Development and application of a radioimmunoassay for tetracycline.

Antiserum against tetracycline was produced in rabbits immunized with a tetracycline hapten conjugated to bovine serum albumin. The antiserum was used to develop a radioimmunoassay for tetracycline. As little was 1 ng of tetracycline can be detected in one sample. The antitetracycline antiserum showed a considerable degree of specificity since it cross-reacted only with chlortetracycline (70%). However, its cross-reactivity with oxytetracycline, doxycycline, demeclocycline, methacycline and rolitetracycline was only negligible. The radioimmunoassay of tetracycline was used to measure the systemic bioavailability of orally administered tetracycline (25 mg/kg) to a group of mongrel dogs. Detectable levels of tetracycline were exhibited within 30 min and maximum plasma concentrations of the drug occurred within 3 to 4 hr after dose administration.