Stability assessment

Stability Assessment In general there is no formal stability study prior to the certification of a natural matrix S RM. H owever, the stability of the certified analytes is monitored on a regular basis, typically every 1-3 years depending on the analytes, as the SRMs are analyzed as control samples during the analyses of similar matrix samples. A recent study of PAHs in frozen mussel tissue over nearly 10 years found no significant changes in the concentrations of the measured PAHs (Schantz et al. 2000). 

Colloid stability assessments of silica dispersions in CCI4 by sediment volume and coagulation rate are in general concordance and confirm the pattern previously reported by Barron and Howard... 

The evaluation process is completed with a thermal stability assessment of the products within the process temperature and time ranges. This assessment includes possible interactions of the products with the materials of construction of the equipment used. The methodology is the same as the one previously described for the reactants. It needs to be emphasized that depending on the circumstances the investigation cannot be limited to the pure products. Sometimes representative samples of reaction mixtures at different conversion stages need to be assessed as well. 

ITABLE 4.5. Some analytical techniques use in protein characterization and stability assessment... 

McIntosh, K.A., S.A. Charman, L.A. Borgen, and W.N. Charman, Analytical methods and stability assessment of liquid yeast derived sucrose. J Pharm Biomed Anal, 1998.17(6-7) 1037-45. 

Merkli, A., Heller, J., Tabatabay, C., and Gumy, R. (1996). Purity and stability assessment of a semi-solid poly(ortho ester) used in drug delivery systems. Biomaterials, 17, 897-902. 

Excipient compatibility studies are a form of preliminary stability assessment. It is important that they be executed appropriately. The precise details of the testing will probably be different for each organization carrying out such studies. However, certain general assumptions are implicit in this approach. The underlying principle is the Arrhenius relationship ... 

Freeze-thaw stability due to reasonable probability this might be necessary for repeat studies bench-top stability assessment may be prudent for chemical series with known temperature instability... 

Olsen BA, Perry FM, Snorek SV, Lewellen PL. Accelerated conditions for stability assessment of bulk and formulated cefaclor monohydrate. Pharm Dev Technol 1997 2(4) 303-312. 

The stability is another critical aspect for RM use it has to be verified in relation to the purpose of the study, e.g. over the duration of an interlaboratory study, or over long-term storage periods (for CRMs). The (in)stability should be studied or known before the RM is produced and should be monitored on the batch of RM. Studies may be performed under accelerated ageing conditions, e.g. elevated temperatures, or at various temperatures over defined periods of time. The BCR has developed a strategy with respect to stability assessment which has been successfully used for a wide variety of chemical species as described later in this chapter. Full details on the organisation of such studies are described elsewhere (Quevauviller et al., 1996a Quevauviller, 1998b). 

Bilati U, Pasquarello C, Corthals GL, et al. Matrix-assisted laser desorption/ioniza-tion time-of-flight mass spectrometry for quantitation and molecular stability assessment of insulin entrapped within PLGAnanoparticles./. Pharm. Sci. (2005) 94 688-694. 

Back Logroll as a unit to inspect back maintain spinal alignment during examination observe for bruising and open wounds palpate each vertebral body for fenderness, pain, deformity, and stability assess flank area for bruising and tenderness. 

We performed experimental research on stability assessment of RVX and identification of its transformation products under the action of equimolar or excess amoimts of water. The method for analysis was GC-EIMS. In a dilute aqueous solution (lOmg/ml) in the presence of 5% phosphoric acid, the concentration of RVX after exposiue for 20 days at room temperature without stirring was 2.7 mg/ml or 27% of the initial amoimt. Since among RVX hydrolysis products both volatile and nonvolatile compounds could be expected, we ehose three schemes for sample preparation ... 

R. Xu, E. Duchoslav, A. Aparicio, E. B. Jones, and D. B. Kassel, Streamlined approaches to metabolic stability assessment and metabolite profiling in drug discovery, in 51st ASMS Conference on Mass Spectrometry and Allied Topics, Montreal, Canada, Book of Abstracts, ASUS, 2003. 

---