Reference

Evaluation of lanthanide-sensitized luminescence spectrometry for the measurement of tetracycline in serum

Evaluation of lanthanide-sensitized luminescence spectrometry for the measurement of tetracycline in serum. Files, Leigh Ann; Hirschy, Linda; Winefordner, J. D. (Dep. Chem., Univ. Florida, Gainesville, FL 32611, USA). J. Pharm. Biomed. Anal., 3(1), 95-100 (English) 1985. CODEN: JPBADA. ISSN: 0731-7085. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) A method is described for the detn. of tetracyclines in blood serum which is based on the formation of an Eu(III)-tetracycline complex, in which the excited tetracycline undergoes intersystem crossing to the triplet state; energy transfer then occurs to the 47-level of the Eu(III) ion. This ion exhibits a narrow emission profile which is much more intense than the broad-band emission of the uncomplexed ligand. The excitation wavelengths for tetracycline [60-54-8], chlortetracycline [57-62-5], and doxycycline [564-25-0] were 398, 395, and 385 nm, resp. and the limits of detection (using an emission wavelength of 617 nm) were 10, 40, and 70 ng/mL, resp. The calibration curves were linear. There was interference between the tetracyclines tested, but this should be no problem, since mixts. of tetracyclines are seldom used. The method offers a simple, rapid, and specific assay.

The effect of citric acid on the availability of tetracyclines in calves

The effect of citric acid on the availability of tetracyclines in calves. Luthman, Jan; Jacobsson, S. O. (Dep. Cattle Sheep Dis., Swed. Univ. Agric. Sci., Uppsala S-750 07, Swed.). Nord. Veterinaermed., 37(1), 22-6 (English) 1985. CODEN: NOVTAV. ISSN: 0029-1579. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Citric acid [77-92-9] did not significantly increase the serum levels of tetracyclines when calves were fed low doses (6-8 mg/kg) of oxytetracycline [79-57-2] and chlortetracycline [57-62-5] in a milk substitute. When the dose of chlortetracycline was increased to 50 mg/kg, addn. of citric acid caused higher serum levels the 1st 2 h after feeding than without citric acid. The ratios of citric acid to drug tested were 5 : 1 and 25 : 1. The palatability of the milk substitute was reduced when large amts. of citric acid was added.