Simultaneous determination of nitrendipine and hydrochlorothiazide in spontaneously hypertensive rat plasma using HPLC with on-line solid-phase extraction

A HPLC method with on-line solid phase extraction (SPE) and DAD detection was developed for the simultaneous determination of nitrendipine and hydrochlorothiazide in spontaneously hypertensive rat (SHR) plasma. Plasma samples (100 μL) were injected directly onto a CAPCELL MF C8 SPE column. High-abundance proteins and most matrixes in plasma were removed by on-line SPE technology, while nitrendipine and hydrochlorothiazide trapped on the SPE column were effectively separated on a C18 analytical column. The column temperature was maintained at 20 °C. The optimal detection wavelength was 237 nm for NTDP and 271 nm for HCTZ. The total analytical run time was 34 min. The proposed method was linear over the range 5–500 ng mL−1 for nitrendipine and 10–1000 ng mL−1 for hydrochlorothiazide. The lower limit of detection (LLOD) was 0.5 and 0.6 ng mL−1 for nitrendipine and hydrochlorothiazide, respectively. The sensitivity and precision of the method were within acceptable limits during validation period. The method was successfully used to investigate the pharmacokinetic characteristics of nitrendipine and hydrochlorothiazide in spontaneously hypertensive rats.

► Simultaneous determination of two chemical compounds with different polarity and solubility (NTDP and HCTZ) in SHR plasma using HPLC with on-line solid-phase extraction.
► Many anti-hypertension drugs were lipophilic, and the polarity and solubility was different from HCTZ. So this method may be used for the simultaneous quantification in combination therapy with HCTZ.
► The method is simple, sensitive and reliable.