Lack of standard test

At present, despite the advantages offered by the buccal delivery route, such as the bypass of intestinal and hepatic first-pass metabolism for systemic delivery, very few pharmaceutical products employ this route of administration. The reasons that contribute to this situation include (1) high costs associated with development, (2) lack of standardized tests to identify drug candidates suitability for this route, (3) the limited understanding of the impact of metabolism and/or transporters found in the oral cavity mucosa on buccal delivery, and (4) the relatively small number of reports describing the usefulness and safety of excipients/permeation enhancers in humans [82, 83], Therefore, the... 

Generally, vulcanised rubber is dimensionally very stable (unless it is strained), which probably explains the lack of standard test methods for this property. In this context, thermal expansion and swelling in liquids are properties considered in their own right and not normally thought of as being measures of dimensional stability. This is a different situation to that which exists with plastics where a number of dimensional stability tests are in existence. If a measure of dimensional change is required, the appropriate dimensions of a suitable sized test piece can be measured by any of the methods mentioned in this chapter before and after an ageing treatment. 

The assays most widely employed are the measurement of thiobarbituric acid-reactive species (TBARS) and the formation of conjugated dienes, markers of lipid peroxidation [31-33] the determination of advanced oxidation protein products (AOPP), a marker of protein oxidation, and of advanced glycation end-products (AGE) [34-37] the measurement of erythrocyte antioxidant potential [38]. Of particular importance is the isoprostanes determination, since these compounds are formed by the free radical catalysed peroxidation of arachidonic acid, which is independent of the cyclooxygenase enzyme, giving rise to stable compounds, measurable in urine [39]. As recently assessed in a Workshop on markers of oxidative damage and antioxidant protection [40], currently available methods for the determination of antioxidant and redox status are not yet generally suitable for routine clinical applications, essentially for the lack of standardized tests. 

It was natural that the first efforts to develop uniform testing procedures for the selection of compatible materials should come out of the oxygen industry which has always been concerned about the use of lubricants (or anti-friction compounds, as they prefer to call them) in oxygen systems. The reasons for their concern include (1) the possible use of petroleum lubricants (2) the lack of assurance concerning the quality and uniformity of the available lubricating materials (3) the lack of consumer knowledge about the use and methods of application and (4) the lack of standard test specifications to qualify the suita-... 

The type of food and its processing affect flavoring efficiency therefore, flavor materials must be taste-tested in the food itself. Because there has been a lack of standardization of testing techniques, a committee on sensory evaluation of the Institute of Food Technologists has offered a guide (112) which is designed to help in developing standard procedures. 

Figure 30 portrays the grid of values of the independent variables over which values of D were calculated to choose experimental points after the initial nine. The additional five points chosen are also shown in Fig. 30. Note that points at high hydrogen and low propylene partial pressures are required. Figure 31 shows the posterior probabilities associated with each model. The acceptability of model 2 declines rapidly as data are taken according to the model-discrimination design. If, in addition, model 2 cannot pass standard lack-of-fit tests, residual plots, and other tests of model adequacy, then it should be rejected. Similarly, model 1 should be shown to remain adequate after these tests. Many more data points than these 14 have shown less conclusive results, when this procedure is not used for this experimental system.

There are a number of factors contributing to this discrepancy, such as a lack of standardization in specimen preparation, the loading method, the measurement and data reduction methods. Details of major contributors to the large data scatter are summarized for each testing method in the following ... 

Currently, most INDs are submitted in paper form, often accompanied by an electronic disk with hyperlinks. Purely electronic submissions are still rare, in large part because of a lack of standardization and electronic sophistication on the part of the FDA. There is currently a Clinical Data Interchange Standards Consortium (CDISC) test underway assuming it proves successful, it is likely that CD ISC will emerge as a common electronic submission standard for INDs, New Drug Applications (NDAs), and Abbreviated New Drug Applications (ANDAs) over the next three to five years. 

There have been several schools of thought as to the reason why IHC stains are difficult to run in a reproducible or consistent manner. If there is a consensus as to the cause of lack of standardization, it is that several reasons conspire together. These may conveniently be grouped into three general areas as presented in Table 1, that summarizes those factors that must come together to produce the Total Test (10, 16). 

Lack of standards in testing for refractories becomes apparent when one realizes that factors such as sample size and geometry, state of stress in the lining, thermal gradient, thermal cycling and duration are difficult to scale down to a laboratory scale to simulate service conditions. Accelerated tests involving severe conditions do not always conform to realistic conditions and may lead to unrealistic results. 

Oxidation of iodide ion has enjoyed popularity largely as a test of theories of salt effects. Studies of the rates in mainly aqueous solutions " and in mixed solvents provide good examples of struggles with insufficient sensitivity (here of the starch, iodine, iodide system), with persistent catalytic impurities, with inadequate or inaccurate description of procedures and results and with repetition which became necessary because of lack of standardization of conditions, all of which cause frequent frustration in kinetic investigations. The... 

In the stool test, specific H. pylori antigens are detected in microtiter plates coated with polyclonal antibodies. Debate continues regarding its accuracy for assessing treatment outcome some of the variability in results between different studies appears to be caused by lack of standardization of the interval between completion of eradication therapy and stool testing.However, the test is currently recommended for posteradication testing if the urea breath test is not available. 

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