Comparative study of oxytetracycline and doxycycline on calcium chelation: in-vitro assay

Abstract

Background: Tetracycline class of antibiotics differ in their pharmacokinetic profile and chelating property. Objective of present study is to assess the effect of oxytetracycline and doxycycline on calcium chelationMethods: For estimation of calcium chelation of Oxytetracycline and Doxycycline, EDTA method (P. Trinder) and calcium binding assay was followed. Different doses of Oxytetracycline (25 mg, 50 mg and 100 mg) and Doxycycline (25 mg, 50 mg and 100 mg) were used in EDTA method and different concentrations of calcium were used in calcium binding assay. The procedure was done according to the standard methodology.Results: The intensity of colour appear to be increased with increase in dose of the Oxytetracycline (25 mg, 50 mg, 100 mg) as the concentration of calcium binding increases. But in Doxycycline intensity of colour is more with 100 mg as compared with 25 mg and 50 mg The UV absorption spectrum of solution of Oxytetracycline (1mM) was changed after the addition of CaCl2 to provide different concentration of Ca2+ (0.1, 0.5 and 1.0 mM). With minor shift in the absorption coefficient and no shift in wavelength were observed for Doxycycline.Conclusions: The study concludes that oxytetracycline has more calcium chelating property than doxycycline.