Spraying test methodology

The range of application of shear cell testing methodology is seen in Tables 2-6. Table 3 relates the flow properties of mixtures of spray-dried lactose and bolted lactose. These mixtures, in combination with the excipients tested, cover a broad range of flow. Tables 4 and 5, for example, show lot to lot variations in the flow properties of several materials, and Table 6 shows the variation in flow properties of bolted starch, sucrose, and phenacetin at different relative humidities (RH). Figure 8 presents the yield loci of sucrose at four different consolidation loads. Also shown in the figure are the shear indices determined at each consolidation load. 

It is imperative to also consult the vendor to determine an adequate number of valves for spray weight testing. If the metered chamber is plastic, valves totaling at least twice the number of the vendor s mold impressions should be tested to guarantee complete evaluation of the lot of valves. The spray weight methodology conducted on valves can drastically influence the results. Because the valve is a mechanical device, the way in which it is actuated is technique-oriented. Manual actuation versus automatic actuation can cause variation in the results. Method ruggedness is essential in evaluation of the valve performance. 

Publications on filiform test methodology are anticipated in the near future due to the current interest in aluminum for auto body sheet, together with the need to maintain an aesthetically pleasing painted surface. This form of corrosion can occur during exposure to seacoast atmosphere, and it has been developed at inland atmospheric exp>osure sites by spraying the specimens periodically (about three times per week) with a 3-5 % solution of sodium chloride. 

Finally, it is important to understand the limitations of each testing method [90], and that no one method will provide all of the necessary information. Thus, it is important to confirm rapid screening techniques with more traditional and industry-accepted methodologies such as weight loss tests or salt fog spray tests. For example, zinc phosphate has been shown to perform poorly in accelerated tests but generally well in exposure testing [47]. 

TLC is often used by BP monographs as part of a number of identity tests performed on pure substances. For extra confirmation of identity, more than one solvent system may be used and also different types of spray reagent may be used. Some examples of identity checks based on TLC have been mentioned earlier. Table 13.4 lists a few of the compounds which have their identity checked by TLC and a variety of location reagents and mobile phases are used to illustrate the fact that there is much less uniformity about TLC methodology than there is in the case of HPLC or GLC methodology. 

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