Nanoemulsions –as a Novel drug delivery system

Presented by-Anup Kumar

Dept. of Medical devices(NIPERA1618MD01)

INTRODUCTION Nanoemulsions may be defined as the novel

drug delivery system which is thermodynamically stable, isotropic in nature where two immiscible liquid i.e a water system & a oil system are mixed together to form a single phase by means of an apporopriate surfactant.In nanoemulsion the oil droplets containing the hydrophobic drug that has to be delivered to a targeted organ and the mean droplet diameter ranging 50-500 nm.

Basic structural view of Nanoemulsion system

Advantages of Nanoemulsions Nanoemulsions increase the rate of drug absorption. The very small droplet size causes a large reduction in the

gravity force and the brownian motion is sufficient for overcoming gravity .This mean that no creaming or sedimentation occurs on storage.

It helps to solubilize lipophilic drugs. Various routes like topical,oral,I.V. etc. can be used to deliver

the product. It improves the bioavailability of drugs. It can be formulated in varity of formulation such as foams,

liquids,sprays &creams. It may be used as a substitute for liposomes. It is thermodynamically stable. Possibilities of controlled drug release & drug targeting.

Limitations of NanoemulsionsThe formulation of nanoemulsions is an

expensive process due to size reduction of droplets is very difficult as it required special kind of instruments & prrocess methods.For example homogenizer arrengement is an expensive process.

Oswald ripening could damage the nanoemulsions.

Changing of pH may cause stability problems.

Difference between Emulsions &NanoemulsionsEMULSIONS NANOEMULSIONS1. Anisotropic2. Appearance is cloudy3. Thermodynamically

unstable.4. Wet gum method,Dry

gum method are used for preparation.

5. Higher surfactant concentration(20-25%)

6. Creaming ,sedimentation &phase inversion etc stability problem may occur.

1. Isotropic2. Appearance is

transparent.3. Thermodynamically stable4. Microfludization,ultraso

und generators etc. technique are used for preparation.

5. Lower surfactant concentration(5-10%)

6. These type of problems not occur.

Formulation of NanoemulsionsOil phase- Captex,isopropyl myristate,castor oil etc.Surfactants-potassium & sodium

stearate,isopropanol amine,N-dodecyl alanine,cetrimide,benzalkonium chloride,tween 20,macrogol esters etc.

Co-surfactants-Ethanol,propanol,propylene glycol etc.

AntioxidantsTonicity modifierspH adjusting agentsPreservatives

Preparation of NanoemulsionsHigh-energy emulsification method- This

emulsification method involve high mechanical energy.There are several devices like the rotor/stator,sonifiers

or ultrasound generator ,high pressure homogenizers etc.used to force the creation of huge interfacial areas.

Low-energy emulsification method-Require low mechanical energy for fabrication of emulsions.Subsequent emulsification & phase inversion technique are used.

Preparation of homogeneous organic solution>organic phase added in the aqueous phase >removal of water miscible solvent by evaporator.

Micro fluidizationThis device uses a high pressure positive displacement pump(500-20000psi),which forces the coarse emulsion through the interaction chamber which consist of a small channels called Micro-channels.The product flows through the Micro-channels which resulting in very fine particles of nano range.

Preparation of Nanoemulsion

Characterization of NanoemulsionPreliminary characterizationMorphology and structure Invitro skin permeation studyDroplet size analysisRefractive indexSurface charge(zeta potential)Viscosity

ViscosityIncreasing the water content lowers the viscosity of nanoemulsion while decrease the amount of surfactant or co-surfactant increase the interfacial tension between water and oil resulting in increase viscosity.

Droplet size Analysis

It is done by using helium-neon laser having a particular wavelength of 632.8 nm.

Surface chargeIt is determined by the using of Zetasizer Nano Z . Zeta potential characterizes the surface charge of particles. Thus it gives information about repulsive forces between particles and droplets.To obtain stable nanoemulsion zeta potential should have a value about 30mV.

Refractive indexThe refractive index of nanoemulsion formulation is determined by using abbe type refractometer. It gives the information about isotropic nature of nanoemulsion system.

Applications of Nanoemulsion in drug delivery systemParenteral drug deliveryOcular drug deliveryPulmonary drug deliveryTransdermal or Topical drug delivery Intranasal drug deliveryTumor targeted drug delivery for cancer

therapyOral drug delivery

Parenteral drug deliveryBoth o/w & w/o nanoemulsions system can be

used.Generally I.V route is preferred.Nanoemulsion is cleared more slowly than the

coarse particle emulsion and therefore have a longer residense time in body.

Frequency of dosage of injection can be reduced throughout the drug therapy.

Parenteral nanoemulsion formulation of the following drugs have been documented- carbamazepine,diazepam,dexamethasone etc.

Intranasal Drug deliveryUsed as a vehicle system for brain targeted

drug delivery.Nanoemulsions loaded with drugs like

risperidone ,rizatriptan etc. are very useful in the treatment of CNS disorders like parkinson’s,migraine,meningitis etc.

Ocular drug deliveryNanoemulsions increase the contact time

of the drug in the eye.High ability of drug penetration into the

deeper layers of the ocular structure & aqueous humor.

Reduce the need for frequent administration.Nanoemulsions of dorzolamide.Hcl shows

high therapeutic efficacy & prolonged effect.

Tumor targeted drug deliveryAct as a vehicles for targeted drug delivery of

various aqueous insoluble anti cancer drugs,photosensitizers,diagnostic agents for cancer therapy.

Devolpement of magnetic nanoemulsion is an innovative approach for cancer therapy.These can be deliver photosensitizers like Foscan to deep tissue layers across the skin thereby inducing hyperthermia.

Pulmonary drug deliveryTo achieve relatively uniform distribution

of drug dose among the alveoli.Able to transfect pulmonary epithelial cells.A novel pressurized aerosol system for the

pulmonary delivery of sulbutamol.

Oral drug deliveryNanoemulsions was devoloped to increase

oral bioavailability of hydrophobic drugs.GIT distrubances can be avoided.High concentration of paclitaxal was

observed in the systemic circulation when it is formulated in nanoemulsion form.

Transdermal drug deliveryNano sized emulsions are able to easily

penetrate the pores of the skin and reach the systemic circulation.Thus getting channelized for effective drug delivery.

Able to controlled the locally applied drug redistribution through cuteneous blood & lymph vessle system.

w/o nanoemulsions of caffeine , indomethacin ,aceclofenac etc. have been developed for transdermal drug delivery.

Others Applications…Antimicrobial NanoemulsionsCell culture TechnologyVaccines delivery

Future Perspective…Future perspectives of nanoemulsions are

very promising in different fields of drug delivery for more efficacy , applications in development of cosmetics for skin.

May be become ideal drug delivery platform for the phyto pharmaceuticals.

Conclusion… Nanoemulsions offers several advantages

as well as applications for novel drug delivery and thus receiving increasing attention as drug carriers for improving the delivery of active pharmaceutical ingredients.

They can applicable for almost all routes of drug delivery and therefore hold the promises for different pharmaceutical field.This new approach could be devoloped to overcome the problem associated with the treatment of AIDS, genetical disorders and its own stability problems etc.