Nanotechnology Uses in Medical Field

Introduction of Nanoparticles 

The introduction of nanotechnology in medicine is the pharmaceutical approach to formulating drugs as nanoparticles for diagnostic and curing diseases in a targeted drug delivery system.  Nanotechnology is considered to be at a size below 0.1 m or 100 nm (a nanometer is one billionth of a meter).

Nanoparticles are potential drugs which in low amount produces rapid onset of action by enhancing solubility through an increased rate of dissolution. Based on the uptake of murine macrophages nanoparticles has an optimal size range of 10-250nm and surface range between   -10mv and +10mv.Nanotechnology in medicine emerged as two branches, Nanodevices, and Nanomaterials where Nanodevices act by respirocytes.


Nanomaterials classified as polymers and non-polymers [1].Polymers are nothing but the carriers which carries the medicine to the targeted site further which releases drug by a slower disintegration of itself. Due to this specific drug delivery system nanomedicines have gained much interest in the field of cancer, angiogenesis, diabetes, inflammation and Nasal vaccine delivery.

TYPES OF NANOPARTICLES

Nanoparticles are classified into three areas:

1.One dimensional (eg: optical fiber optical system),
2.Two dimensional (Carbon nanotubes)
3.Three dimensional (Dendrimers, Quantum dots, Fullerenes).These can be characterized by SEM and TEM analysis.

FORMULATION OF NANOPARTICLES:[1,2]

SOLVENT EVAPORATION

Emulsification of polymer solution into an aqueous phase and evaporation of polymer solvent by inducing polymer precipitation as nanospheres.A biopolymer is used.

SOLVENT DIFFUSION

A water-miscible solvent in a small amount of organic solvent is used in an oil phase., a turbulence generated will form smaller particles which can be separated by increasing the water-miscible phase.

DOUBLE EMULSION AND DIFFUSION

Addition of aqueous drug solution to organic polymer solution to form w/o emulsion emulsion.which is further exposed to an aqueous solution to form w/o/w emulsion.then solvent removal can be done by evaporation.

SALTING OUT METHOD

Separation of water-miscible solvent from aqueous solution by salting out effect.

The synthetic polymer is used.

PRECIPITATION METHOD

A preformed polymer is precipitated in an organic solvent and organic solution is diffused in an aqueous medium.
 
IONIC GELATION METHOD
 
Electrostatic interaction between the positively charged amino group of chitosan and negatively charged tripolyphosphate to form coacervate size in nanometer.

POLYMERIZATION METHOD 
 
It is the polymerization of monomers in aqueous solution.

SUPERCRITICAL FLUID TECHNOLOGY
 
To prepare biodegradable nanoparticles by avoiding usage of organic solvents.
  

The Two-Step Process of The Production of Drug Nanocrystal Loaded Compounds

Fig.1.The drug nanosuspension is obtained by high-pressure homogenization (Micron Lab 40) is further processed by spray drying using a Mini Bu¨ chi. Drug nanocrystals embedded in the matrix are obtained. 

Fig.2.Modelling of Microparticles

PEG, Polyethylene Glycol

Fig.3. Capsules filled with granulated PEG 2000 containing Amphotericin-B nanocrystals (left), tablets produced by compaction of the granulate (right). Abbreviation: PEG, Polyethylene Glycol.

SEM Photograph of Nanocrystals 

Fig.4. SEM photograph: left—uncoated matrix core containing drug nanocrystals (magnification 60), right top—detail magnification (1000) of this matrix core with drug nanocrystals (arrow), right bottom—detail magnification (1000) of matrix core without drug nanocrystals. Abbreviation: SEM, scanning electron microscopy.

ROLE OF POLYMERS IN NANOTECHNOLOGY [3]
 
The role of polymers in nanomedicine is very targeting every day.This is why the reason for the development of nanotechnology in medicine.Polymers are classified as:


Natural Polymers: Polysaccharides,Starch,Chitosan,gelatin,albumin.

Synthetic Polymers: Polycaprolactone (PCL), Polylactic acid (PLA).Polyalkylacrylate.

Polymeric Nanoparticles: Modification of natural polymers.eg. poly (D,L lactide), Polycyanoacrylate,poly(lactide-co-glycolide). It is comprised of the vesicular system (nanocapsules: drug is confined to a cavity surrounded by a polymeric membrane.), matrix system(nanospheres: drug is dispersed throughout the polymeric matrix). These are non-toxic and non-immunogenic in nature.

Multifunctional polymeric nanoparticles: Environmental responsive micelles, colloids,nano-hydrogel,core-shell nanoparticles. 

·         Unique Class of Polymers

Dendrimers: hyperbranched and have compartmentalized chemical polymer.

Micelles: Amphiphilic block of copolymers. 
 
Drug conjugates: Formed by conjugation of low molecular weight drug with a polymer.

SYNTHESIS OF BIOCOMPATIBLE POLYMERS

• Electrodropping system
• Microfluidic system
• Core-shell particulate system
• Sonication based system

Advanced Techniques of Preparation of Polymeric Nanoparticles

Fig.5.Schematic diagrams representing the advanced techniques of preparation of polymeric nanoparticles

TARGETED DRUG DELIVERY SYSTEM[1,2]

This system delivers drug at a constant rate from the membrane.The mechanism of action is drug in nanoformulation is surrounded by a preprogrammed polymeric membrane.The drug will be released at the target site at a constant prefixed rate. Drug release is purely based on molecules, its diffusion properties, partition coefficient, the dimension of the membrane and also crosslinked polymeric network.Changes in the membrane can be formed by either physical, chemical, environmental stimuli.

Fig.6.Targeted Drug Delivery System

APPLICATION OF NANOMEDICINES[4]

The use of nanomedicine is tremendous. Usage of biopolymers result in reduced toxicity and increased specificity which plays a vital role in gene delivery and vaccination.Synthetic nanometer usage leads to treatment in the field of cancer, plaque, musculoskeletal disorders, and kidney diseases. By modifying the route of administration, it helps the drug to cross BBB through nasal route.

By parenteral route using microneedles and jet injection.Through transdermal rout by skin patches, which all eliminates pain.Nanoparticles are used in the oral delivery of peptides and proteins.Nanopores used to protect transplanted tissues from host immune system.

The Niosome ability to load both hydrophilic and lipophilic drugs. Pharmacyte is self-powered computer-controlled medical nanorobot system capable of digitally precise transport timing and target drug delivery.

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4. A.P.Anconabi, m.o.emeje, recent application of natural polymers in nano drug delivery pub 2011 s4.

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