Microcystin-LR detection based on indirect competitive enzyme-linked immunosorbent assay

Microcystins(MCs)are a group of closely related toxic cyclic heptapeptides produced by common cyanobacte-ria,which cause lots of accidents and threatens human health.In this paper,an indirect competitive enzyme-linked immu-nosorbent assay(ic-ELISA)was established and used to detect microcystin-LR(MC-LR)in drinking and surface waters.The concentration of coating antigen was 5 mg/mL,the dilution of monoclonal antibody MC10E7 was 1:3000,the dilution of enzyme tracer(goat anti-mouse IgG-peroxidase)was 1:3000,the standard concentration of MC-LR ranged from 0.001 mg/L to 30 mg/L,and o-phenylenediamine was used as substrate.The assay showed high relativity with high performance liquid chromatography(HPLC)with a correlation coefficient of more than 99%.The relative standard deviation was less than 10%,the detection limit was achieved down to 0.01 mg/L and up to 5.1 mg/L.The quantitative detection range was from 0.03 mg/L to 3 mg/L,and the antibody had high specificity for[4-arginine]microcystins.It performed well in spite of the influence of the real samples.

Development of ELISA and immunochromatographic assay for ofloxacin

Two rapid, sensitive and reliable immunoassay methods, namely competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) and colloidal gold-based immunochromatographic assay (CGIA), were developed to detect ofloxacin (OFL). The linear range of the CI-ELISA was from 0.5 to 128 ng/mL with a limit of detection (LOD) of 0.35 ng/mL. Good recoveries were obtained in analyzing simulated swine urine samples. The CGIA could accurately estimate OFL at concentrations as low as 10 ng/mL in less than 10 min, and test results were read visually without any instrument.

Effect of Puerarin on the Pharmacokinetics of Baicalin in Gegen Qinlian Decoction (葛根芩连汤) in Mice

Objective： To study the pharmacokinetics of puerarin（PUE） in Gegen Qinlian Decoction（葛根芩连汤, GQD）, and the effects of PUE dosage variations on the pharmacokinetics of baicalin（BAL） in mice. Methods： GQD is composed of the concentrated granules of four Chinese herbs. Three dosages with different levels of PUE, including GQD, GQD co-administered with PUE, and GQD co-administration with two times the amount of PUE, were used to research the pharmacokinetics of PUE and BAL in mice. The indirect competitive enzyme-linked immunosorbent assay（ic ELISA） methods based on an anti PUE-monoclonal antibody（MAb） and BAL-MAb were employed to determine the concentration of PUE and BAL in mice blood. Results： After the co-administration of GQD with PUE, the area under the curves（AUC0-14 h） of PUE increased 2.8 times compared with GQD. At the dose of GQD co-administration at two times that of PUE, the AUC0-14 h of PUE was almost equal to that of GQD co-administration of PUE, showing non-linear pharmacokinetics. The AUC0-48 h of BAL showed a good dose-related increase of PUE（r=0.993） in the range from 100 to 300 mg/kg, indicating that PUE dramatically affects the absorption of BAL in mice. There was no significant difference in the other pharmacokinetic parameters, such as the first time of maximum concentration（Tmax）, the second Tmax, or the mean residence time. Conclusions： The ic ELISA methods were successfully applied to pharmacokinetic studies of PUE and BAL in GQD in mice. The dosage variability of PUE of the main ingredient in GQD affects its own pharmacokinetic characteristics and the absorption characteristics of BAL.