Determination of strontium in rat plasma and plasma ultrafiltrate by Zeeman Furnace atomic absorption spectroscopy and its application to a pharmacokinetic study

Abstract

A rapid and sensitive analytical assay for the determination of total strontium concentrations in rat plasma was developed and validated. The total strontium levels were determined by use of graphitefurnace atomic-absorption spectrometry (GF-AAS) with Zeeman correction, 1000°Ci n ashing temperatures and 2700°C in atomization temperatures after 3.5% HNO₃ protein precipitation. The accuracy was between 95.46 and 102.24% (intra-day variation), and 101.74 and 102.15% (inter-day variation). The precision was between 1.86 and 8.24% (intra-day variation), and 1.27 and 11.20% (interday variation). Linear calibration curves were obtained over the concentration range 0.2 to 10 μg/ml(r = 0.9993). Validation data were within the acceptable limits for analytical methods. This assay was successfully applied to evaluate the pharmacokinetics of strontium fructose 1, 6-diphosphate (Sr-FDP), a new compound in rats and free strontium after plasma ultrafiltrate was also performed by direct determination. Significantly different pharmacokinetics between total and free strontium were observed that provided more information for the pharmacokinetic study of Sr-FDP.

Key words: Graphite furnace atomic-absorption spectrometry (GFAAS), strontium fructose 1, 6-diphosphate, strontium, ultrafiltrate, anti-osteoporosis.