Pure Cholesterol Bilayer Domains are Formed at Cholesterol Contents Significantly Lower than Cholesterol Solubility Thresholds in Phospholipid Membranes: EPR and DSC Studies

The plasma membranes of the human lens fiber cell are overloaded with cholesterol that not only saturates the phospholipid bilayer of these membranes but also leads to the formation of pure cholesterol bilayer domains. Cholesterol level increases with age, and for older persons, it exceeds the cholesterol solubility threshold, leading to the formation of cholesterol crystals. All these changes occur in the normal lens without too much compromise to lens transparency. If the cholesterol content in the cell membranes of other organs increases to extent where cholesterol crystals forma, a pathological condition begins. In arterial cells, minute cholesterol crystals activate inflammasomes, induce inflammation, and cause atherosclerosis development. In this review, we will indicate possible factors that distinguish between beneficial and negative cholesterol action, limiting cholesterol actions to those performed through cholesterol in cell membranes and by cholesterol crystals.

Download Full-text

Proposals for the ISS: «Liposomes» Experiment Influence of microgravity on structural and functional properties of artificial phospholipid membranes

Kosmìčna nauka ì tehnologìâ ◽

10.15407/knit2000.04.941 ◽

2000 ◽

Vol 6 (4) ◽

pp. 94-94 ◽

Cited By ~ 1

Author(s):

T.A. Borisova

Keyword(s):

Functional Properties ◽

Phospholipid Membranes ◽

Structural And Functional Properties

Download Full-text

Faculty Opinions recommendation of Hydration interaction between phospholipid membranes: insight into different measurement ensembles from atomistic molecular dynamics simulations.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718205837.793488403 ◽

2013 ◽

Author(s):

Nathan Baker ◽

Jaehun Chun

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulations ◽

Phospholipid Membranes ◽

Dynamics Simulations ◽

Insight Into

Download Full-text

Characterization and Screening of a Novel Multiparticulate Pulsatile Delivery of Aceclofenac

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2016.9.5.7 ◽

2016 ◽

Vol 9 (5) ◽

pp. 3494-3501

Author(s):

Bipul Nath ◽

Santimoni Saikia

Keyword(s):

Drug Release ◽

Sodium Alginate ◽

Alginate Beads ◽

In Vitro Drug Release ◽

Dsc Studies ◽

Ft Ir ◽

Lag Period ◽

Pulsatile Delivery ◽

Ca Alginate

In the present investigation, sodium alginate based multiparticulate system overcoated with time and pH dependent polymer was studied in the form of oral pulsatile system to achieve pulsatile with sustained release of aceclofenac for chronotherapy of rheumatoid arthritis seven batches of micro beads with varying concentration of sodium alginate (2-5 %) were prepared by ionotropic-gelation method using CaCl2 as cross-linking agent. The prepared Ca-alginate beads were coated with 5% Eudragit L100 and filled into pulsatile capsule with varying proportion of plugging materials. Drug loaded microbeads were investigated for physicochemical properties and drug release characteristics. The mean particle sizes of drug-loaded microbeads were found to be in the range 596±1.1 to 860 ± 1.2 micron and %DEE in the range of 65-85%. FT-IR and DSC studies revealed the absence of drug polymer interactions. The release of aceclofenac from formulations F1 to F7 in buffer media (pH 6.8) at the end of 5h was 65.6, 60.7, 55.7, 41.2, 39.2, 27 and 25% respectively. Pulsatile system filled with eudragit coated Ca-alginate microbeads (F2) showed better drug content, particle size, surface topography, in-vitro drug release in a controlled manner. Different plugging materials like Sterculia gum, HPMC K4M and Carbopol were used in the design of pulsatile capsule. The pulsatile system remained intact in buffer pH 1.2 for 2 hours due to enteric coat of the system with HPMCP. The enteric coat dissolved when the pH of medium was changed to 7.4. The pulsatile system developed with Sterculia gum as plugging material showed satisfactory lag period when compared to HPMC and Carbopol.

Download Full-text

Solubility Enhancement of Poorly Water-Soluble Antifungal Drug Acyclovir by Nanocrystal Formulation Approach

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2018.11.2.5 ◽

2018 ◽

Vol 11 (2) ◽

pp. 4036-4042

Author(s):

Prakash Goudanavar ◽

Ankit Acharya ◽

Vinay C.H

Keyword(s):

Chemical Interaction ◽

Research Work ◽

Antiviral Drug ◽

In Vitro Release ◽

Oral Route ◽

Water Soluble ◽

Precipitation Method ◽

Dsc Studies ◽

Ft Ir

Administration of an antiviral drug, acyclovir via the oral route leads to low and variable bioavailability (15-30%). Therefore, this research work was aimed to enhance bioavailability of acyclovir by nanocrystallization technique. The drug nanocrystals were prepared by anti-solvent precipitation method in which different stabilizers were used. The formed nanocrystals are subjected to biopharmaceutical characterization including solubility, particle size and in-vitro release. SEM studies showed nano-crystals were crystalline nature with sharp peaks. The formulated drug nanocrystals were found to be in the range of 600-900nm and formulations NC7 and NC8 showed marked improvement in dissolution velocity when compared to pure drug, thus providing greater bioavailability. FT-IR and DSC studies revealed the absence of any chemical interaction between drug and polymers used.

Download Full-text

Structural Characterization of Gallbladder Stones Using Energy Dispersive X-ray Spectroscopy and X-ray Diffraction

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207321666180913113803 ◽

2018 ◽

Vol 21 (7) ◽

pp. 495-500 ◽

Cited By ~ 1

Author(s):

Hassan A. Almarshad ◽

Sayed M. Badawy ◽

Abdalkarem F. Alsharari

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Energy Dispersive ◽

Spectroscopic Techniques ◽

X Ray Diffraction ◽

Major Health Problem ◽

X Ray ◽

Gallbladder Stones ◽

Pure Cholesterol ◽

Scanning Electron

Aim and Objective: Formation of the gallbladder stones is a common disease and a major health problem. The present study aimed to identify the structures of the most common types of gallbladder stones using X-ray spectroscopic techniques, which provide information about the process of stone formation. Material and Method: Phase and elemental compositions of pure cholesterol and mixed gallstones removed from gallbladders of patients were studied using energy-dispersive X-ray spectroscopy combined with scanning electron microscopy analysis and X-ray diffraction. Results: The crystal structures of gallstones which coincide with standard patterns were confirmed by X-ray diffraction. Plate-like cholesterol crystals with laminar shaped and thin layered structures were clearly observed for gallstone of pure cholesterol by scanning electron microscopy; it also revealed different morphologies from mixed cholesterol stones. Elemental analysis of pure cholesterol and mixed gallstones using energy-dispersive X-ray spectroscopy confirmed the different formation processes of the different types of gallstones. Conclusion: The method of fast and reliable X-ray spectroscopic techniques has numerous advantages over the traditional chemical analysis and other analytical techniques. The results also revealed that the X-ray spectroscopy technique is a promising technique that can aid in understanding the pathogenesis of gallstone disease.

Download Full-text

Development and Characterization of LBG-PVA Interpenetrating Networks Incorporating Gliclazide for Sustained Release

Current Drug Therapy ◽

10.2174/1574885515999200719143513 ◽

2020 ◽

Vol 15 ◽

Author(s):

Ashish Katoch ◽

Manju Nagpal ◽

Malkiet Kaur ◽

Manjinder Singh ◽

Geeta Aggarwal ◽

...

Keyword(s):

Solid State ◽

Sustained Release ◽

Half Life ◽

Solid State Nmr ◽

Oral Dosage ◽

Cross Linking ◽

Interpenetrating Networks ◽

Dsc Studies ◽

Biological Half Life ◽

Percentage Yield

Background: Controlled oral dosage forms have always been preferred for drugs with variable absorption, and short biological half life and frequent dosing. The prime goal with sustained release systems is to maintain uniform therapeutic blood levels for longer periods of time. Interpenetrating networks (IPNs) have been evidenced as uniform sustained release systems. In current study, polyvinyl alcohol (PVA) and locust bean gum (LBG) based IPNs were developed for the oral sustained release drug delivery of gliclazide (shows variable absorption). Method: The IPNs were synthesized by emulsion cross-linking method using glutaraldehyde (GA) as a cross linking agent. Gliclazide is a potential second generation, short-acting sulfonylurea oral hypoglycemic agent is having a short biological half-life (2-4 h), variable absorption and poor oral bioavailability. Various batches of IPNs were formulated by varying LBG: PVA ratio and evaluated for percentage yield, drug entrapment efficiency (DEE), swelling properties and in vitro drug release studies. Further characterizations were done by Fourier Transform Infrared Spectroscopy (FTIR), C13 Solid state NMR, X-Ray diffraction study (XRD), Scanning electron microscopy (SEM), and Differential scanning microscopy (DSC) studies. Results: The percentage yield, drug entrapment and equilibrium swelling was observed to be dependent on PVA-LBG ratio and GA amount. Sustained release of drug was observed in all IPN formulations (approx 59 - 86% in 8 h in various batches) with variable release kinetics. SEM studies revealed the regular structures of IPNs. FTIR, XRD, C13 Solid state NMR and DSC studies proposed that drug was successfully incorporated into the formed IPNs. Conclusion: IPNs of LBG and PVA can be used as a promising carrier with uniform sustained release characteristics.

Download Full-text