full issue - Association of Biotechnology and Pharmacy
full issue - Association of Biotechnology and Pharmacy
full issue - Association of Biotechnology and Pharmacy
- No tags were found...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
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)973to liposomes produced in the presence <strong>of</strong> ethanolcomprise <strong>of</strong> hydroalcoholic or hydro/alcoholic/glycolic phospholipids with high concentration <strong>of</strong>alcohol may be upto 50 % (2, 6, 12, 13, 14).The ethosomal system consists <strong>of</strong>phospholipids, ethanol <strong>and</strong> water (15) Thephospholipids with various chemical structureincludes phosphatidylcoholine (PC), hydrogenatedPC, phosphatidylethanolamine (PE), phosphatidylglycerol (PPG), phosphatidylinositol (PI),hydrogenated PC etc (16). The nonaqueous phaserange between 22 % to 70 %. The alcohol maybe ethanol or isopropyl alcohol. Dyes oramphiphilic fluorescent probe such as D – 289,Rhodamine – 123 , fluorescence isothiocynate(FITC), 6 – carboxy fluorescence are <strong>of</strong>ten addedto ethosomes for characterization study (3, 17,18).Effect <strong>of</strong> high alcohol concentration: Ethanolis an established permeation enhancer <strong>and</strong> isproposed that it fluidizes the ethosomal lipids <strong>and</strong>stratum corneum bilayer thus allowing the s<strong>of</strong>t,malleable vesicles to penetrate the disorganizedlipid bilayer (8). The relatively high concentration<strong>of</strong> ethanol (20 – 50 %) is the main reason forbetter skin permeation ability <strong>and</strong> is packed lesstightly than conventional vesicles but hasequivalent stability <strong>and</strong> better solubility <strong>of</strong> manydrugs (3,19). Moreover the vesicular nature <strong>of</strong>ethosomal formulation could be modified byvarying the components ratio <strong>and</strong> phospholipids(20). Ethanol confers a surface negative netcharge to the ethosome which causes the size <strong>of</strong>vesicles to decrease. The size <strong>of</strong> ethosomalvesicles increase with decreasing ethanolconcentration (3).Advantages <strong>of</strong> ethosomes1. Enhanced permeation <strong>of</strong> drug molecules to<strong>and</strong> through the skin to the systemiccirculation (3, 14).2. Contrary to deformation liposomes,ethosomes improve skin delivery <strong>of</strong> drugsboth under occlusive <strong>and</strong> non-occlusiveconditions (22).3. Since composition <strong>and</strong> components <strong>of</strong>ethosomes are safe, they have variousapplications in pharmaceutical, veterinary<strong>and</strong> cosmetic field.4. Better patient compliance.5. Better stability <strong>and</strong> solubility <strong>of</strong> many drugsas compared to conventional vesicles.7. Relatively smaller size as compared toconventional vesicles.Limitations <strong>of</strong> ethosomes1. Poor yield (23).2. In case if shell locking is ineffective thenthe ethosomes may coalescence <strong>and</strong> fallapart on transfer into water.3. Loss <strong>of</strong> product during transfer form organicto water media (24)Methods <strong>of</strong> preparation ethosomes: Ethosomescan be prepared by two very simple <strong>and</strong> convenientmethods that is hot method (Fig 1 <strong>and</strong> Fig 2) <strong>and</strong>cold method (Fig 3) (16, 17, 18, 25)Fig.1. General method for the preparation <strong>of</strong> ethosomesAbdul Wahid et al