High-performance liquid chromatographic assay to determine midazolam and flumazenil simultaneously in human plasma

Simultaneous determination of midazolam and 1′‐hydroxymidazolam in human plasma by liquid chromatography with tandem mass spectrometry

“…Although LC-UV has been used for decades for the above purpose, these methodologies typically represent relatively poor sensitivity and low throughput, with a reported sensitivity of 1.0-100 ng/mL, sample size of up to 2.0 mL, and analysis cycle time of up to 18 min (Blackett et al, 1988;Carrillo et al, 1998;El Mahjoub and Staub, 2000;Ha et al, 1993;Johnson et al, 2002;Lee and Charles, 1996;Odou et al, 1997;Mastey et al, 1994;Portier et al, 1999;Puglisi et al, 1985;Sautou et al, 1991;ter Horst et al, 2003;van Brandt et al, 1997;Vletter et al, 1990;Yasui-Furukori et al, 2004). GC-MS methods appear to be more sensitive than HPLC-UV with a reported LLOQ of 20 pg/ mL for both midazolam and 1′-hydroxymidazolam when 1 mL of human plasma was used.…”

Plasma concentrations of flumazenil following intranasal administration in children

“…The plasma flumazenil concentrations were determined by a HPLC assay published previously, 10 and was linear at concentrations ranging from 2 to 200 ng·mL -1 . Inter-and intra-day coefficients of variation for accuracy and precision of the flumazenil assay, as measured using quality control samples (2 to 100 ng·mL -1 ), were <4%.…”

“…After induction, 40 µg·kg -1 flumazenil Anexate®, Roche, 0.1 mg·mL -1 (0.4 mL·kg -1 )) were administered via a syringe as drops, prior to nasal intubation. Venous plasma samples were drawn prior to administration of flumazenil (t=0), and then at 2, 4,6,8,10,15, 20, 30, 40, 60, and 120 min thereafter. The plasma samples were immediately processed by the onsite laboratory and then stored at -70°C, before batch analysis via high performance liquid chromatography assay.…”

Determination of midazolam and its major metabolite 1′-hydroxymidazolam by high-performance liquid chromatography-electrospray mass spectrometry in plasma from children

“…For pharmacokinetic studies in such children, the ideal analytical method for MDZ and its metabolites should be one that is sensitive enough to allow use of small quantities of biological fluid (since large sampling volumes are both not acceptable to parents and impractical), and fully selective to avoid interference from concurrently administered drugs (antimalarials, other anticonvulsants, antibiotics, antipyretics/analgesics). Previously published analytical techniques for the determination of MDZ and its metabolites in biological fluids used high-performance liquid chromatography (HPLC) with UV detection [14][15][16][17][18][19][20][21][22][23][24][25], gas chromatography (GC) with electron capture detection [26][27][28], GC-mass spectrometry (MS) [29][30][31] and HPLC-MS with electrospray ionisation [32,33], atmospheric pressure chemical ionisation (APCI) [34][35][36], and fast atomic bombardment (FAB) ionization [37]. These techniques have various limitations, including large sample volumes (1-2 ml) [14][15][16]20,21,23,24,32,35], long retention times [15,17,19], lengthy extraction and derivatisation procedures [30,31], inadequate sensitivity [14][15]…”