Design of intradermally permeable liposomes: Focus on surface properties and lipid composition

Anatomical Variation in the Amount and Composition of Human Skin Surface Lipid

BackgroundNanotechnology for drug delivery to cancer cells is hampered by abundant uptake by myeloid cells, with the majority of nanoparticles ending up in filtering organs.1 Kupffer cells or other resident...

Variation of skin surface lipid composition among mammals

SUMMARY The effect of local change in forehead skin temperature on both surface lipid composition and sebum excretion rate was studied in thirty-six subjects. The sebum excretion rate varied directly with local temperature change so that a change in temperature of 1° C produced a change in the sebum excretion rate of the order of 10%. Significantly less squalene was detected in surface lipid when forehead temperature was decreased but no other temperature dependent variations in the composition of surface lipid were observed.

Surface lipids in lipoproteins interact with proteins and receptors at the surface of cell membranes, mediating lipoprotein-cell signaling and trafficking events. Despite this, little is known about lipoproteins' surface lipid composition and any changes introduced by type-2 diabetes mellitus (T2DM). Herein, we investigate the surface lipid composition in purified VLDL, LDL and HDL populations isolated from patients with poor (PC, HbA1c>8.5%) and good glycemic control (GC, HbA1c<6.5%) using high-performance thin-layer chromatography (HPTLC) and targeted liquid chromatography-mass spectrometry (LC-MRM-MS) approaches, which were complemented with biophysical measurements. Composed largely of free cholesterol (Chol), phosphatidylcholine (PC), and sphingomyelin (SM), the surface of lipoproteins contains minor quantities of phosphatidylethanolamine (PE), phosphatidylinositol (PI), monoglycerides (MG), ceramides (Cer) and glucosyl-ceramides (GlcCer). Our findings show that PE levels are altered in VLDL and LDL in T2DM. Screening of predominant Chol and PC lipids derivatives, cholesterol sulfate (CholS) and oxidized phosphatidylcholines (oxPC), revealed pronounced changes in LDL. At the biophysical level, T2DM impacted VLDL and HDL surface properties but not those of LDL. The distinct behavior of lipoproteins' composition and biophysical parameters in T2DM patients and in response to medication, diet, and physical exercise, may contribute to particle-membrane interactions.

Cuticular lipids of insects—III. The surface lipids of the aquatic and terrestrial life forms of the big stonefly, Pteronarcys californica newport

Two-polymer aqueous-phase systems were used to compare via partitioning the surface properties of strains of the fish pathogen Aeromonas salmonicida which differed in their ability to produce the surface protein array known as the A layer and in their ability to produce smooth lipopolysaccharide. In these two-phase systems, biological particles are known to partition between the phases in a manner related to a variety of surface properties, including hydrophobicity, charge, and lipid composition. Both the presence of the superficial protein layer and the O polysaccharide chains of lipopolysaccharide were shown to play an important role in the partitioning behavior of A. salmonicida cells. The presence of the A layer, which is crucial to the virulence of A. salmonicida, appeared to decrease the surface hydrophilicity of this pathogen and to increase, in a somewhat specific manner, its surface affinity for fatty acid esters of polyethylene glycol. The ability of two-polymer aqueous-phase systems to differentially partition A. salmonicida cells on the basis of differences in surface architecture suggests their general usefulness for the analysis of surface properties important in bacterial virulence and should permit their use in the selection of strains and mutants exhibiting specific surface characteristics.

The aim of the investigation was to elucidate the extent and directions of possible alterations in the process of biosynthesis of surface lipid (SL) molecules in the presence of some toxicants and realize if some SL molecules could be stress markers. The emphasis is made on some water plants, representatives of helophytes. Some plants (contaminant exposed) grown on sewage ponds of Dniepropetrovs'k varnish-dye plant with complex contamination were investigated. Spectral (Fourier transform infrared, FTIR), thermogravimetric (TG) and gas chromatography — mass spectrometry (GC-MS) data were considered. FTIR-spectra of SL of contaminant non-exposed and contaminant exposed plant samples had some differences concerning absorbtion of some characteristic bands; TG and evolutional profiles of water, also carbon dioxide and carbon monoxide evolution had some differences in control and contaminant exposed plants. The results confirm their different molecular-dynamic characteristics, dependent from content and associative abilities. Changes in composition of SL took place under influence of contaminants. The content of fatty acids and hydrocarbons changed in SL of contaminant exposed plants in comparison with control.

Synthesis and Composition of Surface Lipids of Human Skin

When hairless NCN24 mice with atopic dermatitis (AD) were sprayed with a petroleum-containing alkaline salt spring water rich in metaboric acid and sodium bicarbonate, AD symptoms diminished. Reversed-phase HPLC with fluorescence detection (HPLC/FD) and online MS revealed that fatty acid (FA) composition of the skin surface lipids was similar to that in non-AD mice compared with that in AD mice. Strong negative correlations were noted between the levels of total serum immunoglobulin E (IgE) and palmitoleic acid and between the levels of total serum IgE and branched-hexadecanoic acid. Conversely, a strong positive correlation was noted between the levels of total serum IgE and linoleic acid. The present study demonstrates that the petroleum-containing spring water alters the FA composition of skin surface lipids in AD mice, which can be used as an index to evaluate inflammation.

Surface lipid composition in children with protein-calorie malnutrition

We previously discovered that squalene monohydroperoxide (SQ-OOH) was produced on human forehead skin and suggested that skin squalene (SQ) may be the principal target lipid for oxidative stress (e.g., sunlight exposure). Because of its six double bonds, SQ peroxidation can yield various positional hydroperoxide isomers. However, the structural characterization of skin SQ-OOH isomers has never been reported. Here, we prepared pure SQ-OOH isomers and developed an analytical method for SQ-OOH isomers using a quadrupole/linear ion-trap mass spectrometer (QTRAP) MS/MS system. Collision-induced dissociation produced specific fragment ions for each SQ-OOH isomer, which permitted discrimination between SQ-OOH isomers by multiple reaction monitoring (MRM). When lipid extract from human forehead skin was subjected to LC-MS/MS with MRM, individual SQ-OOH isomers could be separated and detected with a sensitivity of 0.05 ng/injection. The total concentration of SQ-OOH isomers in forehead skin was approximately 956 microg/g skin lipids, but it increased up to 2,760 microg/g skin lipids after 3 h of sunlight exposure. The LC-MS/MS method was useful for investigating the peroxidation mechanisms of SQ as well as SQ-OOH-mediated skin disorders.

Lipid based vesicular drug delivery system, one of the emerging technologies designed for addressing the delivery challenges of conventional drug delivery methods, has widespread applications in chemotherapeutics, immunotherapeutics, recombinant DNA technology, membrane biology and also as a diagnostic tool in different biological field. The enclosed phospholipid bilayer spherical structure, typically known as liposome, is a versatile vesicular delivery system to carry hydrophilic/hydrophobic drug generally efficiently to the site of action leading to reduced non-specific toxicity and improved bioavailability of the therapeutic moiety. Efficacy of drug encapsulated in liposome depends mainly on the circulation amount of liposome and its residence time, in vivo drug release, drug accumulation in the target site and uptake of the formulation in the reticuloendothelial system. Liposomal formulation factors that dictate those actions are liposomal size (hydrodynamic diameter), surface charge, lipid composition and steric stabilization. Variation in liposomal size shows around 100 fold alterations in pharmacokinetic parameters and systemic activity while the other factors such as surface charge, lipid composition and steric stabilization bring only about 10 fold changes in those properties. The findings indicate the critical role of vesicular size in liposomal efficacy. In the present review the effect of size-variation of liposome on systemic activity of drug as well as its pharmacokinetic profile will be discussed to understand the rational designing of liposomal preparation to maximize therapeutic activity of a drug at desired magnitude and to provide a wide range of product applications such as immunological vaccines, chemotherapy, antimicrobial therapy etc.

Most of the lipids of the skin surface come from sebaceous glands secretions, called sebum. Some of the sebum lipids are synthesized by sebaceous cells while some are reportedly derived from the plasma. Role of blood lipoproteins in sebum secretion rate and composition is unclear. To this end, excretion rate and composition of skin surface lipids of normo- and type IV hyperlipoproteinemic subjects were compared. Quantitative analysis of skin surface lipids was performed by three successive sampling on left, middle, and right zones of the forehead with a sebumeter. Skin surface lipid samples for the compositional analysis were collected from the forehead, extracted into n-hexane, and analyzed by high performance thin layer chromatography (HPTLC). HPTLC plates were scanned with a densitometer for the quantification of the lipids. Skin surface lipids from type IV hyperlipoproteinemic subjects contained higher proportion of wax ester + cholesterol ester compared with that from normolipoproteinemic subjects. However, skin surface lipid excretion rates of normo- and hyperlipoproteinemic subjects were found to be similar. Plasma lipid/lipoprotein concentration may be a determinant factor in sebum lipid composition.

The composition of the skin surface lipids of European cattle and buffalo steers