Erythromycin, assay

Exchanges between pharmacopoeias are co-ordinated by the Pharmacopoeial Discussion Group (PDG) (International Harmonisation 1995) and it is frequent that one pharmacopoeia participates in a collaborative study organized by another pharmacopoeia, or that several pharmacopoeias share the same batch of reference substance to be used in their respective monographs nevertheless, in this case the reference substance can not be considered as harmonized. A new batch of erythromycin was shared between the United States Pharmacopoeia and the European Pharmacopoeia and was established in a common coEaborative study both for the microbiological assay (used in the USP for formulations) and the liquid chromatographic assay (used in the Ph. Eur. and USP for bulk material). 

The ultraviolet chemical assay for erythromycin remains largely unchanged from that described by Kuzel et al.9 in 1954. This procedure is essentially as follows. The reference standard, alkali reagent, and buffer solutions are prepared prior to the assay. 

Kavanagh and Dennen20 report microbiological turbidimetric and plate assays for erythromycin base in Analytical Microbiology,... 

Several common methods for the detection of these compounds in environmental media have been proposed such as microbiological assay and conventional chromatographic methods. However, only one example of the application of immunochemical methods to the analysis of environmental samples has been reported [84]. In this case, erythromycin could be measured at concentrations higher than 10 pg L 1 using the Charm II6600/7600 assay in water samples proximal to livestock farms. 

Erythromycin, a macrolide antibiotic, lacks a significant chromophore. Detection sensitivity was enhanced by using a wavelength of 200 nm and selecting an injection solvent of lower conductivity than the BGE. In order to facilitate the separation of erythromycin and its related substances, 35% (v/v) ethanol was incorporated into a 150 mM phosphate buffer pH 7.5. Resolution of all of the compounds was achieved in approximately 45 min. The method was employed as an assay method for erythromycin and for impurity determination. Peptide antibiotics, such as colistin and polymyxin, are mixtures of many closely related compounds. A validated CZE method for impurity analysis of polymyxin B was described, employing 130 mM triethanolamine-phosphate buffer at pH 2.5 to reduce the adsorption of analyte onto the capillary wall. Methyl-/l-cyclodextrin (M-/1-CD) and 2-propanol were found to be necessary for selectivity enhancement. Using similar buffer additives, the same group developed and validated a method for colistin analysis. ... 

Extractions traditionally have been performed using buffers (j ) the same used to obtain the maximum response in standard curves. Unfortunately this has been a major failing of the plate diffusion assay systems. It is rare that the pH can be adjusted to the optimum necessary for greatest response simply by blending a matrix with buffer. As much as a 30 to 40% loss of activity can occur by not adjusting the pH properly analysis for residues of the streptomycins and erythromycin, for example, can yield results 20% lower by having the pH of the analyte 0.2 units below 8.0 if the pH is 0.5 units below 8.0, the loss of potency approaches 50% (14-15). 

The primary application of the procedure is the determination of the presence or absence of 3-lactam 7) residues in milk and secondarily to measure the levels quantitatively. The receptor assay system has now been expanded to qualitatively detect residues of tetracycline, erythromycin, streptomycin, chloramphenicol, novobiocin, and sulfamethazine in milk, serum and urine (Table II) (30). 

Microbiological methods reported for detection of erythromycin in fish are based either on a cylinder plate assay using Sarcina lutea (ATCC 9341) (122),... 

A three-column ion-exchange and reversed-phase system has been developed for the assay of enprostil in soft elastic gelatin capsules [336]. A two-column approach has also been used to resolve D,L-amino acids in complex matrices [337]. Erythromycin A and its known impurities were resolved using two C18 columns [338]. 

Watkins PB, Murray SA, Winkelman LG, et al. Erythromycin breath test as an assay of glucurocorticoid-inducible liver cytochromes P450. J Clin Invest 1989 83 688-697. 

DOTMA E. coli E EBV ECFP ECV EGFP ELISA EYFP FACS FdG FH2 FH4 FK506 FLP propane-aminium-trifluoracetate 7V-[2,3-(dioleyloxy) propyl]-/V,/V,/V-trimethyl ammonium chloride Escherichia coli erythromycine operon/repressor Epstein-Barr virus enhanced cyan fluorescence protein extracellular viral particles enhanced green fluorescence protein enzyme-linked immunosorbent assay enhanced yellow fluorescence protein fluorescence-activated cell sorter fluorescein di- 3-D-galactopyranoside dihydrofolate tetrahydrofolate human immunophilins native recombinase isolated from the 2pm plasmid from Saccharomyces cerevisiae... 

Erythromycin Minimum fill, water, and assay Collapsible tubes or in tight containers at controlled room temperature... 

Erythromycin Minimum fill and assay Tight containers... 

The causative agent in Lyme disease is a spirochetal bacterium (Borrelia burgdorferi) that is transmitted directly through the bite of a deer tick. Optic neittopathy can occur due to Lyme disease and manifests as papillitis, retrobulbar neuropathy, or ischemic optic neiu-opathy. Serologic testing may help to identify Lyme infection by use of indirect immunofluorescent assay and enzyme-linked immunosorbent assay.The treatment of Lyme disease includes oral or intravenous peniciUin, doxycycUne, erythromycin, or ceftriaxone. 

Liquid chromatography-ionspray-mass spectrometry has been shown to be an attractive approach for the determination of semduramicin in chicken liver. Tandem MS using the CID of the molecular ions further enhanced the specificity providing strucmre elucidation and selective detection down to 30 ppb. Liquid chromatography-ionspray-mass spectrometry has also been successfully applied for the assay of 21 sulfonamides in salmon flesh. Coupling of LC with either ISP-MS or ISP-MS-MS has also been investigated as an attractive alternative for the determination of erythromycin A and its metabolites in salmon tissue. The combination of these methods permitted the identification of a number of degradation products and metabolites of erythromycin at the 10-50 ppb level. Tandem MS with CID has also been... 

Mutagenicity assays of bacterial DNA repair in Escherichia coli have been negative with erythromycin. 

The ultraviolet analysis for erythromycin estolate is basically that described by Kuzel e t a 1. 5 Alkali, buffer, and reference standard solutions must be prepared prior to assaying. 

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