Development and Validation of a Spectrofluorimetric Method for the Assay of Tetracycline in Capsules

Abstract

The purpose of this study is to develop and validate a method for the analysis of tetracycline capsules by spectrofluorimetry. A pH 9 borate buffer was used as diluent of tetracycline after reaction with magnesium salt at the excitation wavelength of 372 nm and 516 nm of emission. A linear response was observed between 0.25 μg/mL and 1.5 μg/mL with a correlation coefficient (R) of 0.9998. The detection and quantification limits found are 0.0125 μg/mL and 0.0412 μg/mL respectively. The proposed method proved trueness with a recovery between 99.88% and 101.10%. The relative standard deviations of repeatability and intermediate precision found ≤2.88% reflected a good precision of the method. The proposed method is therefore valid within the limits of 90% to 110%. The proposed method was applied to the quality control of 9 tetracycline samples from market and gave results in accordance with the pharmacopoeia standards.