title: Simultaneous determination of azilsartan and chlorthalidone in rat and human plasma by liquid chromatography-electrospray tandem mass spectrometry.
abstract: Azilsartan medoxomil (AZM), an ester prodrug of azilsartan (AZ), and chlorthalidone (CLT) have recently been approved as a combination therapy for the management of hypertension. This is the first report which described a selective and sensitive method for the simultaneous quantification of AZ and CLT in rat and human plasma using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). AZ and CLT were extracted from plasma by liquid-liquid extraction technique and separated on a C18 reverse phase column using ammonium acetate (10mM, pH 4)-mixture of methanol and acetonitrile (8:92, v/v) as a mobile phase at a flow rate of 0.7mL/min. Detection was performed by electrospray ionization (ESI) operated in negative multiple reaction monitoring (MRM) mode. The lower limit of quantitation (LLOQ) of this method was 1ng/mL and the calibration curves were linear (r(2)≥0.995) over the concentration range of 1-4000ng/mL for both the analytes. The intra- and inter-day precision and accuracy were well within the acceptable limits. The mean extraction recoveries were found to be about 80% and no matrix effect was observed. AZ and CLT were found to be stable under all relevant storage conditions. The method was successfully applied to the oral pharmacokinetic study of AZM and CLT in rats. Further, the sensitivity of the method enabled the determination of protein binding of AZ and CLT in human plasma.
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow 226032 India; Academy of Scientific and Innovative Research, New Delhi 110001 India.
authors.forename: Rachumallu
authors.initials: R
authors.lastname: Ramakrishna
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow 226032 India; Academy of Scientific and Innovative Research, New Delhi 110001 India.
authors.forename: Santosh Kumar
authors.initials: SK
authors.lastname: Puttrevu
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow 226032 India; Academy of Scientific and Innovative Research, New Delhi 110001 India.
authors.forename: Manisha
authors.initials: M
authors.lastname: Bhateria
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226032 India; Academy of Scientific and Innovative Research, New Delhi 110001 India.
authors.forename: Veenu
authors.initials: V
authors.lastname: Bala
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226032 India.
authors.forename: Vishnu L
authors.initials: VL
authors.lastname: Sharma
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow 226032 India; Academy of Scientific and Innovative Research, New Delhi 110001 India. Electronic address: rabi_bhatta@cdri.res.in.
authors.forename: Rabi Sankar
authors.initials: RS
authors.lastname: Bhatta
mesh_terms: D000818:Animals; D001562:Benzimidazoles / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D002752:Chlorthalidone / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D016014:Linear Models; D008297:Male; D010069:Oxadiazoles / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D011485:Protein Binding; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D001562:Benzimidazoles; D010069:Oxadiazoles; C521273:azilsartan; D002752:Chlorthalidone
keywords: Azilsartan; Azilsartan medoxomil; Chlorthalidone; LC-MS/MS; Pharmacokinetics; Protein binding