HPLC determination of diltiazem in human plasma and its application to pharmacokinetics in humans

Abstract

A simple and sensitive reversed-phase high performance liquid chromatographic method (HPLC) has been developed and validated for the routine analysis of diltiazem in human plasma and the study of the pharmacokinetics of the drug in the human body. Diltiazem and diazepa (internal standard) were extracted with a mixed organic solution of hexane, chloroform and isopropanol (60:40:5, v/v/v), and then HPLC separation of the drugs was performed on an Spherisorb C(18) column and detected by ultraviolet absorbance at 239 nm. The use of methanol-water solution (containing 2.8 mm triethylamine, 80:20, v/v) as the mobile phase at a fl ow-rate of 1.2 mL/min enables the baseline separation of the drugs free from interferences with isocratic elution. The method was linear in the clinical range 0-300 ng/mL and the lower limit of detection of diltiazem in plasma was 3 ng/mL. The range of percentage of relative standard deviation (%RSD) was from 3.5 to 6.8% for within-day analyses and from 6.2 to 8.4% for between-day analyses, respectively. The extraction recoveries of diltiazem from spiked human plasma (n = 5) at three concentrations were 91.4-104.0%. The method has been used to determine diltiazem in human plasma samples from eight volunteers who had taken diltiazem hydrochloride slow release tables and the data obtained was fitted with a program on computer to study the pharmacokinetics. The results showed that the peak level in plasma approximately averaged 118.5 +/- 14.3 ng/mL at 3.1 +/- 0.4 h, and the areas under the drug concentration curves (AUC) was 793.1 +/- 83.1 ng.h/mL.

Development and validation of a high throughput and robust LC–MS/MS with electrospray ionization method for simultaneous quantitation of diltiazem and its two metabolites in human plasma: Application to a bioequivalence study

“…Previous methods for the determination of diltiazem in biological fluids were based on GCMS or HPLC-UV [4][5][6][7][8]. Few methods have been reported for the simultaneous determination of diltiazem and its metabolites [9][10][11].…”

Determination of diltiazem based on the reduction of Cu(II)–BCA complexes in micellar medium

“…Potentiometric techniques could be more useful for this purpose but they use either organic solvents 16 or selective electrodes, which must be previously assembled. 18,19 In contrast, chromatographic techniques have been preferentially used for diltiazem determination in biological samples such as human plasma 20,22,24 or urine. 24 It can be also seen from Table 1 that most of the methods presented are based on spectrophotometric analysis, probably because of its simplicity, low cost, and the roughness of the spectrophotometric technique.…”

Nonlinear calibrations on the assay of dilitiazem and two of its metabolites from plasma samples by means of liquid chromatography and ESI/MS2 detection: application to a bioequivalence study

“…Most of the reports refering to the assay of diltiazem and its metabolites in plasma samples are based on HPLC separation and UV spectrometric detection, using two different methods for sample preparation in order to enhance on the sensitivity of measurements: liquid-liquid extraction (LLE; Parissi-Poulou et al, 1990;Carignan et al, 1995;Paczkowski et al, 1995;Scully et al, 1996;Li et al, 2003) and solid-phase extraction (SPE) (Ascole et al, 1994;Molden et al, 2002;Zendelovska et al, 2003). Two recent works reported analytical methods based on HPLC and mass spectrometry (MS) for determination of diltiazem and several metabolites in human plasma.…”