Development of a High-Performance Liquid Chromatographic Method for Determination of Letrozole in Wistar Rat Serum and its Application in Pharmacokinetic Studies

Abstract

A fast, sensitive, and specific reversed-phase high-performance liquid chromatographic (RP–HPLC) method for the determination of letrozole in Wistar rat serum was developed. In this method, liquid–liquid extraction of letrozole was achieved using diethyl ether as the extracting solvent. The analysis was carried out on a reversed-phase C18 (250 mm × 4.6 mm, 5 μm) column with an isocratic mobile phase of methanol–water (70:30,v/v), at a flow rate of 1.0 mL min−1. Detection was carried out at 239 nm with a UV–visible spectrophoto-metric detector. The method was shown to be selective and linear over the concentration range of 0.15–100 μg mL−1. The intra-day and inter-day precision studies showed good reproducibility with coefficients of variation less than 11% for the analyte. The relative errors of intra– and inter–day accuracy were within −11.52 to −2.26%. The limit of quantification was evaluated to be 0.15 μg mL−1. The method was successfully applied for the pharmacokinetic study of letrozole after oral administration of 10 mg kg−1 of letrozole in six healthy Wistar rats.

SPE–UPLC–MS/MS assay for determination of letrozole in human plasma and its application to bioequivalence study in healthy postmenopausal Indian women

“…However, this technique did not provide cleaner extracts which were apparent from strong matrix interferences and poor recovery especially at LLOQ and LQC concentration levels. A similar observation was also reported in a previous study [12] . Further, LLE was tested using methyl tert-butyl ether, dichloromethane, n -hexane and ethyl acetate as single solvents and also as binary mixtures in different proportions.…”

“…To establish a linear concentration range from 0.1 to 100 ng/mL, it was essential to optimize an efficient extraction protocol to obtain quantitative and precise recovery of LTZ and LTZ-d4 with minimal matrix effect. As all three conventional extraction methodologies, namely protein precipitation (PP) [8] , [10] , liquid-liquid extraction (LLE) [7] , [12] and SPE [6] , [9] , [11] , have been used previously, a systematic study was undertaken to optimize the best extraction conditions with all three approaches. As the PP has the advantage of simplicity and speed of analysis, the initial attempts were done with methanol and acetonitrile as protein precipitants.…”

“…Several methods are reported for the determination of LTZ as a single analyte [3] , [4] , [5] , [6] , [7] , [8] , [9] , [10] , [11] , [12] , together with its inactive metabolites [13] , [14] and with other drugs like tamoxifen and anastrozole [15] in different biological matrices. Mainly liquid chromatography with UV [4] , [5] , [12] , fluorescence [3] , [14] or mass spectrometry [6] , [7] , [8] , [9] , [10] , [11] , [13] , [15] detection has been used for the quantification of LTZ in various matrices like human urine, rat plasma and human plasma. All previous methods based on liquid chromatography with mass spectrometric detection have sensitivity less than 0.2 ng/mL and chromatographic analysis time ranging from 3.0 to 16.0 min.…”

A simple, precise, and sensitive HPLC method for quantification of letrozole in rat plasma: development, validation, and preclinical pharmacokinetics

“…LTZ is approved for oral hormonal therapy by the USFDA and is sold under the brand name Femara® to treat local or metastatic breast cancer in post-menopausal women. LTZ undergoes complete absorption from the gastrointestinal tract and metabolizes to form the carbinol metabolite, which is inactive and further excreted in the urine (Acharjya et al 2012) Several analytical techniques such as UV spectrophotometry, liquid chromatography, gas chromatography, and mass spectrophotometry have been reported for the estimation of LTZ either alone or in combination (Berzas et al 2003;Mareck et al 2005;Mondal et al 2007;Laha et al 2008). In this regard, we have previously reported a sensitive, robust, and stable analytical liquid chromatographic (RP-HPLC) method to estimate LTZ in bulk and in nanoformulations (Hegde et al 2018).…”

Quantitative and qualitative analysis of the novel antitumor 1,3,4-oxadiazole derivative (GLB) and its metabolites using HPLC-UV and UPLC-QTOF-MS

“…During the research and development of anticancer agent GLB, the pharmacokinetic profile is needed for understanding the absorption, distribution, metabolism and excretion (ADME) of GLB in vivo 22 . The high performance liquid chromatographic - ultraviolet detector (HPLC-UV) is a conventional quantitative analysis method 23 24 25 26 . In according to the ultraviolet absorption wavelength, elution retention time and chromatographic peak area, the content of compound can be accurately measured 27 28 29 30 .…”