derived. But there is very slow progress in efficacy
of the action of severe syndrome, has suggest a developing need of drug delivery system.[2]
Drug delivery system is multi-disciplinary approach to delivery of therapeutics to the target
tissue which gives new ideas on controlling the pharmacokinetics, pharmacodynamics,
immunogenicity, bio recognition, nonspecific toxicity and efficacy of the drug.[3]
Drug
delivery system (DDS) are based on interdisciplinary methodology that combine polymer
WORLD JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES
SJIF Impact Factor 6.041
Volume 5, Issue 7, 351-374. Review Article ISSN 2278 – 4357
*Corresponding Author
Pawan Singh
Assistant Professor,
Department of Pharmacy
Academy, IFTM
University, Moradabad.
Article Received on
08 May 2016,
Revised on 29 May 2016,
Accepted on 18 June 2016,
DOI: 10.20959/wjpps20167-6891
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science, pharmaceutics, molecular biology and bio conjugate chemistry. The main goal of
every drug delivery is to deliver the precise amount of drug on aim area. An essential guide
for biomedical engineers and pharmaceutical designers, this resource combines
physiochemical principles with physiological process to facilitate the design of the system
that will deliver drug at target area with exact time.[4]
The main approach of drug delivery
system is to promoting the exposure of drug on targeted area rather than non-target area to
avoid unnecessary side effects.
Novel drug delivery system is based on two mechanisms:
1. Physical mechanism
2. Biochemical mechanism
In physical mechanism include osmosis, diffusion, and erosion.
And in biochemical mechanism include monoclonal antibiotics, gene therapy, and vector
system. Drug delivery system (DDS) such as biodegradable polymer based nanoparticles can
be designed to improve drug bioavailability orally. There are many antibiotics, antifungal,
anticancer drugs which are recover by different drug delivery systems. DDS are designed to
alter the pharmacokinetics and bio circulation of the drug.[5]
The oral route remains the preferred to administrate drugs, but due to their physicochemical
and enzymatic barriers, they still have to be administered parentally. To overcome this, the
parental drugs release has been studied since few decades, which lead to the improvement of
numerous system, allowing an efficient system of compound to control release.[6]
Many types of drug delivery systems are in various stages of examination. These particles
have been architectures in such a way to ultimately lead to control and efficient release. Most
of the current research is mainly focusing on using nanoparticles as drug delivery carriers for
challenging to treat infectious and life binding syndrome.[7]
Using nanoparticles to carry
drug at target site lead to effective and efficient result.
Polymeric Nanoparticles and its classification
Conservative preparations like solution, suspension or emulsion suffer from certain limitations
like high dose and low availability, first pass effect, intolerance, instability, and they exhibit
fluctuations in plasma drug levels and do not provide sustained effect,[8]
therefore there is a
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need for some novel carriers which could meet ideal requirement of drug delivery system.
Recently nanoparticles delivery system has been proposed as colloidal drug carriers.[9]
Polymeric Nanoparticles (PNP) are defined as particulate dispersion or solid particles with a
size range of 10 to 1000 nm in diameter.[10]
The term PNP is a collective term given for any
type of polymer nanoparticle, but specifically for nanospheres and nanocapsules.
Nano spheres are matrix particles, i.e., particles whose entire mass is solid and molecules may
be adsorbed at the sphere surface or encapsulated within the particle. In general, they are
spherical, but ―nanospheres‖ with a nonspherical shape are also described in the literature.[11]
Nanocapsules are vesicular systems, acting as a kind of reservoir, in which the entrapped
substances are confined to a cavity consisting of a liquid core (either oil or water)
surrounded by a solid material shell.[12]
Nanoparticles may or may not exhibit size-related
properties that differ significantly from those observed in fine particles or bulk materials.
The major goal in designing of polymeric nanoparticles as a delivery system is,
1. To control particles size
2. Surface property
3. Release of pharmaceutical active agent in order to achieve in site design of drug at
therapeutically optical range and dose regimen
Drug release from nanoparticles
The nanoparticle is coated by polymer, which releases the drug by controlled diffusion or
erosion from the core across the polymeric membrane or matrix.[13]
The membrane coating
acts as a barrier to release, therefore, the solubility and diffusivity of drug in polymer
membrane becomes the determining factor in drug release.[14]
Furthermore release rate can
also be affected by ionic interaction between the drug and addition of auxiliary ingredients.
When the drug is involved in interaction with auxiliary ingredients to form a less water
soluble complex, then the drug release can be very slow with almost no burst release
effect.[15]
To develop a successful Nano particulate system, both drug release and polymer
biodegradation are important consideration factors.
In general, drug release rate depends on
(1) Solubility of drug, (2) Desorption of the surface bound/ adsorbed drug, (3) Drug diffusion
through the nanoparticle matrix, (4) Nanoparticle matrix erosion/degradation and (5)
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Combination of erosion/diffusion. Thus solubility, diffusion and biodegradation of the matrix
materials govern the release process
Preparation of biodegradable polymeric nanoparticles
The selection of appropriate method for the preparation of nanoparticles depends on the
physicochemical properties of the polymer and the drug to be loaded. The primary
manufacturing methods of nanoparticles from preformed polymer includes:
1. Emulsion solvent evaporation method.
2. Double Emulsion and Evaporation Method.
3. Salting out method.
4. Emulsion diffusion method.
5. Solvent displacement/precipitation method.
6. Ionic gelation method.
There are many other modified techniques used for preparation of biodegradable nanoparticles.
The key advantages of nanoparticles over other Nano carriers
1. Improved bioavailability by enhancing aqueous solubility,
2. Increasing resistance time in the body (increasing half-life for clearance/increasing
specificity for its cognate receptors.
3. Targeting drug to specific location in the body (its site of action).[16]
This results in
concomitant reduction in quantity of the drug required and dosage toxicity, enabling the
safe delivery of toxic therapeutic drugs and protection of non-target tissues and cells
from severe side effects. It is increasingly used in different submissions, including drug
carrier systems and to pass organ barriers such as the blood-brain barrier, cell membrane
etc. They are based on biocompatible lipid and provide sustained effect by either diffusion
or dissolution.[17]
4. When compared to single unit operation, multi-particulate systems such as nanoparticles
distributes more uniformly in GIT. Resulting in more uniform absorption and a bridged
danger of local irritation.
5. Nanoparticles shown to be more stable than liposomes in biological fluids and if
endocytosis of intact liposomes by the intestinal cells occurs at all, it remains a rare
event, thus limiting the potential applications of these carriers.[18]
The aim of drug
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targeting is to deliver drugs to the right place, at the high concentration, for the right
period of time.
Bacterial Infections
Bacteria are microscopic, single-celled organisms. There are thousands of different kinds, and
they live in every conceivable environment all over the world.[19]
They aware in soil,
seawater, and deep within the earth’s crust. Particular bacteria have been informed even to
live in radioactive waste. Many bacteria live in the bodies of people and animals—on the
skin and in the airways, mouth, and digestive, reproductive, and urinary tracts—without
affecting slightly detriment. Such bacteria are called occupier flora or the micro-biome.[20]
Many resident flora are actually helpful to people—for example by helping them digest food
or by preventing the growth of other, more hazardous bacteria.
Only a few kinds of bacteria cause disease. They are called pathogens. Sometimes bacteria
that normally reside inoffensively in the body cause disease. Bacteria can cause syndrome by
producing harmful substances (toxins), invading tissues, or doing both.[21]
Classification
The classification of bacteria serves a variety of different functions. Because of this variety,
bacteria may be grouped using many different typing schemes. The critical feature for all
these classification systems is an organism identified by one individual (scientist, clinician,
epidemiologist), is recognized as the same organism by another individual. At present the
typing schemes used by clinicians and clinical microbiologists rely on phenotypic typing
schemes. These schemes utilize the bacterial morphology and staining properties of the
organism, as well as O2 growth requirements of the species combined with a variety of
biochemical tests. For clinicians, the environmental reservoir of the organism, the vectors and
means of transmission of the pathogen are also of great importance. The classification
schemes most commonly used by clinicians and clinical microbiologists are discussed below.
Scientists interested in the evolution of microorganisms are more interested in taxonomic
techniques that allow for the comparison of highly conserved genes among different species.
A relatively new application of this technology has been the recognition and characterization
of non-cultivatable pathogens and the diseases that they cause.
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Phenotypic classification systems
Gram stain and bacterial morphology: Of all the different classification systems, the Gram
stain has withstood the test of time. Discovered by H.C. Gram in 1884 it remains an
important and useful technique to this day.[22]
It allows a large proportion of clinically
important bacteria to be classified as either Gram positive or negative based on their
morphology and differential staining properties. Slides are sequentially stained with crystal
violet, iodine, then destained with alcohol and counter-stained with safranin.[23]
Gram positive
bacteria stain blue-purple and Gram negative bacteria stain red. The difference between the
two groups is believed to be due to a much larger peptidoglycan (cell wall) in Gram positives.
As a result the iodine and crystal violet precipitate in the MID 1 thickened cell wall and are
not eluted by alcohol in difference with the Gram negatives where the crystal violet is readily
eluted from the bacteria. As a result bacteria can be famous based on their morphology and
staining properties.[24]
Some bacteria such as mycobacteria (the cause of tuberculosis) are not reliably stained due to
the large lipid content of the peptidoglycan. Alternative staining techniques (Kinyoun or acid
fast stain) are therefore used that take advantage of the resistance to de-staining after
lengthier initial staining. Bacteria can be classified in several ways:
Scientific names
Bacteria, like other living things, are classified by genus (based on having one or several
similar characteristics) and, within the genus, by species. Their scientific name is genus
followed by species (for example, Clostridium botulinum). Within a species, there may be
different types, called strains. Strains differ in genetic makeup and chemical components.
Sometimes certain drugs and vaccines are effective only against certain strains.
Staining
Bacteria may be classified by the color they turn after certain chemicals (stains) are applied
to them. A commonly used stain is the Gram stain. Some bacteria stain blue. They are called
gram-positive. Others stain red. They are called gram-negative. Gram-positive and gram-
negative bacteria stain inversely because their cell walls are different. They also cause
different types of infections, and different types of antibiotics are effective against them.
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Shapes
All bacteria may be classified as one of three basic shapes: spheres (cocci), rods (bacilli), and
spirals or helixes (spirochetes).
Fig: 1 shape of bacteria’s
Need for oxygen
Bacteria are also classified by whether they need oxygen to live and grow. Those that need
oxygen are called aerobes. Those that have trouble living or growing when oxygen is present
are called anaerobes. Some bacteria, called facultative bacteria, can live and grow with or
without oxygen.
Distinguishing Features between Gram Positive and Negative Bacteria
Gram positive bacteria have a large peptidoglycan structure. As noted above, this accounts for
the differential staining with Gram stain. Some Gram positive bacteria are also capable of
forming spores under stressful environmental conditions such as when there is limited
availability of carbon and nitrogen.[25]
Spores therefore allow bacteria to survive exposure to
extreme conditions and can lead to re-infection (e.g., pseudomembranous colitis from
Clostridium difficle).
Gram negative bacteria have a small peptidoglycan layer but have an additional membrane,
the outer cytoplasmic membrane. This creates an additional permeability barrier and results
in the need for transport mechanisms across this membrane.[26]
A major component of the cytoplasmic membrane that is unique to Gram negatives is
endotoxin. This component is essential for bacterial survival. Endotoxin has three
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components: the lipid A moiety, the highly conserved core polysaccharide, and the
species specific O antigen (also polysaccharide). In contrast with the secreted exotoxins,
endotoxin is cell-associated but can be released during cell division or cell death.[27]
The
Lipid A moiety of endotoxin is responsible for sepsis which may be fatal. Sepsis is
characterized clinically by confusion, fever, drop in blood pressure and ultimately multi-
organ failure.
Gram Positive Bacteria
Name Morphology O2
Requirements Commensal
Reservoirs/ Sites of
colonization,
Transmission
Types of
Infections
Staphylococci Cocci in grape
like clusters
facultative
anaerobe Yes
Skin, nares/endogenous,
direct contact, aerosol
Soft tissue, bone,
joint, endocarditis,
food poisoning
Streptococci
Cocci in pairs, chains
Facultative
anaerobe
Some
species
Oropharynx, skin/
endogenous, direct
contact, aerosol
Skin, pharyngitis,
endocarditis, toxic
shock
Pneumococci Diplococci,
lancet shaped
Facultative
anaerobe ±
Oropharynx, sinus /
aerosol
Pneumonia, otitis,
sinusitis,
meningitis
Enterococci Cocci in
pairs, chains
Facultative
anaerobe Yes
GI tract/ endogenous,
direct contact
UTI, GI,
catheterrelated
infections
Bacilli Rods,
sporeforming aerobic ±
Soil,air,water, animals
/aerosol, contact
Anthrax, food
poisoning,
catheter- related
infections
Clostridia Rods, spore
formers anaerobic
Some
species
GI tract, soil/Breach
of
Tetanus, diarrhea,
gas
skin,endogenous,
ingestion
gangrene,
botulism
Corynebacterium Rods, nonspore
forming
Facultative
anaerobe
Some
species
Skin Catheter- related
infections, diphtheria
Listeria
Meningitis
Rods,
nonspore formers
facultative
anaerobe No
Animals, food products
/ Meningitis
Actinomyces
Irregular,
filamentous, form
sulfur granules
anaerobic Yes GI tract/ endogenous Skin, soft tissue
Gram Negative Bacteria
Name Morphology O2
Requirements Commensal
Reservoirs /Sites of
colonization, Tr
ansmission
Types of
Infections
Enterobacteria
ceae (E. coli, Rods
facultative
anaerobe
Some
species
GI tract, animals/
Endogenous, fecaloral
Diarrhea, urinary
tract, food
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klebsiella,
salmonella,
shigella)
poisoning, sepsis
Bacteroides Rods anaerobic Yes GI tract/ Endogenous Abscesses,
intraabdomin al
infections
Pseudomonas Rods aerobic No
Water, soil/
Endogenous, breach of
skin barrier
Infections in
immunocomp ro
mised hosts,
Cystic Fibrosis
Vibrio (cholera) Rods, curved
shape
microaerophil
ic No
Water / Contaminated
food, water Diarrhea
Campylobacter Rods, curved
shape
microaerophil
ic No
Food / Ingestion
of contaminated food
Diarrhea,
Bacteremia
Legionella Rods, poorly
stained
microaerophil
ic No
Water/Inhalation of
aerosol
Pneumonia,
febrile illness
Neisseria Cocci, kidneybean
shaped Microaerophilic
No (N.
meningitidis
sometimes)
Humans/ Sexual,
aerosol
Meningitis,
pelvic
inflammatory
disease
Hemophilus Coccobacillary
- pleomorphic
Facultative
anaerobe
Some
species
Respiratory
tract/Endogenous,
aerosol
Respiratory,
sinusitis, otitis
meningitis
Bartonella Small,
pleomorphic rods
aerobic/
microaerophilic No
Cats, fleas, lice / cat
bites, lice or fleas?
Cat scratch
disease,
endocarditis,
bacillary
angiomatosis
Miscellaneous Bacteria
Name Morphology O2
Requirements Commensal
Reservoirs/Sites of
colonization,
Transmission
Types of
Infections
Helicobacter
GN, but not
visible on Gram
stain - helical
(corkscrew)
shaped
microaerophilic Yes Stomach/ Endogenous,
Fecal-oral
peptic ulcer
disease, gastric
ulcer
Mycobacteria
Rods, Weakly
Gram positive,
Acid fast stain
positive
aerobic No Lungs/Fomites Tuberculosis
Treponemes
Not visible on
Gram stain, spiral
shaped on dark
field exam
nonculturable
on
routine media
No Humans/ Sexual
transmission Syphilis
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Borrelia
Not visible on
Gram stain, spiral
shaped on dark
field exam
nonculturable
on routine
media
No Rodents, Ticks/ Tick
bites
Lyme, Relapsing
fever
Mycoplasma
Not visible on
Gram stain, no
cell wall,
pleomorphic
Non-culturable
on routine
media
Some
species Humans / aerosol
Respiratory tract
infections
Rickettsia/
Ehrlichia
Obligate
Intracellular
(Gram negative
but not visible on
Gram Stain)
Non-culturable
on routine
media
No
Ticks, Mites/transmitted
from the feces of
infected lice, fleas, ticks
Cause a variety
of illnesses
including
systemic
vasculitis
(e.g. Rocky
Mountain
Spotted Fever),
rash, pneumonia
Bacterial Defenses
Bacteria have many ways of defending themselves.
Biofilm
Some bacteria secrete a substance that helps them attach to other bacteria, cells, or objects.
This substance combines with the bacteria to form a sticky layer called biofilm. For example,
certain bacteria form a biofilm on teeth (called dental plaque). The biofilm traps food
particles, which the bacteria process and use, and in this process, they probably cause tooth
decay. Biofilms also help protect bacteria from antibiotics.
Capsules
Some bacteria are enclosed in a protective capsule. This capsule helps prevent white blood
cells, which fight infection, from ingesting the bacteria. Such bacteria are described as
encapsulated.
Outer membrane
Under the capsule, gram-negative bacteria have an outer membrane that protects them against
certain antibiotics. When disrupted, this membrane releases toxic substances called
endotoxins. Endotoxins contribute to the severity of symptoms during infections with gram-
negative bacteria.
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Spores
Some bacteria produce spores, which are an inactive (dormant) form. Spores can enable
bacteria to survive when environmental conditions are difficult. When conditions are
favorable, each spore germinates into an active bacterium.
Flagella
Flagella are long, thin filaments that protrude from the cell surface and enable bacteria to
move. Bacteria without flagella cannot move on their own.
Antibiotic resistance
Some bacteria are naturally resistant to certain antibiotics.
Other bacteria develop resistance to drugs because they acquire genes from other bacteria that
have become resistant or because their genes mutate.[28]
For example, soon after the drug
penicillin was introduced in the mid-1940s, a few individual Staphylococcus aureus bacteria
acquired genes that made penicillin ineffective against them.[29]
The strains that possessed
these special genes had a survival advantage when penicillin was commonly used to treat
infections. Strains of Staphylococcus aureus that lacked these new genes were killed by
penicillin, allowing the remaining penicillin-resistant bacteria to reproduce and over time
become more common.[30]
Chemists then altered the penicillin molecule, making a different
but similar drug, methicillin, which could kill the penicillin-resistant bacteria. Soon after
methicillin was introduced, strains of Staphylococcus aureus developed genes that made them
resistant to methicillin and related drugs. These strains are called methicillin-resistant
Staphylococcus aureus (MRSA).
The genes that encode for drug resistance can be passed to following generations of bacteria
or sometimes even to other species of bacteria.
The more often antibiotics are used, the more likely resistant bacteria are to develop.
Therefore, doctors try to use antibiotics only when they are necessary. Giving antibiotics to
people who probably do not have a bacterial infection,[31]
such as those who have cough and
cold symptoms, does not make people better but does help create resistant bacteria. Because
antibiotics have been so widely used (and misused), many bacteria are resistant to certain
antibiotics.
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Resistant bacteria can spread from person to person. Because international travel is so
common, resistant bacteria can spread to many parts of the world in a short time. Spread of
these bacteria in hospitals is a particular concern.[32]
Resistant bacteria are common in
hospitals because antibiotics are so often necessary and hospital personnel and visitors may
spread the bacteria if they do not strictly follow appropriate sanitary procedures. Also, many
hospitalized patients have a weakened immune system, making them more susceptible to
infection.[33]
Resistant bacteria can also spread to people from animals. Resistant bacteria are common
among farm animals because antibiotics are often routinely given to healthy animals to
prevent infections that can impair growth or cause illness.[34]
METHODS OF PREPARATION NANOPARTICLES FOR ANTIMICROBIAL
ACTION
Ionotropic gelation method
Ionotropic gelation is based on the ability of polyelectrolytes to cross link in the presence of
counter ions to form hydrogel beads also called as gelispheres. Gelispheres are spherical
crosslinked hydrophilic polymeric entity capable of extensive gelation and swelling in
simulated biological fluids and the release of drug through it controlled by polymer
relaxation.[35]
The hydrogel beads are produced by dropping a drug-loaded polymeric
solution into the aqueous solution of polyvalent cations.[36]
The cations diffuses into the
drug-loaded polymeric drops, forming a three dimensional lattice of ionically crosslinked
moiety. Biomolecules can also be loaded into these gelispheres under mild conditions to retain
their three dimensional structure .[37]
Polyelectrolyte solution
[Sodium Alginate (-)/Gellan gum (-)/CMC (-)/Pectin (-)/ Chitosan (+) + Drug]
↓
Added drop wise under magnetic stirring by needle
↓
Counter ion solution
[Calcium chloride solution (+)/Sodium tripolyphosphate (-)]
↓
Gelispheres
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In Ionotropic gelation technique, there has been a growing interest in the use of natural
polymers as drug carriers due to their biocompatibility and biodegradability.[38]
The natural
or semisynthetic polymers i.e. Alginates, Gellan gum, Chitosan, Pectin and Carboxymethyl
cellulose are widely use for the encapsulation of drug by this technique.[39]
These natural
polyelectrolytes contain certain anions/cations on their chemical structure, these
anions/cations forms meshwork structure by combining with the counter ions and induce
gelation by cross linking. In spite of having a property of coating on the drug core these
natural polymers also acts as release rate retardant.[40]
Ionic gelation technique presents the following advantages over other methods:
The nanoparticles are obtained spontaneously under mild control conditions without
involving high temperatures, organic solvents, or sonication. and TPP is a multivalent
polyanion, with low toxicity and cost, unlike other cross-linkers, it presents no severe
constraints of handling and storage. After adding TPP solution, nanoparticles form
immediately through inter and intramolecular linkages created between TPP phosphates and
EXP amino groups.
Natural polymers used in ionotropic gelation method- Alginates
Alginate is a non-toxic, biodegradable, naturally occurring polysaccharide obtained from
marine brown algae, certain species of bacteria. (41)Sodium alginate is a sodium salt of
alginic acid a natural polysaccharide and a linear polymer composed of 1,4-linked β-D-
Mannuronic acid (M) and α-D-gluronic acid (G) residues in varying proportions and
arrangements.[42]
Sodium alginate is soluble in water and form a reticulated structure which
can be cross-linked with divalent or polyvalent cations to form insoluble meshwork. Calcium
and zinc cations have been reported for cross-linking of acid groups of alginate.[43]
Gellan gum
Gellan gum is a bacterial exopolysaccharide prepared commercially by aerobic submerged
fermentation of Sphingomones Eloda.[44]
A concentrated water solution of gellan gum is
made warm up preliminary to induce the gellan gelation. When the temperature is decreased,
the chains undergo a conformational transition from random coils to double helicles (coil-
helix transition).[45]
Then rearrangement of a double helicles occurs leading to the formation
of ordered junction zones (sol-gel transition), thus giving a thermo-reversible hydrogel.[44]
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Chitosan
Chitosan is natural poly-(aminosaccharide), having structural characteristics similar to
glycosaminoglycans, is non-toxic and easily bioabsorbable.[46]
Chitosan due to its antacid
and antiulcer characteristics prevents or weakens drug irritation in the stomach.[47]
Chitosan
is a biopolymer which could be used for the preparation of various polyelectrolyte complex
products with natural polyanions such as xanthan, alginate, and carrangeenan.[48]
Among
these, complexes, chitosan-alginate complex may be the most important drug delivery
hydrogel system.
Carboxymethyl cellulose
The cellulose, a plant product on carboxymethylation process, can be modified as
carboxymethylcellulose (CMC).[49]
The interactions of the carboxylic groups of the CMC
with multivalent metal ions can be used to form so called ionotropic gels, which are
predominantly stabilized by the electrostatic interactions.[50]
In addition, interactions between
the –OH groups of the polymer and the metal ions contribute to the stability and the water
insolubility of these polymeric aggregates. The CMC can be cross-linked with
ferric/aluminum salt to get biodegradable hydrogel beads.[51]
Controlled release pattern can also be improved by coating these hydrogels with
chitosan/gelation and by cross-linking.
Pectin
Pectin is an inexpensive, non-toxic polysaccharide extracted from citrus peels or apple
pomaces, and has been used as a food additive,[52]
a thickening agent and a gelling agent.
Basically, it is a polymer of a-D-galacturonic acid with 1-4 linkages.
Factors affecting ionotropic gelation method[53]
1) Polymer and crosslinking electrolyte concentration
Polymer and electrolyte concentration have major effect on formulation of beads by
ionotropic gelation method. Concentration of both should in the ratio calculated from number
of crosslinking units. Percent entrapment efficiency varies from the type of electrolytes
and also the concentration of electrolytes.
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2) Temperature
Temperature also plays imp role on size of beads formed by ionotropic gelation method and
also on the curing time i.e. time required for crosslinking.
3) pH of crosslinking solution
pH of crosslinking solution also considerable factor during the formulation as it shows effect
on reaction rate, shape and size of beads.
4) Drug concentration
Drug to be entrapped in the beads should be in the proper ratio with the polymer, as the drug
concentration greatly affects the entrapment efficiency, if drug: polymer ratio exceeds the
range then bursting effect may observe, density of gelispheres enhances and the size and
shape of gelispheres also increases.
5) Gas forming agent concentration
Gas forming agents such as calcium carbonate, sodium bicarbonate added in to the
formulation to develop porous gelispheres, which tremendously affect the gelispheres size
and shape. As gas forming agent forms porous gelispheres, breaks the lining of gelispheres
and results into the irregular surface.
Advances in Ionotropic gelation[54]
1) Polyelectrolyte complexation technique/ Ionotropic pre-gelation
The quality of hydrogel beads prepared by ionotropic gelation method can also be further
improved by polyelectrolyte complexation technique.[53]
The mechanical strength and
permeability barrier of hydrogels can be improved by the addition of oppositely charged
another polyelectrolyte to the ionotropically gelated gelispheres. For instance, addition of
polycations allows a membrane of polyelectrolyte complex to form on the surface of alginate
gelispheres. Authors Anil K. Anal, Willem F. Stevens reported a method for polyelectrolyte
beads of ampicillin prepared by ionotropic gelation method. Authors selected alginate and
chitosan for complexation and reported enhancement in encapsulation efficiency and
improved properties of controlled release of formed multilayer ampicillin.
2) Ionotropic gelation under a high voltage electrostatic field
Authors Lihua Ma and Changsheng Liu reported a modified ionotropic gelation method by
combining it with a high voltage electrostatic field to prepare protein-loaded chitosan
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microspheres. This is new method for sustain delivery of Bovine Serum Albumin (BSA) by
encapsulating in chitosan microsphere also reported that the microspheres exhibited good
sphericity and dispersibility when the mixture of sodium tripolyphosphate (TPP) and ethanol
was applied as coagulation solution.[55]
The results from the literature survey suggest that
ionotropic gelation method combined with a high voltage electrostatic field is an effective
method for sustained delivery of protein by gelispheres.
3) Emulsion-internal ionotropic gelation
It is the advanced method in ionotropic gelation with the incorporation of oily phase and
emulsifier. As reported by Singla and colleagues the dispersed phase consisting of 40 mL of
2% v/v aqueous acetic acid containing 2.5% w/v chitosan was added to the continuous phase
consisting of hexane (250 mL) and Span 85 (0.5% w/v) to form a w/o emulsion. After 20
minutes of mechanical stirring, 15 mL of 1N sodium hydroxide solution was added at the rate
of 5mL per min at 15min intervals. Stirring speed of 2000 to 2200 rpm was continued for 2.5
hours. The microspheres were separated by filtration and subsequently washed with
petroleum ether, followed by distilled water and then air dried.[56]
Also Anita G. Sullad, Lata
S. Manjeshwar and Tejraj M. Aminabhav developed microspheres of Abacavir sulfate by w/o
emulsion method using Carboxy methyl guar gum, an anionic synthetic derivative.
Author Deepak singh and his colleagues developed Dry Powder Inhalation system of
Terbutaline sulfate for management of Asthma and the microspheres of Terbutaline sulfate
prepared by emulsification-ionotropic gelation and heat crosslinking agent. According to this
method aqueous solutions of chitosan and Terbutaline sulfate (in 0.5% acetic acid) were
emulsified in oil phase (100-200ml) consisting of dichloromethane and light liquid paraffin
(LLP) using homogenizer for 15 min. Span 80 was used as an emulsifier and lecithin as a co-
emulsifier and deaggregating agent. Cross-linking solution (citric acid, tripolyphosphate and
glucose 1%; 5-15 ml) was added to this emulsion and homogenization was continued for
another 30 min. This emulsion was then added slowly to light liquid paraffin (50 ml) which
was previously heated and maintained at 120° ± 10°C with continuous stirring for another one
hour. The hot oily dispersion of microspheres was then allowed to cool to room temperature
with continuous stirring at same speed, and finally centrifuged on a high-speed centrifuge at
10000 rpm for 10 min, in order to separate the microspheres. The sediment was dispersed in
diethyl ether to remove the oil, and this dispersion was again centrifuged for 3 min at the same
speed. Washing with diethyl ether was repeated three more times in a similar manner to
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Singh et al. World Journal of Pharmacy and Pharmaceutical Sciences
remove traces of oil. The sediment thus obtained was dried in oven at 50°-60°C, passed
through 100-mesh sieve and stored.
w/o/w emulsion solvent evaporation containing ionotropic gelation is the modified technique
involving multiphase. This method draws more attention nowadays, as the method is useful
for encapsulation of water-soluble drugs, proteins, DNA or antigens into microsphere or
nanosphere as effective delivery carriers.
4) Ionotropic gelation followed by coacervation
Jaejoon Han, Anne-sophie Guenier and colleagues successfully developed a new
encapsulation method involving two polymers (alginate and chitosan) and using methods of
functionalization (acylation) and ionotropic gelation followed coacervation to improve the
stability and physicochemical properties of beads. Beads were formed by ionotropic gelation
via calcium cross- linking and by alginate-chitosan complex coacervation. The main
difference between native and functionalized beads consisted in the presence of fatty acid
chains in the core (palmitoylated alginate) and external layer (palmitoylated chitosan) of
beads. Hence, alginate cross-links improved insolubility of beads by ionotropic gelation and
alginate-chitosan coacervation, which led to polyionic links between the core bead and the
external layer. Functionalization increases hydrophobic interactions into polymeric matrix
involving structural changes also improves the polymers barrier property by decreasing water
uptake and Water vapour pressure. Functionalized polymers did not improve their mechanical
properties and stability of micronutrients encapsulated in native and functionalized beads.
Authors also demonstrated that encapsulation had an excellent capacity to protect bioactive
molecules against temperature, humidity, and acidic conditions and allowed a controlled
release of these compounds during gastrointestinal transit.
C.L. Gerez, G. Font de Valdez and colleagues also developed novel microencapsulation of
Lactobacillus rhamnosus by ionotropic gelation using pectin (PE) and pectin-whey protein
(PE- WP). Both types of beads were covered with a layer of whey protein by complex
coacervation to improve the survival rate of Lactobacillus rhamnosus in Gastric fluid.
5) Alginate-Poly (ethylene glycol) Hybrid Gelispheres
A new type of hydrogel microspheres was synthesized by Redouan Mahou and Christine
Wandrey, according to them the combination of electrostatic interaction of calcium ions with
sodium alginate and the chemical reaction of vinyl sulfone-terminated poly (ethylene glycol)
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Singh et al. World Journal of Pharmacy and Pharmaceutical Sciences
(PEG-VS) with Threo-1,4-dimercapto-2,3-butanediol (DTT). A one-step extrusion process
under physiological conditions yielded calcium alginate-poly (ethylene glycol) hybrid
microspheres (Alg-PEG-M), an interpenetrating network with well-controllable physical
properties. It was mentioned that the permeability of the hydrogel can be tailored by
adequate choice of the arm length of PEG-VS, while the swelling degree can be tuned by
varying the PEG-VS concentration and/or by liquefaction of Calcium-alginate. It was also
given that dissolution of Calcium alginate has no significant impact on the mechanical
resistance of the obtained Poly (ethylene glycol) microspheres (PEG-M). Overall, important
physical properties of the hydrogel spheres are obtainable in the range desired for
biotechnological, biomedical, and pharmaceutical applications.
6) Multi-polyelectrolyte gelispheres
Viness Pillay, Michael P. Danckwerts statistically developed and evaluated calcium-alginate-
pectinate-cellulose acetophthalate gelisphere. Authors focus on the the complex dynamics
associated with the three key textural parameters namely matrix resilience, fracture energy,
and matrix hardness which were significantly influenced by the degree of crosslinking
achieved under various conditions of reaction.
In this technique the polymer solution for crosslinking prepared as: 1.5 g of disodium
hydrogen orthophosphate was dissolved in 80 mL of deionized water to which cellulose
acetophthalate (1.5% w/v) was added. To facilitate dissolution of cellulose acetophthalate,
the solution was magnetically stirred at 658°C, taking precautions not to introduce air
bubbles. Thereafter, sodium alginate and pectin (1.5% w/v each) was added to this solution.
This multicomponent solution was then made up to volume 100 mL with deionized water.
The crosslinking solution was prepared by dissolving 150mL of glacial acetic acid in 1000
mL of deionized water. To this acidified solution, 2% w/v calcium chloride was incorporated.
Gelispheres were formed by titration of the polymer suspension at 2 mL/min with the
crosslinking solution using flat-tip 19-guage opening. The gelispheres formed were
allowed to cure for period of 24 hour at 218°C, then the crosslinking solution decanted and
gelispheres washed and dried for 48 hour at 218°C under extractor.
7) Ionotropic gelation followed by compression
Yahya E. Choonara and colleagues developed a new method for Alginate-
Hydroxyethylcellulose Gelispheres for Controlled Intrastriatal Nicotine Release in
Parkinson’s disease. Hydroxyethylcellulose was incorporated as a reinforcing protective
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colloidal polymer to induce interactions between the free carboxyl groups of alginate with
Hydroxy ethyl cellulose monomers. Further to prolong the release of nicotine, Gelispheres
were compressed within an external poly (lactic-co-glycolic acid) (PLGA) matrix.
CONCLUSION
The study of nanoparticle about most achieving drug delivery for antimicrobial activity
showing higher systemic effect. The Nanoparticles in the size range 1–100 nm are developing
as a class of therapeutics for cancer and antimicrobial spectrum. Nanoparticles therapeutics
can show enhanced effectiveness, while concurrently reducing side effects, owing to
properties such as more targeted localization in tumours, active cellular uptake and
antimicrobial spectrum. Application of nanoparticles in these arenas is dependent on the
ability to production particles with different chemical conformation, shape, size, and
monodispersity. In the preparation of nanoparticles are using biodegradable polymer and
advantage of bio readable polymer they shall have lesser side effect as compare to other
polymer. In the preparation methods are archiving by using different polymers and different
solvents.
REFERENCES
1. Bernabeu E, Gonzalez L, Cagel M, Gergic EP, Moretton MA, Chiappetta DA. Novel
Soluplus-TPGS mixed micelles for encapsulation of paclitaxel with enhanced in vitro
cytotoxicity on breast and ovarian cancer cell lines. Colloids and surfaces B, Biointerfaces,
2016; 140: 403-11.
2. Utku S, Ozcanhan MH, Suleyman M. Automated personnel-assets-consumables-drug
tracking in ambulance services for more effective and efficient medical emergency
interventions. Computer methods and programs in biomedicine, 2016.
3. Sherafudeen SP, Vasantha PV. Development and evaluation of in situ nasal gel
formulations of loratadine. Research in pharmaceutical sciences, 2015; 10(6): 466-76.
4. Mehanny M, Hathout RM, Geneidi AS, Mansour S. Exploring the use of nanocarrier
systems to deliver the magical molecule; Curcumin and its derivatives. Journal of
controlled release: official journal of the Controlled Release Society, 2016.
5. Kang X, Xiao HH, Song HQ, Jing XB, Yan LS, Qi RG. Advances in drug delivery system
for platinum agents based combination therapy. Cancer biology & medicine, 2015; 12(4):
362-74.
www.wjpps.com Vol 5, Issue 7, 2016.
370
Singh et al. World Journal of Pharmacy and Pharmaceutical Sciences
6. Jeon H, Kim J, Lee YM, Kim J, Choi HW, Lee J, et al. Poly-paclitaxel/cyclodextrin-SPION
nano-assembly for magnetically guided drug delivery system. Journal of controlled
release: official journal of the Controlled Release Society, 2016.
7. El-Sherbiny IM, El-Baz NM, Yacoub MH. Inhaled nano- and microparticles for drug
delivery. Global cardiology science & practice, 2015; 2015: 2.
8. Choi GH, Rhee DK, Park AR, Oh MJ, Hong S, Richardson JJ, et al. Ag
Nanoparticle/Polydopamine-Coated Inverse Opals as Highly Efficient Catalytic
Membranes. ACS applied materials & interfaces, 2016.
9. Mattos AC, Altmeyer C, Tominaga T, Khalil NM, Mainardes RM. Polymeric nanoparticles
for oral delivery of 5-fluorouracil: Formulation optimization, cytotoxicity assay and pre-
clinical pharmacokinetics study. European journal of pharmaceutical sciences: official
journal of the European Federation for Pharmaceutical Sciences, 2016.
10. Lim WK, Denton AR. Depletion-induced forces and crowding in polymer-nanoparticle
mixtures: Role of polymer shape fluctuations and penetrability. The Journal of chemical
physics, 2016; 144(2): 024904.
11. Karimi M, Ghasemi A, Sahandi Zangabad P, Rahighi R, Moosavi Basri SM, Mirshekari
H, et al. Smart micro/nanoparticles in stimulus-responsive drug/gene delivery systems.
Chemical Society reviews, 2016.
12. Holmkvist AD, Friberg A, Nilsson UJ, Schouenborg J. Hydrophobic ion pairing of a
minocycline/Ca/AOT complex for preparation of drug-loaded PLGA nanoparticles with
improved sustained release. International journal of pharmaceutics, 2016.
13. Jogala S, Rachamalla SS, Aukunuru J. Development of PEG-PLGA based intravenous low
molecular weight heparin (LMWH) nanoparticles intended to treat venous thrombosis.
Current drug delivery, 2016.
14. Jenkins SI, Weinberg D, Al-Shakli AF, Fernandes AR, Yiu HH, Telling ND, et al. 'Stealth'
nanoparticles evade neural immune cells but also evade all major brain cell populations:
Implications for PEG-based neurotherapeutics. Journal of controlled release: official
journal of the Controlled Release Society, 2016.
15. Ghasemi A, Mohtashami M, Sheijani SS, Aliakbari K. Chitosan-genipin nanohydrogel as
a vehicle for sustained delivery of alpha-1 antitrypsin. Research in pharmaceutical
sciences, 2015; 10(6): 523-34.
16. Yu C, Zhou M, Zhang X, Wei W, Chen X, Zhang X. Smart doxorubicin nanoparticles with
high drug payload for enhanced chemotherapy against drug resistance and cancer
diagnosis. Nanoscale, 2015; 7(13): 5683-90.
www.wjpps.com Vol 5, Issue 7, 2016.
371
Singh et al. World Journal of Pharmacy and Pharmaceutical Sciences
17. Wang H, Zhao Y, Wu Y, Hu YL, Nan K, Nie G, et al. Enhanced anti-tumor efficacy by co-
delivery of doxorubicin and paclitaxel with amphiphilic methoxy PEG-PLGA copolymer
nanoparticles. Biomaterials, 2011; 32(32): 8281-90.
18. Shen Y, Jin E, Zhang B, Murphy CJ, Sui M, Zhao J, et al. Prodrugs forming high drug
loading multifunctional nanocapsules for intracellular cancer drug delivery. Journal of the
American Chemical Society, 2010; 132(12): 4259-65.
19. de Sa Del Fiol F, Barberato-Filho S, de Cassia Bergamaschi C, Lopes LC, Gauthier TP.
Antibiotics and Breastfeeding. Chemotherapy, 2016; 61(3): 134-43.
20. Courtney CM, Goodman SM, McDaniel JA, Madinger NE, Chatterjee A, Nagpal P.
Photoexcited quantum dots for killing multidrug-resistant bacteria. Nature materials, 2016.
21. Andreini P, Bonechi S, Bianchini M, Garzelli A, Mecocci A. Automatic image
classification for the urinoculture screening. Computers in biology and medicine, 2016;
70: 12-22.
22. Verma A, Leader JB, Verma SS, Frase A, Wallace J, Dudek S, et al. Integrating Clinical
Laboratory Measures and Icd-9 Code Diagnoses in Phenome-Wide Association Studies.
Pacific Symposium on Biocomputing Pacific Symposium on Biocomputing, 2016; 21:
168-79.
23. Thrall JH. Moreton Lecture: Imaging in the Age of Precision Medicine. Journal of the
American College of Radiology: JACR, 2015; 12(10): 1106-11.
24. Shilovsky GA, Putyatina TS, Markov AV, Skulachev VP. Contribution of Quantitative
Methods of Estimating Mortality Dynamics to Explaining Mechanisms of Aging.
Biochemistry Biokhimiia, 2015; 80(12): 1547-59.
25. Martiny JB, Jones SE, Lennon JT, Martiny AC. Microbiomes in light of traits: A
phylogenetic perspective. Science, 2015; 350(6261): aac9323.
26. Kerr IB, Finlayson-Short L, McCutcheon LK, Beard H, Chanen AM. The 'Self' and
Borderline Personality Disorder: Conceptual and Clinical Considerations.
Psychopathology, 2015; 48(5): 339-48.
27. Dawson AM, Bettgenhaeuser J, Gardiner M, Green P, Hernandez-Pinzon I, Hubbard A, et
al. The development of quick, robust, quantitative phenotypic assays for describing the
host-nonhost landscape to stripe rust. Frontiers in plant science, 2015; 6: 876.
28. De la Calle C, Morata L, Cobos-Trigueros N, Martinez JA, Cardozo C, Mensa J, et al.
Staphylococcus aureus bacteremic pneumonia. European journal of clinical microbiology
& infectious diseases: official publication of the European Society of Clinical
Microbiology, 2016.
www.wjpps.com Vol 5, Issue 7, 2016.
372
Singh et al. World Journal of Pharmacy and Pharmaceutical Sciences
29. Zhou YF, Shi W, Yu Y, Tao MT, Xiong YQ, Sun J, et al.
Pharmacokinetic/Pharmacodynamic Correlation of Cefquinome Against Experimental
Catheter-Associated Biofilm Infection Due to Staphylococcus aureus. Frontiers in
microbiology, 2015; 6: 1513.
30. Steyn M, Buskes J. Skeletal Manifestations of TB in Modern Human Remains. Clinical
anatomy, 2016.
31. Silva-Valenzuela CA, Molina-Quiroz RC, Desai P, Valenzuela C, Porwollik S, Zhao M, et
al. Analysis of Two Complementary Single-Gene Deletion Mutant Libraries of Salmonella
Typhimurium in Intraperitoneal Infection of BALB/c Mice. Frontiers in microbiology,
2015; 6: 1455.
32. Sigurdsson S, Kristinsson KG, Erlendsdottir H, Hrafnkelsson B, Haraldsson A. Decreased
Incidence of Respiratory Infections in Children After Vaccination with Ten-valent
Pneumococcal Vaccine. The Pediatric infectious disease journal, 2015; 34(12): 1385-90.
33. Shahi SK, Kumar A. Isolation and Genetic Analysis of Multidrug Resistant Bacteria from
Diabetic Foot Ulcers. Frontiers in microbiology, 2015; 6: 1464.
34. Nam EY, Song KH, Kim NH, Kim M, Kim CJ, Lee JO, et al. Differences in characteristics
between first and breakthrough neutropenic fever after chemotherapy in patients with
hematologic disease. International journal of infectious diseases: IJID: official publication
of the International Society for Infectious Diseases, 2016.
35. Xu JH, Dai WJ, Chen B, Fan XY. Mucosal immunization with PsaA protein, using chitosan
as a delivery system, increases protection against acute otitis media and invasive infection
by Streptococcus pneumoniae. Scandinavian journal of immunology, 2015; 81(3): 177-
85.
36. Siddhapura K, Harde H, Jain S. Immunostimulatory effect of tetanus toxoid loaded
chitosan nanoparticles following microneedles assisted immunization. Nanomedicine:
nanotechnology, biology, and medicine, 2015.
37. Sher P, Oliveira SM, Borges J, Mano JF. Assembly of cell-laden hydrogel fiber into non-
liquefied and liquefied 3D spiral constructs by perfusion-based layer-by-layer technique.
Biofabrication, 2015; 7(1): 011001.
38. Shah HA, Patel RP. Statistical modeling of zaltoprofen loaded biopolymeric nanoparticles:
Characterization and anti-inflammatory activity of nanoparticles loaded gel. International
journal of pharmaceutical investigation, 2015; 5(1): 20-7.
www.wjpps.com Vol 5, Issue 7, 2016.
373
Singh et al. World Journal of Pharmacy and Pharmaceutical Sciences
39. Seelan V, Kumari HL, Kishore N, Selvamani P, Thanzami K, Pachuau L, et al. Exploitation
of novel gum Prunus cerasoides as mucoadhesive beads for a controlled-release drug
delivery. International journal of biological macromolecules, 2016.
40. 40. Sarwar A, Katas H, Samsudin SN, Zin NM. Regioselective Sequential
Modification of Chitosan via Azide-Alkyne Click Reaction: Synthesis, Characterization,
and Antimicrobial Activity of Chitosan Derivatives and Nanoparticles. PloS one, 2015;
10(4): e0123084.
41. 41. Coluccino L, Stagnaro P, Vassalli M, Scaglione S. Bioactive TGF-beta1/HA
alginate- based scaffolds for osteochondral tissue repair: design, realization and
multilevel characterization. Journal of applied biomaterials & functional materials, 2015:
0.
42. Szekalska M, Winnicka K, Czajkowska-Kosnik A, Sosnowska K, Amelian A. Evaluation
of Alginate Microspheres with Metronidazole Obtained by the Spray Drying Technique.
Acta poloniae pharmaceutica, 2015; 72(3): 569-78.
43. Rembe JD, Bohm JK, Fromm-Dornieden C, Schafer N, Maegele M, Frohlich M, et al.
Comparison of hemostatic dressings for superficial wounds using a new
spectrophotometric coagulation assay. Journal of translational medicine, 2015; 13: 375.
44. Jamshidi P, Birdi G, Williams RL, Cox SC, Grover LM. Modification of gellan gum with
nanocrystalline hydroxyapatite facilitates cell expansion and spontaneous osteogenesis.
Biotechnology and bioengineering, 2015.
45. Moxon SR, Smith AM. Controlling the rheology of gellan gum hydrogels in cell culture
conditions. International journal of biological macromolecules, 2015; 84: 79-86.
46. Hosseinnejad M, Jafari SM. Evaluation of different factors affecting antimicrobial
properties of chitosan. International journal of biological macromolecules, 2016.
47. Yao M, Zhou Y, Xue C, Ren H, Wang S, Zhu H, et al. Repair of rat sciatic nerve defect by
using allogeneic bone marrow mononuclear cells combined with chitosan/silk fibroin
scaffold. Cell transplantation, 2016.
48. Yang CH, Wang LS, Chen SY, Huang MC, Li YH, Lin YC, et al. Microfluidic assisted
synthesis of silver nanoparticle-chitosan composite microparticles for antibacterial
applications. International journal of pharmaceutics, 2016.
49. Laffleur F, Bacher L, Vanicek S, Menzel C, Muhammad I. Next generation of
buccadhesive excipient: preactivated carboxymethyl cellulose. International journal of
pharmaceutics, 2016.
www.wjpps.com Vol 5, Issue 7, 2016.
374
Singh et al. World Journal of Pharmacy and Pharmaceutical Sciences
50. Wu H, Li GN, Xie J, Li R, Chen QH, Chen JZ, et al. Resveratrol ameliorates myocardial
fibrosis by inhibiting ROS/ERK/TGF-beta/periostin pathway in STZ-induced diabetic
mice. BMC cardiovascular disorders, 2016; 16(1):5.
51. Vimalraj S, Saravanan S, Vairamani M, Gopalakrishnan C, Sastry TP, Selvamurugan N. A
Combinatorial effect of carboxymethyl cellulose based scaffold and microRNA-15b on
osteoblast differentiation. International journal of biological macromolecules, 2016.
52. Miran W, Nawaz M, Jang J, Lee DS. Conversion of orange peel waste biomass to
bioelectricity using a mediator-less microbial fuel cell. The Science of the total
environment, 2016; 547: 197-205.
53. Jain NK, Jain SK. Development and in vitro characterization of galactosylated low
molecular weight chitosan nanoparticles bearing doxorubicin. AAPS Pharm Sci Tech,
2010; 11(2): 686-97.
54. Vaezifar S, Razavi S, Golozar MA, Karbasi S, Morshed M, Kamali M. Effects of Some
Parameters on Particle Size Distribution of Chitosan Nanoparticles Prepared by Ionic
Gelation Method. Journal of Cluster Science, 2013; 24(3): 891-903.
55. Ma L, Liu C. Preparation of chitosan microspheres by ionotropic gelation under a high
voltage electrostatic field for protein delivery. Colloids and surfaces B, Biointerfaces,
2010; 75(2): 448-53.
56. Shu XZ, Zhu KJ. Chitosan/gelatin microspheres prepared by modified emulsification and
ionotropic gelation. Journal of microencapsulation, 2001; 18(2): 237-45.