Background: Conivaptan inhibits two of vasopressin receptor (vasopressin receptor V1a and
V2). Conivaptan is used for the treatment of hyponatremia, and in some instances, for the treatment of
the heart failure.
Methods: The present study aimed to develop a simple, sensitive, and accurate HPLC with ultraviolet
detection for the assay of conivaptan (CON) in mouse plasma using bisoprolol as internal standard (IS).
A precipitation procedure was used to extract CON and the IS from the mouse plasma. CON was chromatographically
separated using a C18 analytical column at 25°C. The separation was carried out using
a mixture of phosphate buffer (50 mM): acetonitrile (60: 40, v/v, pH 4.5) with a flow rate of 1.0 ml/min
and detection was performed at 240 nm.
Results: The assay was validated according to the US Food and Drug (FDA) guidelines. The method
demonstrated linearity over a concentration range of 150 - 2000 ng/ml (correlation coefficient: r 2 =
0.9985). The mean recovery of CON from the mouse plasma was 101.13%. All validation parameters
for CON were within the acceptable range.
Conclusion: The investigated method has been shown to be suitable for estimating the CON in plasma
samples, and this method is sensitive and highly selective, allowing the estimation of its concentrations
up to the nano-scale. The suggested method was successfully used in a pharmacokinetic study of CON
in mouse plasma.