IJPAR |Vol.8 | Issue 1 | Jan – Mar – 2019 Journal Home page: www.ijpar.com
Research article Open Access
A review on nanoparticles
A.Tejaswini
1, Ch.Sylvia
1, P.Vasudha
1, M.Pravallika
1, N.Sai Jeelan
11
Department of Pharmaceutics, P.Rami Reddy Memorial College of Pharmacy, Kadapa, A.P
*Corresponding Author: Tejaswini A Email: [email protected]
ABSTRACT
To improve the pharmacokinetic and pharmacodynamics activity of the drug medication system like nanoparticles has made a break through by means of physical application. By means of targeted drug delivery system the targeted drug delivery will be achieved quickly. To maintain a controlled and sustain the rate of drug exposure on the site of action nanoparticles are used. That’s the reason why the nanotechnology became as the most advanced in the field of medicine by maintaining the therapeutic benefits. The development of effective nanodelivery systems capable of carrying a drug specifically and safely to a desired site of action is one of the most challenging tasks of pharmaceutical formulation investigators. They are attempting to reformulate and add new indications to the existing blockbuster drugs to maintain positive scientific outcomes and therapeutic breakthroughs. The nanodelivery systems mainly include nanoemulsions, lipid or polymeric Nanoparticles and liposomes.
Keywords: Nanoparticle, Nanotechnology, Gene therapy, Targetting, Preparation techniques
INTRODUCTION
Nanotechnology employs knowledge from the fields of physics, chemistry, biology, materials science, health sciences, and engineering. It has immense applications in almost all the fields of science and human life. Nanoparticles are defined as particles between 10-1000nm in size with a surrounding interfacial layer. The drug is either dissolved, entrapped, encapsulated or attached to a nanoparticle matrix. Depending upon the method of preparation nanoparticles, nanospheres or nanocapsules can be obtained. Nanocapsules are
systems in which the drug is confined to a cavity surrounded by a unique polymer membrane, while nanospheres are matrix systems in which the drug is physically and uniformly dispersed [1].
In recent years,biodegradable polymeric nanoparticles, particularly those coated with hydrophilic polymer such as poly(ethylene glycol) (PEG) known as long-circulating particles, have been used as potential drug delivery devices because of their ability to circulate for a prolonged period time target a particular organ, as carriers of DNA in gene therapy, and their ability to deliver proteins, peptides and genes [2,3].
Nanotechnology is the science which deals with small; the very small particles. At the Nano size, atoms and molecules exhibits surprising and interesting outcomes by working differently which results in various scientists to concentrate on these to use in many fields like medical, Pharma, engineering etc. Delivering therapeutic compound to the target site is a noteworthy issue in treatment of many diseases. Many conventional dosage forms failed in vain in delivering the drug at specific site of action due to its limited effectiveness, poor bio-distribution, and lack of selectivity. These limitations and draw backs can be overcome by
novel drug delivery systems Through novel drug delivery systems various drugs can be delivered to the desired (specific) sites showing its pharmacological activity by minimizing side effects. More over novel drug delivery systems protects drug from rapid degradation and maintains drug concentration at specific sites or in target tissues hence lower doses of drug are required [4].
Nanostructures have the ability to cross the cell and tissue barriers as its particle size is very small which makes them widely applicable in biomedical sciences.
Fig.1 Types of Nanoparticles
The major goals in designing nanoparticles as a delivery system are to control particle size, surface properties and release of pharmacologically active agents in order to achieve the site-specific action of the drug at the therapeutically optimal rate and dose regimen.
Recent developments in nanotechnology have shown that nanoparticles (structures smaller than 100 nm in at least one dimension) have a great potential as drug carriers. Due to their small sizes, the nanostructures exhibit unique physicochemical and biological properties (e.g., an enhanced reactive area as well as an ability to cross cell and tissue barriers) that make them a favorable material for biomedical applications [5].
ADVANTAGES
The Novel drug delivery system (Nanoparticles) is used to deliver drugs through oral, nasal, parenteral, intra-ocular etc.
Through nanoparticles particle size can be easily altered resulting in attaining both active and passive drug targeting after parenteral administration became the most advantageous in the treatmentent of many chronic diseases.
doses of drug shows high therapeutic efficacy and reduced side-effects.
In the tiny areas of body nanoparticles shows better drug delivery as compare to other dosage form and target to a particular cell type or receptor.
Due to small particle size nanoparticles overcome resistance by physiological barriers in the body and easily penetrates to cell walls, blood vessels, stomach epithelium and blood–brain barrier.
Nanoparticle enhance the aqueous solubility of poorly soluble drug, which improves bioavailability of drug.
As a targeted drug carrier nanoparticles reduce drug toxicity and enhance efficient drug distribution.
By using polymers drug release form nanoparticles can be modified which makes polymeric nanoparticle an ideal drug delivery system for cancer therapy, vaccines, contraceptives and antibiotics.
Useful to diagnose various diseases
Enhanced stability of ingredients
Prolonged shelf life
Used in dental surgery also as filling the tiny holes in teeth.
Change the method of drug delivery to improve customer acceptance or reduce manufacturing costs [6].
APPLICATIONS
Used in targeted drug delivery (therapy) to brain and cancer therapy.
Drug and gene delivery Bio detection of pathogens Detection of proteins Biomarker mapping Probing of DNA structure Tissue engineering
Destruction of tumours through heating process (hyperthermia)
Separation and purification of biological molecules and cells
MRI contrast enhancement Phagokinetic studies [7]
NANOPARTICLE PREPARATION
Nanoparticles are aimed to be prepared from a
variety of materials such as
proteins,polysaccharides and syntheticpolymers. The selection criteria of matrix materials depends on many factors such as
Size of nanoparticles required
Inherent properties of the drug, e.g., aqueous solubility and stability
Surface characteristics such as Charge and Permeability
Degree of biodegradability, biocompatibility and toxicity
Drug release profile desired; and
Antigenicity of the final product.
Nanoparticles preparation is most frequently
by three methods
Dispersion of preformed polymers
a) Solvent evaporation method b) Solvent diffusion method
1. Polymerization of monomers; and
2. Ionic gelation or coacervation of hydrophilic polymers.
3. Salting out 4. Dialysis [8]
DISPERSION
OF
PREFORMED
POLYMERS
Dispersion of preformed polymers is a common technique used to prepare biodegradable nanoparticles from poly (lactic acid) (PLA); poly (D,L-glycolide),PLG; poly (D, L-lactide-co-glycolide) (PLGA) and poly (cyanoacrylate) (PCA). This technique can be used in various ways as described below [9].
SOLVENT EVAPORATION METHOD
using mechanical stirring, sonication, or micro fluidization (high-pressure homogenization through narrow channels). After formation of emulsion the organic solvent evaporate by increased the temperature and reduced pressure with continuous stirring. Particle size was found to be influenced by
the type and concentrations of stabilizer, homogenizer speed and polymer concentration. In order to produce small particle size, often a high-speed homogenization or ultrasonication may be employed [10].
ss
Fig.2 Representation of the solvent-evaporation technique
SPONTANEOUS
EMULSIFICATION
OR SOLVENT DIFFUSION METHOD
This is a modified version of solvent evaporation method. In this method, the water miscible solvent along with a small amount of the water immiscible organic solvent is used as an oil phase. Due to the spontaneous diffusion of solvents an interfacial turbulence is created between the two phases leading to the formation of small particles.
As the concentration of watermiscible solvent increases, a decrease in the size of particle can be achieved. Both solvent evaporation and solvent diffusion methods can be used for hydrophobic or hydrophilic drugs. In the case of hydrophilic drug, a multiple w/o/w emulsion needs to be formed with the drug dissolved in the internal aqueous phase [11].
.
NANOPRECIPITATION METHOD
This is another method which is widely used for nanoparticle preparation which is also called solvent displacement method. This technique was first described by Fessi at al. 1989. In this method precipitation of polymer and drug obtained from organic solvent and the organic solvent diffused in to the aqueous medium with or without presence of surfactant. Tamizhrasi et al prepared Lumivudine loaded nanoparticles. Firstly drug was dissolved in water, and then cosolvent (acetone used for make inner phase more homogeneous) was added into
this solution. Then another solution of polymer (ethyl cellulose, eudragit) and propylene glycol with chloroform prepared, and this solution was dispersed to the drug solution. This dispersion was slowly added to 10 ml of 70% aqueous ethanol solution. After 5 minutes of mixing, the organic solvents were removed by evaporation at 35° under normal pressure, nanoparticles were separated by using cooling centrifuge (10000 rpm for 20 min), supernatant were removed and nanoparticles washed with water and dried at room temperature in a desicator [12].
Fig.4 Representation of the nanoprecipitation technique
COACERVATION METHOD
By using biodegradable hydrophilic polymers (such as chitosan, gelatin and sodium alginate etc) nanoparticle prepared by Coacervation method. Calvo at al prepared nanoparticles by ionic gelation method which involves two aqueous phases. First phase contain polymer like chitosan, a di-block co-polymer like ethylene oxide or propylene oxide (PEO-PPO). Second phase contain polyanion sodium tripolyphosphate. Between these two phases electrostatic interaction occurs which forms coacervates. In this method, positively charged amino group of chitosan interacts with negative charged tripolyphosphate to form coacervates with a size in the range of nanometer. Coacervates are formed as a result of electrostatic interaction between two aqueous phases, whereas, ionic gelation involves the material undergoing transition from liquid to gel due to ionic interaction conditions at room temperature [13].
SALTING OUT METHOD
Fig.5 Representation of the salting out technique
DIALYSIS
Dialysis is an effective method for preparation of nanparticles. In this method firstly polymer (such as Poly(benzyl-l-glutamate)-b-poly(ethylene oxide), Poly(lactide)-b-poly(ethylene oxide)) and drug dissolved in a organic solvent. This solution added to a dialysis tube and dialysis performed against a non-solvent miscible with the former
miscible. The displacement of the solvent inside the membrane is followed by the progressive aggregation of polymer due to a loss of solubility and the formation of homogeneous suspensions of nanoparticles. Dialysis mechanism for formation of nanoparticle is not fully understood at present. It may be based based on a mechanism similar to that of nanoprecipitation [17].
.
SUPERCRITICAL
FLUID
TECHNOLOGY
Conventional methods such as solvent extraction-evaporation,solvent diffusion and organic phase separation methods require the use of organic solvents which are hazardous tothe environment as well as to physiological systems. Therefore, the supercritical fluid technology has been investigated as an alternative to prepare biodegradable micro- and nanoparticles because supercritical fluids are environmentally safe. A supercritical fluid can be generally defined as a solvent at a temperature above its critical temperature, at which the fluid remains a single phase regardless of pressure 21. Supercritical CO2 (SC CO2) is the most widely used supercritical fluid because of its mild critical conditions (Tc = 31.1 °C, Pc = 73.8 bars), nontoxicity, nonflammability, and low price. The most common processing techniques involving supercritical fluids are supercritical antisolvent (SAS) and rapid expansion of critical solution (RESS). The process
of SAS employs a liquid solvent, eg methanol, which is completely miscible with the supercritical fluid (SC CO2), to dissolve the solute to be micronized; at the process conditions, because the solute is insoluble in the supercritical fluid, the extract of the liquid solvent by supercritical fluid leads to the instantaneous precipitation of the solute, resulting the formation of nanoparticles. RESS differs from the SAS process in that its solute is dissolved in a supercritical fluid (such as supercritical methanol) and then the solution is rapidly expanded through a small nozzle into a region lower pressure, Thus the solvent power of supercritical fluids dramatically decreases and the solute eventually precipitates. This technique is clean because the precipitate is basically solvent free. RESS and its modified process have been used for the product of polymeric nanoparticles. Supercritical fluid technology technique, although environmentally friendly and suitable for mass production, requires specially designed equipment and is more expensive [18-22].
CONCLUSION
Nanotechnology is opening prospective future in pharmaceutics. Nanoparticle is novel approach for drug delivery which we can achieve better therapeutic action, better bioavailability, reduce toxicity. Today nanoparticles are successfully used
in brain targeting, in cancer therapy etc. nanoparticles gives us an opportunity to enhance patient compliance for better therapy. Due to their incredible properties, Nanoparticles have become significant in many fields in recent years such as energy,health care,environment,agriculture etc.
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