title: Sequential hollow-fiber liquid phase microextraction for the determination of rosiglitazone and metformin hydrochloride (anti-diabetic drugs) in biological fluids.
abstract: A new analytical method for the simultaneous determination of the antidiabetic drugs rosiglitazone (ROS) and metformin hydrochloride (MH) with marked differences in their affinity towards organic solvents (log P of 2.4 and -1.43, respectively) was developed. Prior to the HPLC separation, the drugs were subjected to a sequential hollow fiber liquid phase microextraction (HF-LPME) procedure. Two sequential HF-LPME approaches were considered, the preferred one involves the use of two vials containing solution mixtures for the extraction of ROS (vial 1) and MH (vial 2), respectively, but using the same fiber and acceptor phase. Important parameters that affect the extraction efficiency such as extracting solvent, donor phase conditions, HCl concentration, agitation, extraction time, addition of salt, etc. were studied. Under the optimum conditions, good enrichment factors (EF, 471 and 86.6 for ROS and MH, respectively) were achieved. Calibration curves were linear over the range 1-500 (r(2)=0.998) and 5-2500 ng mL(-1) (r(2)=0.999) for ROS and MH, respectively. The relative standard deviation values (RSD%) for six replicates were below 8.4%. Detection and quantitation limits based on S/N ratio of 3 and 10 were 0.12, 1.0 and 0.36, 3.0 ng mL(-1) for ROS and MH, respectively. The proposed method is simple, sensitive and opens up new opportunities for the microextraction of analytes with contrasting properties.
authors.affiliation: School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
authors.forename: Gazala Mohamed
authors.initials: GM
authors.lastname: Ben-Hander
authors.affiliation: School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia. Electronic address: makahleha@yahoo.com.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Makahleh
authors.affiliation: School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia. Electronic address: bahrud@usm.my.
authors.forename: Bahruddin
authors.initials: B
authors.lastname: Saad
authors.affiliation: School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
authors.forename: Muhammad Idiris
authors.initials: MI
authors.lastname: Saleh
authors.affiliation: School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
authors.forename: Kek Wan
authors.initials: KW
authors.lastname: Cheng
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007004:Hypoglycemic Agents / Q000097:blood / Q000652:urine; D059627:Liquid Phase Microextraction / Q000379:methods*; D008687:Metformin / Q000097:blood* / Q000652:urine*; D000077154:Rosiglitazone; D012997:Solvents / Q000737:chemistry; D045162:Thiazolidinediones / Q000097:blood* / Q000652:urine*
chemical_list: D007004:Hypoglycemic Agents; D012997:Solvents; D045162:Thiazolidinediones; D000077154:Rosiglitazone; D008687:Metformin
keywords: Biological fluids; HPLC–UV; Metformin hydrochloride; Rosiglitazone; Sequential HF-LPME