Current Trends in <strong>Biotechnology</strong> <strong>and</strong> <strong>Pharmacy</strong>Vol. 5 (1) 972-981 January 2011. ISSN 0973-8916 (Print), 2230-7303 (Online)9759. Phospholipid – ethanol interaction:Phospholipid – ethanol interaction can be assessedby 31 P NMR or by differential scanningcalorimeter (DSC) (20).10. Drug content: Drug content <strong>of</strong> ethosomalformulation can be quantified by a modified highperformance liquid chromatographic technique(HPLC) (27).11. Stability study: Dynamic light scatteringmethod or transmission electron microscope canbe used for assessing the stability <strong>of</strong> ethosomes(33).12. Penetration <strong>and</strong> permeation studies:Depth <strong>of</strong> skin penetration from ethosome can bedetermined by confocal laser scanning microscope(CLSM) (34).13. In vitro skin permeation/ depositionstudy: The in vitro permeation characteristic <strong>of</strong>ethosomal formulation can be done by using franzdiffusion cell with artificial or dialysis bag diffusionor biological membranes such as heat separatedhuman epidermis, human epidermis, male nudemouse abdominal skin, rat abdominal skin, rabbitpinna skin, dermatomed cadaver human skin <strong>and</strong>rat skin (14,29,35,36,37).Mode <strong>of</strong> action <strong>of</strong> ethosomesThe lipid multilayer, at physiologicaltemperature is densely packed <strong>and</strong> highlyconformational order <strong>and</strong> hence main barrier forpermeation <strong>of</strong> drugs (38). The enhanced delivery<strong>of</strong> drugs using ethosomes can be due to interactionbetween ethosomes <strong>and</strong> skin lipids. The possiblemechanism <strong>of</strong> interaction is due to “ethanoleffect” <strong>and</strong> “ethosome effect” (39). Ethanolincreases the fluidity <strong>and</strong> decreases the density<strong>of</strong> lipid molecules by interacting with lipidmolecules in the polar head group region whichin turn result in increased permeability.Fig.4. Mode <strong>of</strong> action <strong>of</strong> ethosomesEthosomes effect include penetration <strong>of</strong> flexibleethosome vesicle through disturbed stratumbilayers <strong>and</strong> opening <strong>of</strong> new pathways due to themalleability <strong>and</strong> fusion <strong>of</strong> ethosomes with skinlipids, resulting in the release <strong>of</strong> the drug in deeplayers <strong>of</strong> the skin (3,16,20,22,40).Application (Table 1)1. Pilosebaceous targeting: Pilosebaceous unitshave been use for localized therapy,particularly for the treatment <strong>of</strong> follicle relateddisorders such as acne or alopecia. Ethosomalformulation <strong>of</strong> minoxidil a lipid soluble drug usedfor baldness accumulate into nude mice skin twoto seven fold higher <strong>and</strong> thus can be use forpilosebaceous targeting for better clinical efficacy(2,20).2. Transdermal delivery: Since ethosomesenhance permeability <strong>of</strong> drug through stratumcorneum barrier, it can be use for administration<strong>of</strong> drugs having poor skin permeation, low oralbioavability, first pass metabolism <strong>and</strong> doseMahdipour et al
Current Trends in <strong>Biotechnology</strong> <strong>and</strong> <strong>Pharmacy</strong>Vol. 5 (1) 972-981 January 2011. ISSN 0973-8916 (Print), 2230-7303 (Online)976Table 1 : Applications <strong>of</strong> ethosomesDrugsAnti- viral agents(Zidovudine)(41)(Lamivudine)(27)(Stavudine) (42)NSAIDS (17,18)(Dicl<strong>of</strong>enac)(Acecl<strong>of</strong>enac)(43)Acyclovir (4)Topical ( 44)PhotodynamicTherapy (PDT)(5- aminolevulinic acid)Insulin (14,45)TrihexyphenidylHydrochloride(14)Antibiotic (46)(Erythromycin)(Cannabidol)Pilosebaceous (2)Targeting(Minoxidil)Ammonium (29)glycrrhizinateSalbutamol sulfate (47)ResultProlonged drug action, reduced drug toxicity.Control release for prolonged period <strong>of</strong> time.Improved biological anti-inflammatory activity, sustained effect.Selective <strong>and</strong> prolong delivery <strong>of</strong> drug to desired site.Superior to the marketed gel for the topical administration.Increased skin permeation <strong>and</strong> biological activity two to three times.Greater penetration ability than that <strong>of</strong> liposomes, More entrapment efficiencySignificant decrease in blood glucose level.Higher entrapment capacity, improved tansdermal flux, improvedpatient compliance.Complete inhibition <strong>of</strong> infection, prolonged drug action.Improved skin deposition <strong>and</strong> biological activity.High penetration into deep layers <strong>of</strong> the skin.Improved biological anti-inflammatory activity, sustained effect.Controlled release rate, enhanced skin permeation.Propranolol (35) Better skin permeation.Testosterone (48) Significantly higher permeation into the skin increased systemically delivery.Finasteride (49) Enhanced percutaneous absorption.Bacitracin (50) Reduced drug toxicity.Methotrexate (51) Enhanced transdermal flux, lower lag time, higher entrapment efficiency <strong>and</strong>(MTX)better stability pr<strong>of</strong>ileGold Nanopartical Gold nanopartical in ethosomes shows enhancement <strong>of</strong> pharmacological(52) efficacy in transdermal <strong>and</strong> dermal delivery systems.Ethosomes: A Tool for Transdermal Drug Delivery