ENVIRONMENTAL-ANALYSIS IN THE WORKPLACE - DEVELOPMENT OF AIRBORNE MONITORING SYSTEMS FOR POTENTIALLY HARMFUL PHARMACEUTICALS - AN IMPROVED RAPID ELISA FOR CEFTAZIDIME

Ceftazidime is a beta-lactam antibiotic of the cephalosporin family. I n common with other beta-lactam antibiotics it is a respiratory sensit iser and occupational exposure limits have been set for workers who ma y inhale the drug in the workplace. Polyclonal antibodies have been ra ised in rabbits which specifically recognise this compound. These have been purified using immunoaffinity chromatography and the resulting a nti-drug antibodies used with alkaline-phosphatase labelled anti-rabbi t antibodies to generate a single reagent ELISA for ceftazidime which can be used in a rapid semi-quantitative mode to screen samples from c onventional filters following monitoring of worker exposure. Presence of the drug in excess of the occupational exposure limit (GEL) (3 mu g of captured ceftazidime eluted into 1 ml prior to assay) results in a lack of colour at the endpoint of the assay while samples with levels less than the OEL produce a yellow colour. The ELISA can process 45 s amples in duplicate in 40 min. The sensitivity of the assay is 110 pg in a 50 mu l sample volume. The assay has good precision with coeffici ents of variation less than 10% and it exhibits insignificant interfer ence with a range of penicillin and cephalosporin antibiotics and othe r compounds tested. The assay is better suited than liquid chromatogra phy for use on site by semi-skilled operatives immediately following t he monitoring period when exposure of workers above the OEL can be rap idly ascertained and action taken.