Carbonyl

Wang et al. (2015) formulated a solid dispersion to improve the solubility and bioavailability of Ginkgo biloba extract (GE) through hot melt technology. The polymer studied were Kollidon® VA64/Kolliphor® RH40 (85:15) and the extrusion was carried out at 120-125⁰C with 100 RPM with 25% drug load. DSC and XRD studies confirmed the amorphous conversion of the GE and the dissolution carried in 250ml of 0.1N HCl showed that the dissolution of solid dispersion of GE was significantly improved (2-3…

Both IR and UV spectroscopy are methods of measuring the wavelengths absorbed by a tested material. IR spectroscopy measures the absorbance of the tested material in the infrared spectrum, the section of the electromagnetic spectrum with a lower frequency than that observed in the visible light spectrum. Conversely, UV spectroscopy measures the absorbance of the tested material in the ultraviolet spectrum, the section of the electromagnetic spectrum with a higher frequency than that observed in…

Draw resonance structures showing all the positions at which the positive charge is delocalized on the aromatic ring in the phenonium ion. If a methoxy group (-OCH3) or a nitro group (–NO2) were substituted in the 4-position on the aromatic ring, how would the stability of the phenonium ion change? Compare methoxy substituted, nitro substituted and unsubstituted, and order them by increasing stability. Explain your answer thoroughly. 2) Benzopinacol and benzopinacolone have nearly…

Dyslipidemia is a prominent factor for the development of cardiovascular diseases that are the leading cause of death in the world, with left ventricular hypertrophy being one of these. Changes in the lipid profile are also responsible for the oxidative stress that affects several organs, and the liver is one of the most affected. Such involvement triggers diseases that affect the organ structurally and functionally. Herbal medicines in recent years are emerging as an alternative in the…

The goal of this lab was to prepare methyl m-nitrobenzoate using electrophilic aromatic substitution. An example of electrophilic aromatic substitution is nitration where a hydrogen atom which is part of a aromatic ring is substituted by an electrophile. For benzene, aromaticity is a stabilizing feature. As such, instead of undergoing electrophilic additions, it undergoes electrophilic substitutions. The nitronium ion is the electrophile which gets attached to the electron rich aromatic…

When Kevlar is spun, the resulting fiber has a tensile strength of about 3,620 MPa,[13] and a relative density of 1.44. The polymer owes its high strength to the many inter-chain bonds. These inter-molecular hydrogen bonds form between the carbonyl groups and NH centers. Additional strength is derived from aromatic stacking interactions between adjacent strands. These interactions have a greater influence on Kevlar than the van der Waals interactions and chain length that typically influence the…

CHAPTER 4 RESULT AND DISCUSSION 4.1 Preparation of Bis-Thiourea Derivatives The mixture of heptanoyl chloride and ammonium thiocynate with 1,4-phenylene diamine appeared as homogeneous solution. White precipitate was formed immediately when the solution was filtered into the beaker containing ice cubes. Then, the precipitate was filtered again and rinsed by ethanol before being dried in the desiccator. The physical data of the synthesized bis-thiourea derivatives are shown in Table 4.1.…

An insight in the biophysical properties of bio macromolecules Natural biopolymers such as nucleic acids, proteins and carbohydrates are essential for life as we see it today. It is incredible to think how this vast set of molecules that are in every living thing, from bacteria to human beings, are mostly made up by six elements (carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorus). These biopolymers have the properties to, from small monomers, build giant tridimensional structures with a…

consisting of four linked hydrocarbon rings forming the bulky steroid structure. There is a hydrocarbon tail linked to one end of the steroid and a hydroxyl group linked to the other end. The hydroxyl group is able to form hydrogen bonds with nearby carbonyl oxygen of phospholipid and sphingolipid headgroups.Cholesterol is referred as an amphipathic molecule, that it contains its hydrophilic and hydrophobic parts. Cholesterol is usually synthesized in animals and smaller cholesterol can be…

1.1 General Evaporation is the process by which water is converted into gaseous state and is returned to the atmosphere as vapour. Evaporation is an important process in the hydrologic cycle preceding precipitation. It is the process by which water in the liquid form transforms into vapour through the transfer of energy. When water is converted from solid state to vapour state without passing through liquid state then it is called sublimation. In the atmosphere, evaporation occurs from the water…