Determination of midazolam in rabbit plasma by GC and LC following nasal and ocular administration

Abstract

GC with nitrogen phosphorus detection and HPLC with UV detection were used to determine midazolam (MDZ) levels in rabbit plasma following ocular and nasal administration. For GC with nitrogen phosphorus detection, the analyte was extracted from the plasma using a three-step liquid-liquid extraction including extraction with an isopropanol/butyl chloride mixture in an alkaline solution, followed by extractions with 1 M HCl, and finally with an alkaline solution of butyl chloride. The recovery of MDZ was dependent on the sample alkalization time prior to the final extraction. The procedure increased the recovery of MDZ up to 99.6%. Improved sample preparation led to a significant increase in the sensitivity of the determination by GC with nitrogen phosphorus detection. The achieved detection limit was 0.34 ng/mL, which is ten times lower than that obtained using HPLC with UV detection. The small plasma volume was another advantage of the GC with nitrogen phosphorus detection method (200 μL per assay). Both administration routes of the anesthetic (nasal and ocular) resulted in comparable plasma MDZ levels. Kinetic simulation of the MDZ plasma was performed for both administration routes.

Comparative pharmacokinetics and bioavailability of intranasal and rectal midazolam formulations relative to buccal administration in rabbits

“…Considering MDZ is not only commonly used in clinic, it is also a well known CYP3A4 substrate that oen used in drugdrug interaction studies, the quantitative determination of MDZ and its major metabolite in bio-matrix is well developed in laboratories worldwide. [16][17][18] Compared with the published analytical methods, the method of our current assessment of midazolam and its metabolite using LC-MS/MS is proved to be both accurate and robust.…”

An Overview on Total Analytical Methods for the Detection of 1,4-Benzodiazepines

“…Both liquidliquid-extraction (LLE) and solid-phase-extraction (SPE) are employed in the blood, oral fluid sample pre-treatment before GC-MS analysis [40]. Midazolam was extracted from the plasma using a three-step liquid-liquid extraction including extraction with an isopropanol/ butyl chloride mixture in an alkaline solution, followed by extractions with 1 M HCl, and finally with an alkaline solution of butyl chloride [41]. SPME and LPME offer relatively new approaches to sample preparation.…”

Plasma concentrations and sedative effects of a dexmedetomidine, midazolam, and butorphanol combination after transnasal administration in healthy rabbits

“…Transnasal (TN) delivery of anesthetics is an emerging practice grounded on good bioavailability and suitable pharmacodynamics; in fact, the TN route is deemed to allow direct delivery of drugs to central nervous system through olfactory and trigeminal nerves with rapid absorption and fast onset of action (Graff & Pollack, 2005;Musulin et al, 2010). Although its efficacy has been demonstrated already in humans and in several animal species (Merkus, 2006;Musulin et al, 2010;Schnellbacher et al, 2012;Hornak et al, 2014), limited information is available on lagomorphs (Robertson & Eberhart, 1994;Jacek et al, 2013;Santangelo et al, 2016). Therefore, here we evaluate in rabbits pharmacokinetics, efficacy and side effects of TN administration of a combination of three different drugs (DMB-TN) that induce sedation and analgesia: dexmedetomidine, a selective a 2 -adrenergic agonist, midazolam, a GABA A receptor allosteric modulator and butorphanol, a j-opioid receptor agonist (Hedenqvist et al, 2002;Chang et al, 2009;Schroeder & Smith, 2011;Bellini et al, 2014).…”