WHAT ARE AQUASOMES.pdf

Aquasomes
Prepared By: Pawan Dhamala
RR College of Pharmacy

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NOTES ON AQUASOMES

 WHAT ARE AQUASOMES??

1. Aquasomes were first discovered by Nir Kossovsky.
2. These are nanoparticulate carrier systems with three layered self-assembled structures.
3. These comprises of central solid nanocrystalline core coated with polyhydroxy
oligomers onto which biochemically active molecules are adsorbed.
4. Aquasomes are spherical in shape and 60-300nm in diameter.


 PROPERTIES
1. Aquasomes due to their size and structure stability, avoid clearance by
reticuloendothelial system or degradation by other environmental challenges
2. Aquasomes possess large size and active surface hence can be efficiently loaded with
substantial amounts of agents through ionic, non-covalent bonds, van der waals forces
and entropic forces.
3. As solid particles dispersed in aqueous environment, they exhibit physical properties
of colloids
4. Aquasomes are also called as “bodies of water” and their water like properties protect
and preserve fragile biological molecules,This property of maintaining conformational
integrity as well as high degree of surface exposure made it as a successful carrier
system for bioactive molecules like peptide, protein, hormones, antigens and genes to
specific sites, that is for targeting.

 METHOD OF PREPARATION OF AQUASOMES:
By using the principle of self-assembly, the aquasomes are prepared in three steps i.e.,
1. preparation of core,
2. coating of core, and
3. immobilization of drug molecule.

 PRINCIPLE OF SELF ASSEMBLY

In aqueous biological environments, the assembly of macro molecule Is governed by
three

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NOTES ON AQUASOMES

process.
1) Interaction between charged group
 Most of the Biological product are charged due to intrinsic chemical group or absorbed
ion from the biological environment.
 Interaction of charged group such as amino, carbonyl, sulphate, phosphate groups
facilitate the long-range approach of self-assembling sub units.

2) Hydrogen bonding
 Hydrogen bond are formed between hydrogen atom attached to an
electronegative donor atom (Ex oxygen, Nitrogen,) and an electronegative
or basic acceptor (Ex: carbonyl oxygen).
 Hydrogen bond help in base pair matching and stabilization of Secondary
protein structure.

3) Structural stability.
 The structural stability of Protein in the biological environment is
determined by the interaction between charged groups and hydrogen bond
largely external to the molecule and vander walls forces largely internal to
the molecule.
 Vander walls forces are largely responsible for the hardness or softness of
the molecule. The vander walls interaction among hydrophilic side chains
promotes stability of compact helical structures.
 PREPARATION

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NOTES ON AQUASOMES

1) PREPARATION OF CORE:
 This stage mainly depends on the selection of material for core. -its physical
chemical properties.
 This can be fabricated by the -Sonication -Colloidal precipitation.
 For the core material material ceramic material widely used
 Commonly used ceramic core are tin oxide, and calcium phosphate.
 Example: synthesis of nanocrystalline tin oxide core material.
 This can be prepared by -Direct current reactive. Magnetron sputtering. Synthesis
of nano crystalbrushite (calciumphosphate dihydrate)
 This can be prepared by - colloidal dispersion –
 Sonication -By reaction of disodium hydrogen phosphate and calcium phosphate.
 The commonly feature include -Crystalline -They measure b/w 50-150nm. And
exhibit clean and reactive surface.

2) CARBOHYDRATE COATING:




3) 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 loaded by partial adsorption

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EVALUATION OF Aquasomes.
A. CHARACTERIZATION OF COATED CORE
Coating of sugar over the ceramic core can be confirmed by
i. concanavalin A-induced aggregation method (determines the amount of sugar
coated over core) or
ii. anthrone method (Determines the residual sugar unbound or residual sugar
remaining after coating). I
iii. Furthermore, the adsorption of sugar over the core can also be confirmed by
measurement of zeta potential


B. CHARACTERIZATION OF DRUG -LOADED AQUASOMES

 Drug payload
The drug loading can be determined by measuring the drug remaining in the
supernatant liquid after loading which can be estimated by any suitable method of
analysis In vitro drug release studies

 The in vitro release kinetics of the loaded

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drug is determined to study the release pattern of drug from the aquasomes by
incubating a known quantity of drug-loaded aquasomes in a buffer of suitable pH at 37
°C with continuous stirring. Samples are withdrawn periodically and centrifuged at high
speed for certain lengths of time. Equal volumes of medium must be replaced after each
withdrawal. The supernatants are then analyzed for the amount of drug released by any
suitable method .

C. 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; 2. 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.
 Crystallinity: The prepared ceramic core can be analyzed for its crystalline or
amorphous behavior using

Application
 Aquasomes have got a quite versatile application as potential carriers for the
delivery of vaccines, hemoglobin, drugs, dyes, enzymes, peptide, protein,
hormones,
1. Aquasomes are used as vaccines for delivery of viral antigen
2. Aquasomes as red blood cell substitutes 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 and is reported to deliver
oxygen in a non linear manner like natural red blood cells
3. Aquasomes for pharmaceuticals delivery i.e. insulin, developed because drug
activity is conformationally specific. Bio activity preserved and activity
increased to 60% as compared to i.v. administration and toxicity not reported .
4. Aquasomes are used for oral delivery of acid labile enzyme, serratiopeptidase.
Enzyme loaded aquasome was further protected by encapsulating in alginate

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gel. They protect the structural integrity of enzymes and better therapeutic
efficacy was observed .
5. Serratiopeptidase is a proteolytic enzyme obtained from the silkworm. It is used
to reduce pain and swelling associated with conditions like back pain, arthritis,
tension headaches and migraine headaches.