PEG is generally considered biologically inert and safe. However, studies of clinical safety are generally based on adults, not children. A minority of people are allergic to it. Allergy to PEG is usually discovered after a person has been diagnosed with an allergy to an increasing number of seemingly unrelated products, including processed foods, cosmetics, drugs, and other substances that contain PEG or were manufactured with PEG.Controllo finanziario e rischio di default. vol. 1. la
When PEG is chemically attached to therapeutic molecules such as protein drugs or nanoparticlesit can sometimes be antigenic, stimulating an anti-PEG antibody response in some patients. This effect has only been shown for a few of the many available PEGylated therapeutics, but it has significant effects on clinical outcomes of affected patients.
The three names are chemically synonymous, but historically PEG is preferred in the biomedical field, whereas PEO is more prevalent in the field of polymer chemistry. While PEG and PEO with different molecular weights find use in different applications, and have different physical properties e. Different forms of PEG are also available, depending on the initiator used for the polymerization process — the most common initiator is a monofunctional methyl ether PEG, or methoxypoly ethylene glycolabbreviated mPEG.
Lower-molecular-weight PEGs are also available as purer oligomers, referred to as monodisperse, uniform, or discrete. Very high purity PEG has recently been shown to be crystalline, allowing determination of a crystal structure by x-ray diffraction. The numbers that are often included in the names of PEGs indicate their average molecular weights e.
Most PEGs include molecules with a distribution of molecular weights i. Mw and Mn can be measured by mass spectrometry. PEGylation is the act of covalently coupling a PEG structure to another larger moleculefor example, a therapeutic proteinwhich is then referred to as a PEGylated protein.
PEG is soluble in watermethanolethanolacetonitrilebenzeneand dichloromethaneand is insoluble in diethyl ether and hexane.
It is coupled to hydrophobic molecules to produce non-ionic surfactants. PEGs potentially contain toxic impurities, such as ethylene oxide and 1,4-dioxane. Polyethylene glycol PEG and related polymers PEG phospholipid constructs are often sonicated when used in biomedical applications. However, as reported by Murali et al. It is, thus, imperative to assess potential PEG degradation to ensure that the final material does not contain undocumented contaminants that can introduce artifacts into experimental results.
PEGs and methoxypolyethylene glycols are manufactured by Dow Chemical under the tradename Carbowax for industrial use, and Carbowax Sentry for food and pharmaceutical use. They vary in consistency from liquid to solid, depending on the molecular weight, as indicated by a number following the name. They are used commercially in numerous applications, including as surfactantsin foods, in cosmeticsin pharmaceutics, in biomedicineas dispersing agents, as solvents, in ointmentsin suppository bases, as tablet excipientsand as laxatives.
Some specific groups are lauromacrogolsnonoxynolsoctoxynolsand poloxamers. Macrogolused as a laxative, is a form of polyethylene glycol.Freaktab s905x oreo
The name may be followed by a number which represents the average molecular weight e.PEG polyethylene glycol is a low-molecular-weight grade of polyethylene glycol. It is a clear, colorless, viscous liquid. Due in part to its low toxicity, PEG is widely used in a variety of pharmaceutical formulations. PEG is strongly hydrophilic. The partition coefficient of PEG between hexane and water is 0. PEG is soluble in water, acetone, alcohols, benzene, glycerin, glycols, and aromatic hydrocarbons, and is slightly soluble in aliphatic hydrocarbons.
From Wikipedia, the free encyclopedia. This article has multiple issues. Please help improve it or discuss these issues on the talk page. Learn how and when to remove these template messages. This article has an unclear citation style. The references used may be made clearer with a different or consistent style of citation and footnoting. November Learn how and when to remove this template message. The references in this article are unclear because of a lack of inline citations.
Help Wikipedia improve by adding precise citations! CAS Number. Chemical formula. LD 50 median dose. Ma; D. Hollander; P. Krugliak; K. Katz Categories : Polyethers.
We do not warrant neither express nor implied that the information in this chart is accurate or complete or that any material is suitable for any purpose. All Rights Reserved. Explanation of Footnotes 1. CAUTION: Variations in chemical behavior during handling due to factors such as temperature, pressure, and concentrations can cause equipment to fail, even though it passed an initial test. Download Printable.
Chemical Charts. Sign up to. Download Printable Chemical Charts.A solubility chart is a chart with a list of ions and how, when mixed with other ions, they can become precipitates or remain aqueous.
The following chart shows the solubility of multiple independent and various compounds, in water, at a pressure of 1 atm and at room temperature approx.Soluble and Insoluble Compounds Chart - Solubility Rules Table - List of Salts & Substances
Any box that reads "soluble" results in an aqueous product in which no precipitate has formed, while "slightly soluble" and "insoluble" markings mean that there is a precipitate that will form usually, this is a solidhowever, "slightly soluble" compounds such as calcium sulfate may require heat to form its precipitate. Boxes marked "other" can mean that many different states of products can result. For more detailed information of the exact solubility of the compounds, see the solubility table.
Note: All the dichromates are water-soluble. In a base, dichromates convert into chromates and some of the chromates are insoluble in water. From Wikipedia, the free encyclopedia.
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Solubility equilibrium Total dissolved solids Solvation Solvation shell Enthalpy of solution Lattice energy Raoult's law Henry's law Solubility table data Solubility chart. Category Acid dissociation constant Protic solvent Inorganic nonaqueous solvent Solvation List of boiling and freezing information of solvents Partition coefficient Polarity Hydrophobe Hydrophile Lipophilic Amphiphile Lyonium ion Lyate ion. Categories : Solutions.
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Here, we explored the utility of extrapolated solubility as a method to compare multiple protein drug candidates when nonideality of a highly soluble protein prohibits accurate quantitative solubility prediction. To achieve high efficiency and reduce the amount of protein required, the method is miniaturized to microwell plate format for high-throughput screening application. In this simplified version of the method, comparative solubility of proteins can be obtained without the need of concentration measurement of the supernatant following the precipitation step in the conventional method.
The monoclonal antibodies with the lowest apparent solubilities determined by this method are the most difficult to be concentrated, indicating a good correlation between the prediction and empirical observations. This study also shows that the PEG precipitation method gives results for opalescence prediction that favorably compares to experimentally determined opalescence levels at high concentration. This approach may be useful in detecting proteins with potential solubility and opalescence problems prior to the time-consuming and expensive development process of high concentration formulation.
Protein solubility is an important requisite for manufacture and administration of biological therapeutics. In particular, there is increasing demand for stable highly concentrated, liquid antibody formulations for subcutaneous s. There are many methods available for solubility measurement, including concentrating the protein solution by membrane-based ultrafiltration until a phase change precipitates or other solid forms is observed or by dissolving lyophilized protein powder to a high concentration solution.
Despite the fact that the experimental determination of solubility is relatively accessible, protein availability could be a limiting factor in many cases at the early stage of new drug development processes. The ability to predict protein potential for solubility would therefore be extremely beneficial for drug candidate selection and formulation screening.
It has been demonstrated that a log-linear relationship exists between protein solubility and weight percent polyethylene glycol PEG. As explained elsewhere, in high concentration protein solutions, the apparent solubility, derived from the intercept, comprises not only the intrinsic solubility term but also the thermodynamic nonideality term of the solution.
Here, we demonstrate an application of the prediction method despite the fact that it overestimates the protein solubility and present a novel evaluating technique to assess the likelihood of a protein to be a good candidate for a high concentration product. It provides an alternate knockout approach to identify protein candidates with potential for difficulty in reaching high concentration that could preclude development of dosage forms for subcutaneous administration.
In addition, this low volume high-throughput screening HTS technique can be utilized to improve efficiency of solubility screening and reduce the amount of protein needed. Previous literature has reported the precipitation method using PEG for predicting solubility of proteins, including antibodies. Here, we pose the question of whether this method still remains valid for predicting solubility characteristics when applied to relatively highly soluble proteins such as antibodies at pH away from their pIs.
Apparent solubility of mAb1 by PEG 10k. Some noticeable features when using the method of PEG-induced protein precipitation can be understood in accordance with Figure 1. Also, due to the highly soluble nature of monoclonal antibodies mAbs at a pH away from their pIs pH 6. Therefore, unlike previous studies, direct correlation of the predicted apparent solubility with protein actual solubility cannot be experimentally established for these highly soluble proteins.
In previous works, 37 authors point out that nonideal protein solutions give intercepts which include an activity related term representing the solution nonideality, and therefore exceed the practical solubility limits.
Consequently, care should be taken in interpretation of data for nonideal protein solutions. Protein solubility as a thermodynamic parameter is defined as the concentration of soluble protein that is in equilibrium with a crystalline solid phase under given conditions of pH, temperature, buffer concentration, and various additives.
Although the apparent solubility does not depict the actual solubility, we investigated whether the solubilities of different antibodies under the same buffer condition is a valid comparison. A visual microwell plate method was developed for rapid, HTS for apparent solubility using in-house mAbs. Due to the fact that the slope of the phase diagram remains constant for different mAbs data not showna simplified version of the PEG-based solubility assay was designed for HTS.What type of plastic offers the best resistance to various chemicals?
Chemical Resistance Reference Charts for Plastic Containers: We have several chemical compatibility reference charts to help you determine the appropriate resin for your specific chemical needs.
We have aggregated this data from dozens of sources and any single piece of data cannot be guaranteed. It is your responsibility to test a container and chemical together ensure compatibility under your unique circumstances.
Home Chemical Charts Chemical Charts What type of plastic offers the best resistance to various chemicals?Il controllo statistico di qualita 1. introduzione
Polyethylene HDPE and LDPE has a very good compatibility rating with most chemicals and is resistant to strong acids and bases, as well as gentle oxidants and reducing agents Polypropylene is almost as resistant as polyethylene, but with a few specific chemicals it offers superior resistance. It can also be autoclaved and is better for use in higher temperature situations.
PTFE is the most chemically resistant resin, although it is much more expensive and appropriate only for extreme acids and oxidizers that cannot be stored in more economical plastics Steel and Stainless Steel should be used with fuels and flammables that require grounding Chemical Resistance Reference Charts for Plastic Containers: We have several chemical compatibility reference charts to help you determine the appropriate resin for your specific chemical needs.
Sign up to. Download Printable. Chemical Charts. Download Printable Chemical Charts. Some effect after 7 days to the reagent. The effect may be crazing, cracking, loss of strength or discoloration. Not recommended. Immediate damage may occur. Depending on the plastic, the effect may be severe crazing, cracking, loss of strength, discoloration deformation, dissolution or permeation loss.
Not recommended for continuous use. LDPE not recommended at any temperature.The American Institute for Conservation Solubility Parameters: Theory and Application John Burke Solvents are ubiquitous: we depend on them when we apply pastes and coatings, remove stains or old adhesives, and consolidate flaking media. The solubility behavior of an unknown substance often gives us a clue to its identification, and the change in solubility of a known material can provide essential information about its ageing characteristics.
Our choice of solvent in a particular situation involves many factors, including evaporation rate, solution viscosity, or environmental and health concerns, and often the effectiveness of a solvent depends on its ability to adequately dissolve one material while leaving other materials unaffected.
The selection of solvents or solvent blends to satisfy such criterion is a fine art, based on experience, trial and error, and intuition guided by such rules of thumb as "like dissolves like" and various definitions of solvent "strength". While seat-of-the-pants methods are suitable in many situations, any dependence on experiential reasoning at the expense of scientific method has practical limitations.
Although it may not be necessary to understand quantum mechanics to remove masking tape, an organized system is often needed that can facilitate the accurate prediction of complex solubility behavior. Solubility Scales Product literature and technical reports present a bewildering assortment of such systems: Kaouri-Butanol number, solubility grade, aromatic character, analine cloud point, wax number, heptane number, and Hildebrand solubility parameter, among others.
In addition, the Hildebrand solubility parameter, perhaps the most widely applicable of all the systems, includes such variations as the Hildebrand number, hydrogen bonding value, Hansen parameter, and fractional parameter, to name a few.
Sometimes only numerical values for these terms are encountered, while at other times values are presented in the form of two or three dimensional graphs, and a triangular graph called a Teas graph has found increasing use because of its accuracy and clarity.
Understandably, all this can be slightly confusing to the uninitiated. Graphic plots of solvent-polymer interactions allow the fairly precise prediction of solubility behavior, enabling the control of numerous properties in practical applications that would be very difficult without such an organizing system. Yet the underlying theories are often extremely complex, and an understanding of the "why" of a particular system can be very difficult, enough to discourage the use of such systems.
Many of the systems mentioned, however, are actually quite simple this is especially true of the Teas graph and can be used to advantage with little understanding of the chemical principles at work.Vw 02m sequential gearbox
This paper will attempt to bridge these two realities by briefly introducing solubility theory as well as its application so that the conservator will be both better able to understand and profitably apply the concepts involved. The discussion will center on Hildebrand solubility parameters and, after laying a theoretical foundation, will concentrate on graphic plots of solubility behavior.
It should be remembered that these systems relate to non-ionic liquid interactions that are extended to polymer interactions; water based systems and those systems involving acid-base reactions cannot be evaluated by simple solubility parameter systems alone. Solutions and Molecules A solventusually thought of as a liquid, is a substance that is capable of dissolving other substances and forming a uniform mixture called a solution.
The substance dissolved is called the solute and is usually considered to be the component present in the smallest amount. According to this definition, an almost-dry or slightly swollen resin film comprises a solution of a liquid the solute in a resin the solventeven though conventionally the liquid is usually referred to as the solvent, and the resin as the solute.
Molecular Attractions Liquids and solids differ from gases in that the molecules of the liquid or solid are held together by a certain amount of intermolecular stickiness.
For a solution to occur, the solvent molecules must overcome this intermolecular stickiness in the solute and find their way between and around the solute molecules. At the same time, the solvent molecules themselves must be separated from each other by the molecules of the solute. This is accomplished best when the attractions between the molecules of both components are similar.
If the attractions are sufficiently different, the strongly attracted molecules will cling together, excluding the weakly attracted molecules, and immiscibility not able to be mixed will result.
Oil and water do not mix because the water molecules, strongly attracted to each other, will not allow the weakly, attracted oil molecules between them. Van der Waals Forces These sticky forces between molecules are called van der Waals forces after Johannes van der Waals who first described them in Originally thought to be small gravitational attractions, Van der Waals forces are actually due to electromagnetic interactions between molecules.
The outer shell of a neutral atom or molecule is composed entirely of negatively charged electrons, completely enclosing the positively charged nucleus within.
Deviations in the electron shell density, however, will result in a minute magnetic imbalance, so that the molecule as a whole becomes a small magnet, or dipole. These electron density deviations depend on the physical architecture of the molecule: certain molecular geometries will be strongly polarwhile other configurations will result in only a weak polarity.
These differences in polarity are directly responsible for the different degrees of intermolecular stickiness from one substance to another. Substances that have similar polarities will be soluble in each other but increasing deviations in polarity will make solubility increasingly difficult. Van der Weals forces, then, are the result of intermolecular polarities. As we shall see, accurate predictions of solubility behavior will depend not only on determining the result of intermolecular attractions between molecules, but in discriminating between different types of polarities as well.
A single molecule, because of its structure, may exhibit van der Waals forces that are the additive result of two or three different kinds of polar contributions. Substances will dissolve in each other not only if their intermolecular forces are similar, but particularly if their composite forces are made up in the same way.
Such types of component interactions include hydrogen bonds, induction and orientation effects, and dispersion forces, which will be discussed later.
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