Aquasomes, principle,methods,

aquasomes

1. AQUASOMES PRESENTED BY C.HARISH (1 st m- pharm )

2. DEFINITION 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 adsorbed with or without modification.

3. AQUASOMES Aquasomes are first discovered by Nir Kossovsky . Aquasomes consists of solid crystalline core, carbohydrate core &active drug Aquasomes are spherical 60-300 nm

4. Aquasomes are also called as “bodies of water” andtheir water like properties protect and preserve fragile biological molecules , This property of maintaining conformational integrity as well as high degree of surfaexposure made it as a successful carrier system for bioactive molecules like peptide, protein, hormones, antigens and genes to specific sites, that is for targeting .

5. METHODS 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.

6. PRINCIPLE OF SELF ASSEMBLY In aqueous biological environments , the assembly of macro molecule Is governed by three process. ( 1) Interaction between charged group. ( 2) Hydrogen bonding and dehydration ( 3) structural stability.

7. 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 . Charged groups also play role in stabilizing tertiary structure of folded proteins . Example of ion pairs - carboxylated /phosphate group boundto ionized arginine / lysine side chain of protein.

8. 2)HYDROGEN BONDING AND DEHYDRATION EFFECT 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 . Molecule that form hydrogen bonds are hydrophilicand these molecules confer significant degree of organization to the surrounding water molecules.

9. 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 vanderwalls interaction among hydrophilic side chains promotes stability of compact helical structures.

10. METHODS OF PREPARATION By using the principle of self assembly Aquasomescan be prepared by three method. 1.Preparation of core. 2. coating of core. 3. Immobilization of drug molecule.

11. 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 ,as they are structurally to be known..

12. 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.

13. 3 inch diameter target of highly purified Tin is sputtered ↓ High pressure gas mixture of argon and oxygen. ↓ The ultra fine particle form in gas phase are collect on copper tube and cool at 70oK with liquid nitrogen

14. SYNTHESIS OF NANA CRYSTALBRUSHITE (CALCIUMPHOSPHATE DIHYRATE) 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

15. 2)CARBOHYDRATE COATING The second step involves coating by carbohydrate on the surface of ceramic cores . There are number of processes to enable the carbohydrate ( polyhydroxy oligomers ) coating to adsorb epitaxially on to the surface of the Nano crystalline ceramic cores.

16. Process generally entail Addition of poly hydroxy oligomer ↓ To a dispersion of core in ultra pure water . ↓ Lyophilization (to promote the adsorption of carbohydrate on the surface of ceramic core ) ↓ Excess of carbohydrate is removed by stir cell ultra filteration .

17. Commonly used coating material, - Cellobiose - Citrate - Sucrose - Trihalose - Pyridoxal -5- phosphate. ( 3) Immobilization of drug The surface modified Nano crystalline core provide the solidphase for subsequent non denaturing self assembly for a broad range of biological active molecule. Drug can be loaded by partial adsorption