Phospholipids Lab Report

Scheme of a liposome formed by phospholipids in an aqueous solution.

The stable membranes are naturally found to be made up of bi layers of phospholipids. When water is present the head group gets attracted to water and they make up to form a surface which faces the water where as the tail group is repelled by it and they form a surface away from the water. So in a cell we can observe that one layer will have its heads facing outer side of the cell i.e attracted to the environment's water where as the other layer will be facing the inner side of the cell attracted to the water which is in the cell. Both the hydrocarbon layers face each other to give an appearance of bilayer.33

If there is a disruption of the phospholipid membrane then they

Ethosomes are a modified form of liposomes. Ethosomes constitute soft vesicles of lipid containing phospholipids, water and alcohol (isopropyl alcohol and ethanol) in a comparatively higher concentration. They have a size which ranges from tens of nano meters to microns35-37. The permeation of ethosomes via skin layers is more rapid and they possess transdermal flux in a higher range. The delivery of active agents is enhanced by the ethosomes and it chiefly comprises of phospholipids( phosphatidylserine, phosphatidic acid , phosphatidylcholine) water and higher concentration of alcohol. Ethosomes are unique to the presence of higher concentration of ethanol in it whose nature is to disturb the bilayer organisation thus when put in a vesicle ,the vesicle gains the ability to get penetrated into the stratum corneum. Also due to the higher concentration of ethanol the lipid membrane is less tightly packed than the conventional type of vesicles but has the same stability. It allows even structures which are more malleable and thus distribution of the drug is

The different types of phospholipids with varied chemical structure are phosphatidyl choline PC, hydrogenated PC, phosphatidyl ethanol amine PE, phosphatidyl inositol, phosphatidyl glycerol (PPG). The range of non- aqueous phase may be from 22% to 70% and the type of alcohol may be either isopropyl alcohol or ethanol. For characterization studies fluoroscent probes of ampiphilic nature such as Rhodamine-123, D-289, 6-carboxy fluorescence, fluorescence isothiocyanate (FITC) are usually added to the ethosomes.39-40

Mechanism:

Confocal laser scanning microscopy (CLSM) can assess the depth of skin penetration by ethosomal systems. To study the penetration of skin different fluorescent probes of different physico chemical properties like carotene C, Rhodamine red, Rhodamine 6G, Rhodamine B can be enclosed inside the ethosomal vesicles41-42. The temperature for transition of the lipid in the vesicular systems can be known in the form of softness of vesicle and it is influenced by the drug and the concentration of ethanol. The determination of stability storage of ethosomal systems can be done by comparison of the average size, shape, capacity of entrapment by the vesicles at varied conditions of storage. Depending on the different studies conducted on stability researchers have suggested that the suitable storage condition for ethosomes are refrigeration condition which is (4-8)C