Glucuronides immunoassay

The development of class-selective antibodies is another approach to multi-analyte analysis. The analyst may design haptens that will generate antibodies that recognize an epitope common to several compounds, as explained above for the analysis of pyrethroids by measuring PBA. Other examples of class-selective immunoassays that have been developed are mercapturates," glucuronides, pyrethroids, organophosphate insecticides, and benzoylphenylurea insecticides." ... 

Homogeneous TR-FIAs have been reported in which proprietary lanthanide chelates are used. In a homogeneous immunoassay for T4, a fluorescent europium chelate coupled to thyroxine is quenched by antibody binding. 90 A similar approach is used for estrone-3-glucuronide. 91 TRFIAs based on homogeneous methods have not yet become widely used. 

An indirect enzyme immunoassay suitable for the determination of chloramphenicol and its glucuronide was developed for the analysis of urine, milk, tissue, and eggs as well (48). In this assay, chloramphenicol succinate was coupled to both bovine serum albumin and horseradish peroxidase by a mixed anhydride procedure. Unlike tissue and egg samples, urine and defatted milk could be directly analyzed, but when an ethyl acetate extraction was employed in milk analysis, the limit of detection was lowered at least 10 times. 

Coumarins also have a C6-C3 skeleton, but they possess an oxygen heterocycle as part of the C3-unit. There are numerous coumarins, many of which play a role in disease and pest resistance, as well as UV-tolerance. The coumarin umbelliferone (1.21) is popular in enzyme assays. Umbelliferone esters can be used as a substrate for non-specific esterase enzyme assays and in fluorescent immunoassays (Jacks and Kircher, 1967). In order to quantify the enzyme activity of the popular reporter gene P-glucuronidase (GUS), plant extracts can be incubated with 4-methylumbelliferyl P-D-glucuronide (4-MUG 1.22), which upon hydrolysis... 

Staimer, N., Gee, S.J., and Hammock, B.D., Development of a class-selective enzyme immunoassay for urinary phenolic glucuronides, Anal. Chim. Acta, 441, 27-36, 2001. 

Opioids in hair are readily detected with a variety of commercial opioid immunoassays including RIA, FPIA, and Emit. Most opioid immunoassays are formulated to detect morphine and morphine glucuronide, but also exhibit significant cross... 

Wernly et al. (1993) reported also an attempt to use MEKC, without hydrolysis, to determine morphine-3-glucuronide, the major metabolite of morphine (and heroin) in urine. The sensitivity limit (about 1 /ug/mL after solid-phase extraction and concentration) was unsatisfactory for confirmation of the results of the usual enzyme immunoassays, but improvements were deemed to be achievable. 

HPLC with immunoassay detection is useful for the analysis of those metabolites which are difficult to isolate from biological fluids by extraction (e.g. glucuronides). Such polar compounds cannot be observed at low concentrations with conventional detectors as they are obscured by endogenous compounds. HPLC with immunoassay detection can be applied to the determination of cannabin-oids, opiates, lysergide, and cardiac glycosides in biological fluids (A. C. Mof at,Analyl. Proc., 1981, IS, 115-116). 

Immunoassay. THC is extensively metabolized to a large number of compounds, most of which are inactive. The principal urinary metabolite is U -nor-A -tetrahydro-cannabinol-9" carboxylic acid (THC-COOH) and its glucuronide conjugate (see Figure 34-30). Immunoassays designed to screen urine samples for marijuana use measure this and other THC metabolites. These assays are calibrated with THC-COOH, but because of cross-reactivity with many other THC metabolites, quantitative results based on them are 1.5 to 8 times greater than the actual concentration of THC-COOH as determined by GC-MS. Therefore... 

O Connor KA, Brindle E, Hohnan DJ> Klein NA, Soules MR, Campbell KL, et al. Urinary estrone conjugate and pregnanediol 3-glucuronide enzyme immunoassays for population research. Clin Chem 2003 49 1139-48. 

Chemiluminescence-labelling has been applied to the immunoassay of oestriol 16a-glucuronide by synthesis of the A-aminobutyl-A-ethylisoluminol derivative (30), which emits light when oxidized with H202-microperoxidase. Binding of the conjugate (30) to an antibody for the steroid enhances light emission. Competitive... 

K8. Kim, J. B., Kwon, O. J., and Barnard, G., A novel homogeneous immunoassay for estrone-3-glucuronide based on antibody protected effects on the enhancement of chemiluminescence by NaOH. In Bioluminescence and Chemiluminescence Current Status (P. E. Stanley and... 

Dillon R. R, Daly S. J., Manning B. M., and O Kennedy R., Immunoassay for the determination of morphine-3-glucuronide using a surface plasmon resonance-based biosensor, Biosens. Bioelectron., 18, 217-227, 2003. 

The 3-p-glucuronide of 18(3-glycyrrhetic acid has been prepared as an immunogen for enzyme immunoassay, and the selective synthesis of the 3-0-/3-D-glucopyranoside of 20(5)-protopanoxadiol (ginsenoside) from selectivity protected 12-0-acetyldamnar-24-en-3p,12 3,20(5)-triol has been described. ... 

DiUon, P., Manning, B., Daly, S., KiUard, T., O Kemedy, R., 2003. Production of recombinant anti-morphine-3-glucuronide single-chain vanahle fragments (scFv) antibody for the development of a real-time biosensor-based immunoassay. J. Immunol. Methods 276, 151—161. 

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