title: An Eco-Friendly Direct Injection HPLC Method for Methyldopa Determination in Serum by Mixed-Mode Chromatography Using a Single Protein-Coated Column.
abstract: A simple, rapid and environment-friendly direct injection HPLC method for the determination of methyldopa (MTD) in human serum has been developed and validated. The method was based on cleanup and separation of MTD from serum by mixed-mode liquid chromatography using a single protein-coated TSK gel ODS-80 TM analytical column (50 × 4.0 mm i.d., 5 µm). The protein-coated column exhibited excellent resolution, selectivity and functioned in two chromatographic modes: size-exclusion chromatography [i.e., solid-phase extraction (SPE) for serum proteins] and reversed-phase chromatography for the final separation of MTD. SPE and HPLC separation were carried out simultaneously with a green mobile phase consisting of acetate buffer (0.1 M, pH 2.4) at a flow rate of 1 mL/min and at room temperature (23 ± 1°C). The eluent was monitored at emission and excitation wavelengths of 320 and 270 nm, respectively. A calibration curve was linear over the range of 0.1-30 µg/mL with a detection limit of 0.027 µg/mL. This online SPE method was successfully applied to real samples obtained from patients receiving MTD therapy.
authors.affiliation: Pharmaceutical Chemistry Department, Faculty of Pharmacy, Misr International University, Km 28 Ismailia Road, Cairo, Egypt emara_miu@yahoo.com.
authors.forename: Samy
authors.initials: S
authors.lastname: Emara
authors.affiliation: P.I. Lab. Single Cell MS, RIKEN Quantitative Biology Center, 6-2-3, Furuedai, Suita, Osaka 565-0874, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Masujima
authors.affiliation: Pharmaceutical Chemistry Department, Faculty of Pharmacy, Misr International University, Km 28 Ismailia Road, Cairo, Egypt.
authors.forename: Walaa
authors.initials: W
authors.lastname: Zarad
authors.affiliation: Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Modern Sciences and Arts University, 26 July Mehwar Road Intersection With Wahat Road, 6 October City, Egypt.
authors.forename: Maha
authors.initials: M
authors.lastname: Kamal
authors.affiliation: Pharmaceutical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El Aini St., Cairo 11562, Egypt.
authors.forename: Marwa
authors.initials: M
authors.lastname: Fouad
authors.affiliation: Pharmaceutical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El Aini St., Cairo 11562, Egypt.
authors.forename: Ramzia
authors.initials: R
authors.lastname: El-Bagary
mesh_terms: D000328:Adult; D002850:Chromatography, Gel / Q000295:instrumentation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D016014:Linear Models; D008297:Male; D008750:Methyldopa / Q000097:blood*; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods
chemical_list: D008750:Methyldopa