Electrical capacitance of lipid bilayer membranes of hydrogenated egg lecithin at the temperature phase transition

Abstract

Electrical capacitance of the planar bilayer lipid membrane (BLM) formed from hydrogenated egg lecithin (HEL) has been studied during many passages through the phase transition temperature. In contrast to the BLM from individual synthetic phospholipids, membranes from HEL did not demonstrate any capacitance change at the phase transition temperature maximum, as measured by differential scanning calorimeter at 52 degrees C. Instead, two temperatures have been discerned by capacitance records: thickening at 42-43 degrees C and thinning at 57-59 degrees C. The first temperature region is close to the transition temperature of dipalmitoyllecithin, whereas the second is close to that of distearoyllecithin, two main components of the HEL. It was suggested that capacitance measurements were able to reveal a phase separation in the BLM from HEL which was not detected by differential scanning calorimetry. The phase transition of the BLM from the liquid crystal state to the gel state is followed by thickening of the bilayer structure, partly due to a gauche- trans transition of lipid molecules but mainly due to redistribution of the solvent n-decane.

The effect of added liposomes on the rheological properties of a hydrogel: A systematic study

“…Thereby, our suggestion for the explanation of these results is that the rigidity of the HPC (and HPC/chol) liposomes is such that they do not behave comparably with the gel in which they are dispersed under stress conditions, resulting in modification of the flow and elastic properties of the complex gel, compared to the control. This is probably also related to the fact that HPC liposome membranes are in the gel state at the temperature used in the study (37 • C), since the transition temperature of HPC is 50 • C [21]. On the other hand, PC liposomes are in the fluid state (the transition temperature of PC is below zero) and under stress conditions they should be more easily deformed, explaining the fact that the rheological properties of the PC-loaded complex gels are determined by the gel itself and only minimally influenced by the liposomes.…”

“…1b and 1d) has a significantly different effect on shear viscosity. This is indeed the case for PC and HPC liposomes, which were studied herein, most probably because these two lipid compositions produce liposomes with completely different membrane rigidity; membranes composed of PC are in the liquid state at room and body temperature, since the transition temperature of PC is lower than room temperature, while HPC membranes are very rigid at these temperatures since the lipid transition temperature is around 50 • C [16,21].…”

Cetirizine from topical phosphatidylcholine-hydrogenated liposomes: Evaluation of peripheral antihistaminic activity and systemic absorption in a rabbit model

“…In recent studies, various medications have been incorporated into liposomes for topical delivery. [7][8][9][10][11]18 Cetirizine, a potent second-generation H 1 -antihistamine, is effective for the treatment of allergic skin disorders but is minimally sedating when given orally. It was hypothesized that by administering cetirizine in liposome formulations to the skin, the peripheral H 1 -antihistaminic activity would be retained, while absorption into the systemic circulation would be reduced, potentially reducing even the minimal sedative adverse effects.…”

“…The transition temperature of L-α-phosphatidylcholine hydrogenated (HPC), 50°C, is much higher than ambient temperatures. 8 Liposomes, as drug delivery systems, have been shown to transport and localize hydrophilic, polar drugs into the skin yielding increased therapeutic effects and reduced systemic adverse effects. [9][10] In addition, application of liposomes moisturizes the skin 11 and reduces the irritation resulting from allergic skin disorders such as urticaria.…”

Prolongation of Anti-Inflammatory Activity of Glucocorticosteroids Encapsulated in Large Oligolamellar Liposomes in Treatment of Arthritis in Rabbits

“…The structure and permeability of liposomes are known to change in the lipid melting phase-transition temperature (T m ) range. (8) This property of lipids is used to increase the rate of drug release from the aqueous phase of the vesicles due to hyperthermia. There are a number of reasons to believe that bringing closer the phase states of the vesicle membrane and the plasma membrane of the target cells, which are synovial cells in this case, may facilitate their interaction.…”