Abstract

RAPID DETERMINATION OF AMOXICILLIN LEVELS IN HUMAN PLASMA BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

Reem Alswayeh, Syed N. Alvi, and Muhammad M. Hammami*

ABSTRACT

A simple, precise, and rapid high performance liquid chromatography (HPLC) method for the determination of amoxicillin level in human plasma using nizatidine as an internal standard (IS) was developed and validated. Plasma samples containing amoxicillin were spiked with IS, vertexed for 30 second, and filtered using Millipore centrifree filters. The compounds of interest were efficiently separated on Atlantis 4.6 x 150 mm, dc18, 5-µm column and detected with a photodiode array detector set at 229 nm. The mobile phase, composed of 0.01 M dibasic sodium phosphate buffer (pH 3.5 adjusted with phosphoric acid) and acetonitrile (95:5, v:v), was delivered at a flow rate of 1 ml/min. No interference in blank plasma or of commonly used drugs was observed, and the detection limit of amoxicillin was 0.3 µg/ml. The relationship between amoxicillin concentration in plasma and peak high ratio of amoxicillin /IS was linear (R2 ≥ 0.9986) in the range of 1.0 – 30 µg/ml, intra- and inter-day coefficient of variation and bias were ≤ 3.7% and ≤ 12.0% and ± 9.2% and ± 3.5%, respectively. Mean extraction recovery of amoxicillin and the IS from plasma samples was ≥ 85% and 100%, respectively. The method was used to assess the stability of amoxicillin in human plasma under various clinical laboratory conditions. Further, it was successfully employed to measure amoxicillin level in plasma samples from healthy a volunteer.

Keywords: Amoxicillin, Nizatidine, Human plasma, HPLC.