A high performance liquid chromatography (HPLC) assay, a radioimmunoassay (RIA), an enzyme immunoassay (EMIT) and a fluorescence immunoassay (FIA) method for assaying serum gentamicin were compared in terms of accuracy and precision. Spiked human serum samples in the range of 0-11.6 mg.1(-1) gentamicin were used in all the tests. Regression analysis and analysis of variance were performed. The Performance Index (PI) was used to qualify the different methods. Other aspects of performance were also compared: simplicity, speed, cost, application in relation to workload. After extensive statistical evaluation the FIA method gives the best results.

A case of a serious poisoning with the calcium entry blocker amlodipine is described, which was treated effectively with 4-aminopyridine. Calcium is suggested as general treatment of poisoning with calcium entry blockers in many guidelines. The use of intravenous 4-aminopyridine is theoretically useful to treat poisoning from calcium entry blockers and was demonstrated in this case report.

Three specific immunological methods for the determination of netilmicin and two enzyme immunoassays for gentamicin were compared for assaying serum netilmicin. The commercial kits we used were Radioimmunoassay (RIA), Substrate Labelled Fluorescence Immunoassay (gentamicin) ( SLFIA ), Homogeneous Enzyme Immunoassay (gentamicin and netilmicin) (EMIT) and Fluorescence Polarization Immunoassay ( FPIA ). After analysing spiked calf serum samples in the range of 0-15.8 mg X 1(-1) netilmicin, extensive statistical analysis was performed. The Performance Index was used to qualify the different methods. Results show that the SLFIA (gentamicin) kit is a very acceptable method for the determination of serum netilmicin levels, well comparable with the EMIT (gentamicin) kit and the EMIT (netilmicin) kit. FPIA and RIA require expensive specialized apparatus so it is only economically feasible when other drugs or substances are also determined on the same apparatus. The abilities and specific needs of each laboratory will play an important role in the choice of a method, because the tested kits are all within the range we need from a clinical point of view.

Atracurium is a novel his-quaternary (x~mpetitive neuromuscular blocking agent. The drug was designed to undergo lapid chemical inactivation by "Rofmann elimination" at physiological pH and temperature to form laudancsine. Beside hydrolysis, atracurium is metabollzed to a quaternary alcohol and acid and metholaudanosine, which all breakdown to laudanosine. ( I ) It is known that laudanosine can induce oonvulslons. We developed a method for the determination of atracuri~m and laudano6ine in one run: I ml serum, 50 ~I sulphuric acid I M, 0.1 ml internal standard (hexafluorenium bromide I0 mg 1 -I ) and 0.1 ml potassium iodide solution (50 g 1 -j) are mixed; 7.0 ml DCM was added and 50 ~i is injected into the HPLC. Eluens: acetonitrile + sodium sulphate 0.03 M = 25 + 75, + sulphuric acid I M to pa 3.5 ; column 150 x 4.6 ram, Nucleosil 5C18; detection LrV at 210 nm, and fluorescence Em.320 nm, Exc. 280 urn. Sensitivity in spiked calf's serum: atracurium 25 ~g.l -I and lau~anosine 5 ~g.l -I . With this method and with the more time consuming assay of Neill and Jones (2) (unlike their publication), we al~ys found two peaks from the pure su~stanoe atracurium. ~ two did not correspond with the known degradation p rgducts. By TiC we could confirm our findings. In Tracrium~ ampoules (atracurium for h~an i.v. injection) we found with our method atracurium and three degradation pLod.,cts.