Storage and Stability

Compare the refractive index of the substance to be examined with the refractive index of the reference standard of valproic acid, which has a known refractive index of 1.422-1.425 [10,11], 

Examine the test article by infrared absorption spectrophotometry, and compare with the spectrum obtained with a valproic acid reference standard [10,11]. 

Examine by thin-layer chromatography (TLC) using a suitable TLC silica gel as the coating substance on the TLC plate. The method requires preparation of the following solutions  

Test solution. Dissolve 50 mg of the substance to be examined in methanol and dilute to 5 mL with the same solvent. 

A crucial property of the analyte (and thus of the analytical standard) is its stability, both in the purified form and in solution. Relevant information pertaining to the stability of the pure compound, though not necessarily of the compound in solution in the chosen solvent, may be found on the Certificate of Analysis (Sections 2.2.2 and 9.4.4c). In many instances, instead of an expiration date a re-assay date will be provided. An extreme form of instability is the propensity of the analyte to explode or be set afire such properties should be available in the MSDS information and the Certificate of Analysis that should specify the appropriate storage conditions under which the stated expiration or re-assay date is valid. In any event, the reference standard should be stored under the same conditions that were used to establish stabdity and should not be used past the expiration or re-assay date unless other documentation is provided to substantiate the stability of the analyte under the storage conditions used. 

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The confirmatory procedure should be developed for the same tissues for which the determinative procedure was developed, preferably using the same extraction procedure as used for the determinative portion of the method. Storage and stability data are necessary for dried or liquid sample extracts if MS analyses of the confirmatory samples are to be conducted in a laboratory other than the laboratory of sample preparation. Analytes present in sample extracts must be stable long enough for the samples to be shipped to the MS laboratory and analyzed. 

Storage and Stability. It is obvious that practical explosives must possess long storage life. Kinetic data are most useful in evaluating the storage characteristics of an explosive, but they must be the right kind of data. 

Leermakers, M., Lansens, P. and Baeyens, W. (1990) Storage and stability of inorganic and methylmercury solutions. Fresenius J. Anal. Chem., 336, 655-662. 

R. J. Bayley and E. A. Evans, Storage and Stability of Compounds Labelled with Radioisotopes, Review 7, The Radiochemical Centre, Amersham, England (1968). 

There are a number of properties required for compounds to be suitable as precursors for MOVPE these include sufficient vapor pressure to allow suitable growth rates, abihty to be highly purified, controllable deposition behavior, stabihty in storage, and stability with other species during vapor-phase transport. 

Section 11, Stability and Storage Conditions, describes the conditions under which the bulk material as received from the supplier should be stored. In addition some monographs report on storage and stability of the dosage forms that contain the excipient. 

Storage and stability Toxin B is dissolved in 550 mM NaCI plus 50 mM Tris-HCI (pH 7.5), and toxin A in 250 mM NaCI plus 50 mM Tris-HCI (pH 7.5). After addition of glycerol (20%, v/v) the toxins are stored at -80°C. Repeated thawing and freezing should be avoided because of increased denaturation / inactivation of the toxins. At 4°C the toxins are stable for 2-3 weeks. 

Product storage and stability (or lack thereof) can bias clinical trials results, and dictate shelf-life in labeling. 

Continued vaccine studies are needed to determine the longevity of the protective immune response that is induced by recombinant RTA-based immunogens like RTAl-33/44—198 or RiVax. Additionally, it may be possible to develop RTA-based vaccines that combine the physicochemical advantages of the RTAl-198 platform for storage and stability with the desirable safety profile of RiVax. 

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