full issue - Association of Biotechnology and Pharmacy

Current Trends in Biotechnology and PharmacyVol. 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 of 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 of ethosomes(33).12. Penetration and permeation studies:Depth of skin penetration from ethosome can bedetermined by confocal laser scanning microscope(CLSM) (34).13. In vitro skin permeation/ depositionstudy: The in vitro permeation characteristic ofethosomal 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 andrat skin (14,29,35,36,37).Mode of action of ethosomesThe lipid multilayer, at physiologicaltemperature is densely packed and highlyconformational order and hence main barrier forpermeation of drugs (38). The enhanced deliveryof drugs using ethosomes can be due to interactionbetween ethosomes and skin lipids. The possiblemechanism of interaction is due to “ethanoleffect” and “ethosome effect” (39). Ethanolincreases the fluidity and decreases the densityof lipid molecules by interacting with lipidmolecules in the polar head group region whichin turn result in increased permeability.Fig.4. Mode of action of ethosomesEthosomes effect include penetration of flexibleethosome vesicle through disturbed stratumbilayers and opening of new pathways due to themalleability and fusion of ethosomes with skinlipids, resulting in the release of the drug in deeplayers of the skin (3,16,20,22,40).Application (Table 1)1. Pilosebaceous targeting: Pilosebaceous unitshave been use for localized therapy,particularly for the treatment of follicle relateddisorders such as acne or alopecia. Ethosomalformulation of minoxidil a lipid soluble drug usedfor baldness accumulate into nude mice skin twoto seven fold higher and thus can be use forpilosebaceous targeting for better clinical efficacy(2,20).2. Transdermal delivery: Since ethosomesenhance permeability of drug through stratumcorneum barrier, it can be use for administrationof drugs having poor skin permeation, low oralbioavability, first pass metabolism and doseMahdipour et al