SYNTHESIS OF CONJUGATES FOR A BARBITURATE SCREENING ASSAY

Novel derivatives of barbiturates functionalized with free carboxylic acids were designed and synthesized. Coupling of 5-cyclopentyl-5-carbo xycrotylbarbituric acid via its active ester to an aminofluorescein de rivative produced a fluorescent tracer. Conjugation of the 5-cyclopent enyl-5-carboxyethylbarbituric acid via its mixed anhydride to thyroglo bulin allowed for subsequent development of a polyclonal antibody whic h was evaluated for binding in a fluorescence polarization immunoassay format with various barbiturates. The binding studies showed good cro ss-reactivity of a variety of barbiturates containing both aromatic an d aliphatic 5-substituents with the tested antisera. The relationship between the immunogen architecture, the chemical structure of the bind ing analytes, and the characteristics of the antisera is also presente d.