Specification stability

Catalysts serve a dual purpose in one-component moisture-curing urethanes. The first purpose is to accelerate the prepolymer synthesis. The second purpose is to catalyze the curing reaction of the adhesive with moisture. The most common catalysts used to promote both prepolymer formation (NCO/OH) and later the adhesive curing reaction (NCO/H2O) are dibutyltin dilaurate and DMDEE ((tertiary amine. A stabilizer such as 2,5-pentanedione is sometimes added when tin is used, but this specific stabilizer has fallen from favor in recent years, due to toxicity concerns. DMDEE is commonly used in many one-component moisture-curing urethanes. DMDEE is one of the few tertiary amines with a low alkalinity and a low vapor pressure. The latter... 

A related preparation of specific stabilized phosphonium yUdes corresponds to the reaction of triarylphosphines with acetylene dicarboxylic esters in presence of fullerene, which affords a cyclopropanyl-fullerene substituted stabilized phosphonium ylide [9] or the corresponding evolution products [10]. 

In the production of aerated confections it is very important to add various hydrocolloids, in order to obtain a foam which will withstand the specific stability requirements of the specialty food product involved. 

S. J. Perstrelski, T. Arakawa, and J. F. Carpenter, Separation of freezing and drying-induced denaturation of lyophilized proteins using stress-specific stabilization. II. Structural studies using infrared spectroscopy, Arch. Biochem. Biophys., 303, 465... 

MD simuations on low-energy [9-H-A] (A = alanine) docking geometries point to EXT as the thermodynamically most favored structures at room temperature. The relevant diastereomeric structures are almost equally stable. Therefore, the observed enantioselectivity has to be attributed to specific stabilization of the exhange transition structures. In this view, the small effects of the configuration of B Sb = (kfi/ks in Table 17) indicates that the B amine displaces alanine from the relevant EXT structure without getting completely into the chiral cavity of the host. 

It should be noted that some commercial enzyme preparations may contain several enzyme isomers (enzymes derived from one source which belong to the same enzyme class but differ in specificity, stability or other properties). This is most often the case when the commercial preparation was developed for a process industry application rather than a specific chemical biotransformation application. Some fungal enzymes, such as laccase, are sometimes supplied as crude enzyme mixtures. Fungal laccases are manufactured on a huge scale (multitonne per annum) and are principally used in bulk processes such as wood... 

In the absence of specific stability guidance from the FDA and ICH (and limited guidance from the WHO) for excipients, the USP GMP guidance for bulk pharmaceutical excipients [4] is used to review stability requirements for excipients. A... 

Credible pharmaceutical product expiration dates are obtained by rigorous, scientifically designed studies using reliable, meaningful, and specific stability-indicating assays, appropriate statistical concepts, and computers to analyze the resulting data [2]. A comprehensive review of all aspects of pharmaceutical product stability has been published by Lintner [3] and more recently by Connors et al. [4]. 

Supramolecular control of reactivity and catalysis is among the most important functions in supramolecular chemistry. Since catalysis arises from a differential binding between transition and reactant states, a supramolecular catalyst is, in essence, chemical machinery in which a fraction of the available binding energy arising from noncovalent interactions is utilized for specific stabilization of the transition state or, in other words, is transformed into catalysis. 

This study demonstrates by a novel method the enhancement of hydrophobic forces. New data are presented to support the suggestion that dispersion forces specifically stabilize the IIS aggregate and that hydrophobic forces are not substantially altered by deuteration at nonexchangeable sites. 

If a third component (M), which can specifically stabilize one of the products of electron transfer, is introduced into the D -A system, the free energy change of photoinduced electron transfer is shifted to the negative direction, when the activation barrier of electron transfer is reduced to accelerate the rates of electron transfer, as shown in Figure 3, where M forms a complex with A ". It should be emphasized that there is no need to have an interaction of M with A and that the interaction with the reduced state (A ") is sufficient to accelerate the rate of photoinduced electron transfer. This contrasts sharply with the catalysis on conventional ionic or concerted reactions, in which the catalyst interacts with a reactant to accelerate the reactions. The initial interaction between M and A in the complex A-M, where charge is partially transferred from A to M, would also result in acceleration of the photoinduced electron transfer, since the reduction potential of A-M is shifted to the negative direction as compared to that of A. 

ED treatment may be tailored for any type of wine by referring to a specific stability test. A sample of the raw wine under testing is to be filtered,... 

It is best to establish specific stabilization parameters and their performance criteria for each well based on such factors as the aquifer properties the well construction detail the nature of contaminants of concern the sampling technique and field instrument specifications. However, this may be achievable only for wells with historical data on a long-term monitoring program. As a general practice, we may use the guidelines for the stabilization parameter criteria presented in Table 3.4. 

Awell-designed stability program has many aspects. Some aspects are general and best addressed in a stability program SOP. Other aspects are specific and best described in product-specific stability protocols. 

A product-specific stability protocol supplements the information provided in the stability program SOP. In some instances, the requirements in a product-specific stability protocol may differ from those specified in the stability program SOP for scientific, regulatory, or business reasons. In all cases, aproduct-specific stability protocol takes precedence over the general stability program SOP. The product-specific stability protocol should clearly define and justify both the conditions to be used and any deviations from the stability program SOP, including reason and justification. 

A product-specific stability protocol should include the items outlined in Example 14. 

---