Aquasomes
1st M-Pharm

Pharmaceutics dept

college of pharmacy

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Definition of aquasome
 Aquasomes are nanoparticulate carrier system

but instead of being simple nanoparticles these
are three layered self assembled structures,
comprised of a solid phase nanocrystalline core
coated with oligomeric film to which
biochemically active molecules are absorbed
with or without modification.

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 Aquasomes are first discovered by nir kossovsky.

 These carbohydrate stabilize nanoparticles of
ceramic are known as aquasomes which was
first developed in 1995.

 Aquasome consists of a solid crystalline core,
carbohydrate coat and active drug.

 The solid core provides the structural stability,
while the carbohydrate coating plays an
important role as a natural stabilizer protects
against dehydration and stabilizes the
biochemically active molecule.

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 Aquasomes are spherical 60-300 nm particles.
 Aquasomes offer an attractive mode of delivery

for drugs which having the problems such as
route of delivery ,physical as well as chemical
stability, poor bioavailability and potent side
effects.

 Aquasomes are like “bodies of water” and their
water like properties protect and preserve
fragile biological molecules, and this property of
maintaining conformational integrity as well as
high degree of surface exposure is exploited in
targeting of bio-active molecules like peptide
and protein hormones,enzymes,antigens and
genes to specific sites.

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 COMPOSITION OF AQUASOMES

 Core material – Ceramic and polymers are most
widely used core materials. Polymers such as
albumin, gelatin or acrylate used. Ceramic such
as diamond particles, brushite (calcium
phosphate)and tin oxide are used.

 Coating material- Coating materials commonly
used are cellobiose ,pyridoxal 5 phosphate,
sucrose, trehalose, chitosan, citrate etc.

 Carbohydrate plays important role act as
natural stabilizer, its stabilization efficiency has
been reported.

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 Beginning with preformed carbon ceramic
nanoparticle and self assembled calcium
phosphate dihydrate particles (colloidal
precipitation) to which glassy carbohydrate are
then allowed to adsorb as a nanometer thick
surface coating a molecular carrier is formed.

 Bioactive – They have the property of interacting
with film via non covalent and ionic interactions.

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 Formulation of aquasomes

Principles of self assembly of macromolecules :

 These three layered structure are self assembled
by non covalent bonds.

 It is comprised of three physicochemical process
i.e

1. Interaction between charged group

2. Hydrogen bonding and dehydration effect.

3. Structural stability.

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 Interaction between charged groups:

the interaction of charged group facilitates
long range approach of self assembly sub units
charge group also playa a role in stabilizing
teritary structures of folded proteins.

 Hydrogen bonding and Dehydration effects:

Hydrogen bond helps in base pair matching
and stabilization secondary protein such as alpha
helices and beta sheets.

In case of hydrophobic molecules due to the
dehydration effect they can self assembled.

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 Structural stability:

structural stability of protein in biological
environment determined by interaction between
charged group and hydrogen bonds largely
external to molecule and by van der waals
forces largely internal to molecule experienced
by hydrophobic molecules, responsible for
harness and softness of molecule and by
maintaining of internal secondary strructures,
provides sufficient softness allows maintenance
of conformation during self assembly.

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Role of disaccharides:

Among three layers of aquasomes, carbohydrate
fulfills the objective of aquasomes. The hydroxyl
groups on oligomer interact with polar and
charged groups of proteins, in a same way as with
water thus preserve the aqueous structure of
proteins on dehydration. The most commonly
used carbohydrates are cellobiose, pyridoxal-5-
phosphate, trehalose, sucrose, citrates etc.

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Method of preparation

 By using the principle of self assembly
aquasomes can be prepared by three
method.

1. Preparation of core

2. Coating of core

3. Immobilization of drug molecule.

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 Preparation of core: this stage mainly depends
on the

➢ selection of material for core and by its
physical chemical properties.

➢ This can be fabricated by the sonication
method and colloidal preparation.

➢ For the core material ceramic material is widely
used as they are structurally to be known.

➢ Commonly used ceramic core are tin oxide
and calcium phosphate.

➢ Example:
a) Synthesis of nanocrystalline tin oxide core

material: which can be prepared by direct
current reactive and magnetron sputtering

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 Here, a 3 inches diameter target of high purity
tin is sputtered in a high pressure gas mixture of
orgon and oxygen. The ultrafine particles
formed in the gas phase are then collected on
copper tubes cooled to 770K with flowing
nitrogen.

Self assembled nanocrystalline brushite (calcium
phosphate dihydrate): These can be prepared by
colloidal precipitation and sonication by reacting
solution of disodium hydrogen phosphate and
calcium chloride.

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 Coating of the core: with polyhydroxy oligomer: In
the second step, ceramic cores are coated with
carbohydrate (polyhydroxyl oligomer).

 The coating is carried out by addition of
carbohydrate into an aqueous dispersion of the
cores under sonication.

 These are then subjected to lyophilization to
promote an irreversible adsorption of
carbohydrate onto the ceramic surface. The
unadsorbed carbohydrate is removed by
centrifugation.

 The commonly used coating materials are
cellobiose, citrate, pyridoxal-5- phosphate,
trehalose and sucrose.

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 Immobilization of drug:

The surface modified nano crystalline core
provide the solid phase for subsequent non
denaturing self assembly for a broad range of
biological active molecule.

Drug can be lo

aded by partial adsorption.

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 Characterization of ceramic core:

1. Size distribution-

 For morphological characterization and size
distribution analysis, scanning electron
microscopy (SEM) and transmission electron
microscopy (TEM) are generally used.

 Core, coated core,as well as drug-loaded
aquasomes are analyzed by these techniques.

 Mean particle size and zeta potential of the
particles can also be determined by using
photon correlation spectroscopy.

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2.Structural analysis:

 FT-IR spectroscopy can be used for structural
analysis.

 Using the potassium bromide sample disk
method, the core as well as the coated core
can be analyzed by recording their IR spectra in
the wave number range 4000–400 cm–1;the
characteristic peaks observed are then
matched with reference peaks.

 Identification of sugar and drug loaded over the
ceramic core can also be confirmed by FT-IR
analysis of the sample.

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3. Crystallinity:

 The prepared ceramic core can be analyzed
for its crystalline or amorphous behavior using X-
ray diffraction.

 In this technique, the X-ray diffraction pattern
of the sample is compared with the standard
diffractogram, based on which the
interpretations are made.

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 CHARACTERIZATION OF COATED CORE:

1. Carbohydrate coating

For coating of sugar over ceramic core
Concanavalin A-induced aggregation method
or anthrone method is used. By the help of zeta

potential measurement, absorption of sugar
over the core is recorded.

2. Glass transition temperature

The transition from glass to rubber state as a

change in temperature upon melting of glass

DSC analyser can be used to analyse.

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 CHARACTERIZATION OF DRUG –LOADED
AQUASOMES:

1. Drug payload: It is determined by measuring the
drug in the supernatant liquid after loading which
can be estimated by analysis method.

2. In vitro drug release studies: In this the release
pattern of drug from then aquasomes is
determined by incubating a known quantity of
drug loaded aquasomes in ph at 370C with
continuous stirring. The sample are withdrawn and
centrifuge at high speed for certain length of time
which is later on analysed.

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 APPLICATIONS OF AQUASOMES:

 Aquasomes has got a quite versatile application
potential as a carrier for delivery of vaccine,
haemoglobin,drugs,dyes,enzymes.

1.Aquasomes used as vaccine for delivery of viral
antigen.

2.Aquasomes as red blood cell substitues can
effectively deliver the large,complex labile
molecule,haemoglobin. By incorporating in
aquasome carriers,the toxicity of haemoglobin is
reduced,biological activity is preserved
,haemoglobin concentration of 80% can be
achieved.

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3. Aquasomes for pharmaceutical delivery i.e
insulin developed because drug activity is
conformationally specific. Bioactivity preserved
and activity increased to 60% as compared to iv
administration and toxicity not reported.

4.Aquasomes are used for oral delivery of acid
labile enzyme,serratiopeptidase.enzyme loaded
quasome was further protected by encapsulating
in alginate gel. They protect structural integrity of
enzyme.

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Thank You

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