A Reliable Method to Quantify Sildenafil and its Metabolite N-Demethylsildenafil by HPLC in Plasma of Children

Abstract

The aim of this study was to develop a simple method for quantifying plasma levels of sildenafil and its metabolite by liquid chromatography with a C18 reverse-phase column and UV detection. For both compounds, linearity was assessed in the range from 10 and 1 000 ng · ml⁻¹ and had correlation coefficients of r=0.995 and r=0.997 for sildenafil and its metabolite, respectively. The inter- and intra-day coefficients of variation was<5.3%. The limits of detection and quantification were 1 and 10 ng · ml⁻¹. Drug levels were determined satisfactorily in two patients. A simple and reliable method was developed for use in children with Pulmonary Arterial Hypertension under treatment with sildenafil.

Key words

children - liquid chromatography - sildenafil - pharmacokinetics - plasma levels

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