High‐throughput liquid‐chromatography method with fluorescence detection for reciprocal determination of furosemide or norfloxacin in human plasma

Abstract

A simple, high-throughput, highly selective and sensitive HPLC-FLD method for isolation and determination of furosemide and/or norfloxacin in human plasma samples following a simple organic solvent deproteinization step with acetonitrile as sample 'clean-up' procedure is reported. One of the two drug substances plays the internal standard role for the determination of the other. Separation of analyte and internal standard was achieved in less than 5.3 min (injection to injection) on a Chromolith Performance RP-18e column, using an aqueous component containing 0.015 mol/L sodium heptane-sulfonate and 0.2% triethylamine brought to pH = 2.5 with H(3)PO(4). The composition of the mobile phase was: acetonitrile-methanol-aqueous component = 70:15:15 (v/v/v) and the flow-rate was set up to 3 mL/min. The chromatographic method applied to the determination of furosemide relies on fluorescent detection parameters of 235 nm for the excitation wavelength, and 402 nm for the emission wavelength. In case of norfloxacin, the excitation wavelength is set up to 268 nm and the emission wavelength is set up to 445 nm. The overall method leads to quantitation limits of about 27 ng/mL for furosemide, and 19.5 ng/mL for norfloxacin, using an injection volume of 250 microL. The method was applied to the bioequivalence study of two furosemide-containing formulations.

Applications of monolithic columns in liquid chromatography‐based clinical chemistry assays

“…One approach is to use ion-pairing agents. An outline for choosing an ionpairing agent was published to measure the diuretic compounds furosemide and norfloxacin by HPLC with fluorescence detection [31]. This paper shows a need for an ion pairing agent for norfloxacin in human plasma and the effect the ion pairing agent has on the chromatography of both furosemide and norfloxacin [31].…”

“…(100 Â 4.6 mm) [28] Mycophenolic acid, mycophenolic acid glucuronide [24][25][26] Cyclosporin A [27] Busulfan [28] Sirolimus [29] Blood pressure drugs HPLC-fluorescence [30][31][32]34], HPLC-UV [33], HPLC-MS/MS [35] Plasma [30][31][32][33]35], urine [30,34] Chromolith Performance RP-18e (100…”

“…Chromolith (25 Â 4.6 mm) [34], Chromolith SpeedRod RP-18 (50 Â 4.6 mm) [35] Furosemide [30,31], norfloxacin [31] [ 30,31] Sotalol [32] Losartan [33,34], telmisartan [34], valsartan [34] [ 33,34] Verapamil, indiplon [35] Drugs of abuse CEC [36], FIA/HPLC-CID [37], HPLCfluorescence [38,39], HPLC-DAD [40] Urine [36,37,39], plasma [38,39], saliva [39], whole blood [40], solvent [37] Described in text [36], Chromolith Flash RP-18e (25 Â 4.6 mm) [37], Chromolith Performance RP-18e (50 Â 4.6 mm) [38], (100 Â 4.6 mm) [39,40] 3,4-Methylenedioxymethamphetamine, 3,4-methylenedioxyamphetamine, 4-hydroxy-…”

“…An outline for choosing an ionpairing agent was published to measure the diuretic compounds furosemide and norfloxacin by HPLC with fluorescence detection [31]. This paper shows a need for an ion pairing agent for norfloxacin in human plasma and the effect the ion pairing agent has on the chromatography of both furosemide and norfloxacin [31]. An ion-pairing agent with increasing number of carbons shifts the retention time of norfloxacin from about 0.8 min to 1.5-4.25 min [31].…”

Characterization of a new norfloxacin metabolite monitored during a bioequivalence study by means of mass spectrometry and quantum computation

“…Almost all reported methods deal with plasma samples provided from different animals (chickens, pigs; Anadon et al, 1992Anadon et al, , 1995Kowalski et al, 2005), or in poultry tissue (Lim et al, 2002). Recently, a liquid-chromatography method with fluorescence detection was developed, which can be applied to the reciprocal determination of furosemide or norfloxacin in plasma samples, using each of them as internal standard for the determination of the other (Galaon et al, 2007). LC-coupled electrospray and atmospheric pressure chemical ionization technique has been used for the determination of seven quinolones in chicken tissues using norfloxacin as internal standard (Bailac et al, 2006).…”