Turbidimetric assay

Shihabi, Z. R. and Bishop, C. Simplified turbidimetric assay for lipase activity. Clin. Chem. (1971), 17 1150-1153. 

To evaluate the influence of structural parameters governed by the cyclophosphazene core concerning the valency and the spatial orientation of epitopes, as well as the nature of linkers directly related to the ligation technique used for the mannoside incorporation, the authors performed preliminary kinetic turbidimetric assays with Con A. Insoluble cross-linked complexes formed rapidly for all compounds, without marked difference for the hexavalent analogues. On the other hand, the incorporation of additional mannosyl units led merely to statistical binding-affinity enhancements, notably for the less-dense decamer 194, which presents favorable extended intersugar distances. 

Ceriotti has reported a turbidimetric assay using Micrococcus lysodeikticus13. ... 

Kaiser and Camboni reported a turbidimetric assay utilizing Staphylococcus aureus135. 

Kreuzig has described a turbidimetric assay utilizing Streptococcus faecalis. ... 

A turbidimetric assay for potency evaluation of griseofulvin has been reported (38). The drug is dissolved in... 

How would you accomplish the turbidimetric assay of the following medicinal compounds ... 

The main features of the immunological assays for Lp(a) quantification are summarized in Table 5. RIA and ELISA assays are among the most sensitive, while RID and EIA are less sensitive and less suited to the measurement of low Lp(a) levels. The reference values reported for Lp(a) are lowest with the EIA techniques and highest with the turbidimetric assays (R15). 

Bioassay may also be of low-precision design (multiple samples on large plates, i.e., >3 manual turbidimetric assays, small-plate assays). These types of assay are useful for trace analyses (cleaning validation), and are often used for the analysis of samples in body fluids as they are capable of dealing with the large numbers of samples that may be generated in these studies. 

Food and Drug Administration (FDA) replaced the above mentioned method, " Microbiological agar diffusion assay ", with a microbiological turbidimetric assay because the modified method are more accurate and reliable than agar diffusion assay (43). 

The analytical performance of nephelometric or turbidimetric assays can be significantly improved by increasing the reaction rate by addition of water-soluble linear polymers. This allows the use of much lower reactant concentrations and results in a more stable immune complex suspension. 

Nephelometric methods in general are more sensitive than turbidimetric assays and have an average lower limit of detection of 0.1 to 10 mg/L for a serum protein. Lower detection limits are obtained in fluids, such as cerebrospinal fluid and urine, because of their lower lipid and protein concentrations, which results in a better signal-to-noise ratio. In addition, for low molecular weight proteins (e.g., myoglobin, MW 17,800), assay detection Emits can be lowered using a latex-enhanced procedure based on antibody-coated latex beads. ... 

Thakkar H, Cornelius J, Dronfield DM, Medcalf EA, Newman DJ, Price CP. Development of a rapid latex enhanced turbidimetric assay for retinol binding protein. Ann Clin Biochem 1991 28 407-11. 

Medcalf E, Newman DJ, Gorman EG. Rapid latex-enhanced turbidimetric assay for urine albumin. Ann ChnBiochem 1988 25 (Suppl) 1645-55. 

As with turbidimetric assays, many of the direct UV absorbance assays are set up to determine kinetic solubility. However, the UV absorbance method also lends itself well to thermodynamic solubility determination by extending the period of sample agitation prior to filtration to 24 h or more. This offers a number of advantages. The solubility data generated are less dependent on the physical form of the initial material precipitated from DMSO and are much closer to thermodynamic solubility values determined later in discovery and in early development. As such, it gives more consistent solubility data through the discovery phase and enables a better quality early assessment to be made of the likely difficulties or otherwise of progressing a lead series into development. 

Figure 7 Multivalent ligand-induced lectin cross-linking. Multivalent ligands, which are able to simultaneously span two lectin molecules, can form cross-linked aggregates. These aggregates are detectable by spectroscopic means in a turbidimetric assay.

For the determination of potency of tyrothricin the turbidimetric assay method, with Streptococcus faecalis group D) strain M 19 (ATCC 10 541) as test organism, is used. The reference standard is a mixture of 20 per cent crystalline gramicidin and 80 per cent crystalline tyrocidine hydrochloride . ... 

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