Evaluating Stability

While control and 2.5% organotin stabilizer containing films are transparent, films with 5% organotin stabilizer are opaque white, indicating limited solubility of organotin stabilizer in PVC.  

HCl Evolution from PVC and PVC with Z)/-n-Octyltin Bis(i -Octylthioglycollate) Stabilizer Films 

Cost constraints within which (1) and (2) must be constrained. 

Other formulation components which may interact with the stabilizer. 

Heiberger, Encyclopedia of Chemical Technology, Kirk-Othmer (Eds), 23, John Wiley and Sons, New York (1983). 

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In the discovery phase, a reaction route is developed to allow synthesis of a maximum number of analogues for pharmacological testing. Since the focus is on synthetic flexibility, issues of scale are not central. Once a lead compound exhibits a useful pharmacological activity and is identified as a candidate for further development, larger scale synthesis is required to evaluate stability, bioavailability, toxicity, physicochemical properties, and other compound properties. The Chemical Development Department is usually involved in the preparation of supplies for these activities. 

Because weak CL emission often is produced from the oxidation of many solid organic compounds, the measurement of this light emission may be used as an indicator of changes in materials composition due to oxidation processes, and for evaluating stabilizers intended to prevent or retard these oxidative alterations [6], Some examples of materials than can be characterized by CL emission are the polymers that are degraded by weathering, exposure to heat, or exposure to ionizing radiation, or food components that suffer flavor alterations. In this... 

Example 4 A Stability/Runaway Hazard Assessment Report In Table 2.3, test data evaluating stability/runaway hazards of a material are presented. This table contains the relevant test data and evaluations in accordance with Section 2.1.5 (Test Strategies) and represents a good model for summary reports of such key information. 

There are numerous types of TLC testing done in the pharmaceutical industry, which are quantitative in nature. Release testing or purity evaluation, stability testing, and LOD are the three that will be addressed here. 

The most common evaluation of aromaticity via energetic criteria is done using calculations either a type of isodesmic reaction (34) or comparison of two isomers that differ only through the aromaticity of one (3). We were interested in the possibility of evaluating stability experimentally and the electrochemical formation of dications such as 8 was attractive. In this approach, the redox potential for formation of the dication would be compared to the redox potential for formation of dications which could not be antiaromatic. If 8 was antiaromatic, its redox potential should be larger and more positive than that of the reference system. This approach was applied to the evaluation of the antiaromaticity of 9... 

Li and Wang described a convenient linear plotting protocol that permits one to evaluate stability constants for the formation of reversible metal hgand complexes. Added accuracy is achieved over classical approaches, because their generalized equations quantitatively account for side-reactions of metal ion and/or ligand as well as the difference between the total and free ligand concentration. 

We may conclude that significant progress has been made on the photo-electrocatalytic generation of H2, although it is not always possible to clearly identify when results due to are photoelectrolysis or photocatalytic splitting. The strong basic medium needed for photoelectrolysis further stresses the need to evaluate stability in long-term operations. 

Dean, D. A. (2000), Packaging, package evaluation, stability and shelf-life, in Carstensen, J. T., and Rhodes, C. T., Eds., Drug Stability, Principles and Practices, Marcel Dekker, New York, p. 483. 

Process capability evaluation Stability and variability of process output, economic limits... 

Selzer T, Radau M, Kreuter J. Use of isothermal heat conduction microcalorimetry to evaluate stability and excipient compatibility of a solid drug. Int J Pharm 1998 171 227-241. 

Again, poles and zeros are important for evaluating stability and controllability properties of the physical system. To find the poles of an open-loop MIMO system one can use the transfer function matrix or the state-space description. They are related by ... 

The colors were analyzed on a regular basis to evaluate stability, and microbiological contamination. Feed analyses were conducted on a weekly basis for the first 13 weeks of the study, and then at monthly intervals thereafter by the contract laboratory and by independent laboratories. Good laboratory practices monitoring occurred at least monthly. 

As the drug product enters subsequent clinical phases, materials are needed to support these clinical evaluations. Stability studies are necessary to support these materials. In most cases such smdies would only require long-term storage however, most companies conduct additional accelerated or stress studies on me clinical... 

It has generally been assumed that the bonds that link the catalyst to the polymer support are chemically stable under the reaction conditions one employs. Until recently, the literature offered little information in this regard, since lifetime studies are needed to properly evaluate stability. Recent publications have pointed out the chemical instability of the phosphorus-carbon bond of tertiary phosphine functionalized supports and the chemical reactivity of various nitrogen functionalized polymeric support materials under reaction conditions. If such chemical stability problems are present, the consequences are indeed serious. While a typical "leach" situation would necessitate a periodic reloading of the metal complex, cleavage of polymer functionality would necessitate replacement of both the metal complex and the polymer. 

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