Glycated hemoglobin A1c level on the day of emergency surgery is a marker of premorbid glycemic control: a retrospective observational study

Sugammadex, a γ-cyclodextrin derivative, belongs to a new class of selective relaxant binding agents. Sugammadex was approved 10-years ago by the European medicines agency and today is used in clinical anesthesia and emergency medicine globally. In this review, indications for neuromuscular block, the challenge of neuromuscular monitoring and the practice of under-dosing of sugammadex as a potential cost-saving strategy are discussed. Reversal of neuromuscular block is important to accelerate the spontaneous recovery of neuromuscular function. Sugammadex is able to reverse a rocuronium- or vecuronium-induced neuromuscular block rapidly and efficiently from every depth of neuromuscular block. However, since sugammadex was introduced in clinical anesthesia, several studies have reported administration of a lower-than-recommended dose of sugammadex. The decision to under-dose sugammadex is often motivated by cost reduction concerns, as the price of sugammadex is much higher than that of neostigmine outside the United States. However, under-dosing of sugammadex leads to an increased risk of recurrence of neuromuscular block after an initial successful (but transient) reversal. Similarly, when not using objective neuromuscular monitoring, under-dosing of sugammadex may result in residual neuromuscular block in the postoperative care unit, with its attendant negative pulmonary outcomes. Therefore, an appropriate dose of sugammadex, based on objective determination of the depth of neuromuscular block, should be administered to avoid residual or recurrent neuromuscular block and attendant postoperative complications. Whether the reduction in perioperative recovery time of the patient can be translated into additional procedural cases performed, faster operative turnover times, or improved organizational resource utilization, has yet to be determined in actual clinical practice that includes verification of neuromuscular recovery prior to tracheal extubation. The current review addresses the indications for neuromuscular block, the challenge of neuromuscular monitoring, the practice of under-dosing of sugammadex as a potential cost-saving strategy in reversal of deep neuromuscular block, the economics of sugammadex administration and the potential healthcare cost-saving strategies.     

Effects of sugammadex on immunoreactivity of calcineurin in rat testes cells after neuromuscular block: a pilot study

Reversal of neuromuscular blockage induced by steroidal neuromuscular blocking agents such as rocuronium can be achieved using normal dose of sugammadex, which has been shown to be very effective for such reversal. In this study, we determined the effects of sugammadex on calcineurin immunoreactivity by examining the histopathological and histochemical structure of rat testis cells after neuromuscular blockage. Moreover, the regional distribution levels of calcineurin immunopositive testes cells were investigated. Eighteen adult male, Sprague–Dawley rats were divided into one control and two study groups. Study groups 1 and 2 rats received sugammadex at doses of 16 and 96 mg kg⁻¹ i.v., respectively, after rocuronium treatment (mg kg⁻¹ i.v.). The control group received intravenous 0.9% NaCl 1 ml. i.v without any drug. Our study demonstrates that sugammadex is safe and effective for reversal of rocuronium effects in rats, as well as in other animals and humans. Furthermore, histopathological examination indicates that high levels of sugammadex–rocuronium complexes accumulate a little in testis tissue. We found that rocuronium-sugammadex complexes were remained in circulation for a long time resulting in a decrease in interstitial space, testis size, germ cell numbers and Leydig cell numbers. Calcineurin immunoreactivity was higher in the experimental groups than the control group due to increase of calcium level. The results suggest that sugammadex–rocuronium complexes are cause histopathological and immunohistochemical changes in testis interstitial tissues, as well as changes in sperm density and germ cell number.     

Preferences of Mexican anesthesiologists for vecuronium, rocuronium, or other neuromuscular blocking agents: a survey

Background  

Several neuromuscular blocking (NMB) agents are available for clinical use in anesthesia. The present study was performed in order to identify preferences and behaviors of anesthesiologists for using vecuronium, rocuronium or other NMB agents in their clinical practice.     

Gas chromatographic–mass spectrometric assay for rocuronium with potential for quantifying its metabolite, 17-desacetylrocuronium, in human plasma

A rapid, sensitive and selective method has been developed for the quantification of plasma concentrations of neuromuscular blocking drug, rocuronium, using gas chromatography with mass spectrometric detection. 3-Desacetylvecuronium served as the internal standard. The method involved iodide ion pair formation and a single-step liquid–liquid extraction with dicholoromethane. This method also permits simultaneous determination of its putative metabolite, 17-desacetylrocuronium, although the high detection limit for the metabolite limits the practical application of this method in pharmacokinetic study of the metabolite. The extraction efficiency was 75% for rocuronium and 50% for 17-desacetylrocuronium. The limit of quantification was 26 ng/ml for rocuronium and 870 ng/ml for its metabolite. The assay was used successfully in a patient undergoing liver transplantation and receiving rocuronium as a constant rate infusion and in a patient undergoing general elective surgery receiving the drug as an intravenous bolus. This assay is a time-saving alternative to published gas or liquid chromatographic methods for assaying rocuronium.     

Screening procedure for eight quaternary nitrogen muscle relaxants in blood by high-performance liquid chromatography-electrospray ionization mass spectrometry

A screening procedure was developed for the identification and the quantification of eight quaternary nitrogen muscle relaxants, including d-tubocurarine, alcuronium, pancuronium, vecuronium, atracurium, mivacurium, rocuronium and mebezonium, in blood samples. The procedure involves ion-pair extraction with methylene chloride at pH 5.4, reversed-phase HPLC separation and electrospray ionization mass spectrometry detection. The procedure was validated in terms of linearity (0.9295 for all the target compounds at 0.1 mg/l). The screening test was found satisfactory and applied in two fatal deaths. In the first case, toxicological investigations on biological fluids collected during the autopsy revealed the presence of vecuronium (1.2 and 0.6 mg/l in blood and urine, respectively) and its desacetylated metabolite, 3-hydroxy-vecuronium (4.4 and 0.7 mg vecuronium equivalent/l in blood and urine, respectively). In the second forensic case, blood analysis showed high levels of mebezonium (6.5 mg/l). The developed procedure was found suitable for forensic investigations.     

Highly sensitive method for the determination of tamsulosin hydrochloride in human plasma dialysate, plasma and urine by high-performance liquid chromatography–electrospray tandem mass spectrometry

A highly sensitive method for the determination of tamsulosin hydrochloride, a structurally new type of sulphamoile derivative, in human plasma dialysate, plasma and urine has been developed by using liquid chromatography–electrospray tandem mass spectrometry (LC–MS–MS). Plasma dialysate, plasma and urine samples were extracted by brief liquid-phase extraction and analyzed using an HPLC system coupled to a mass spectrometer via an electrospray ionization interface. Selected reaction monitoring was used for the detection of tamsulosin and its internal standard. This method was validated in the concentration range 10–1000 pg/ml in plasma dialysate, 0.5–50 ng/ml in plasma, and 1–100 ng/ml in urine with sufficient specificity, accuracy and precision. The in vivo protein binding study demonstrated that the unbound tamsulosin in human plasma obtained by the equilibrium dialysis after 0.4-mg oral dosing was measurable. In addition, the percentage of unbound tamsulosin in an in vitro study (0.71–0.91%) obtained by using spiked ¹⁴C-labelled tamsulosin was slightly larger than that of the in vivo study (0.68–0.86%), indicating that the unbound concentration calculated by the product of the plasma concentration and the in vitro unbound fraction (fu) was unfavorably overestimated. These results suggest that the combination of LC–MS–MS and equilibrium dialysis method has enough sensitivity to determine the unbound concentration in clinical use and gives the concentration more exactly than the in vitro fu.     

Determination of vecuronium in blood by HPLC with UV and electrochemical detection: a pilot study in man.

Vecuronium bromide is a non-depolarizing neuromuscular blocking agent with a rather low therapeutic level. Rapid, sensitive, and selective determination of vecuronium bromide in human blood or plasma was essential for pharmacokinetic study. We developed such a method using HPLC with electrochemical detection. Samples were first acidified, followed by a one-step liquid-liquid extraction. Tubocurarine, which has a structure similar to that of vecuronium, was used as the internal standard. The electrochemical detector, Ag/AgCl electrodes, was operated by setting the working electrodes, W1 and W2, at +0.65 V and +1.05 V, respectively. When vecuronium blood concentration was plotted versus peak area ratios (PAR) of vecuronium over tubocurarine, a linear relationship was observed over the range of 25 ng/mL to 500 ng/mL with a correlation coefficient greater than 0.997. Clinically possible sources of interference, such as atropine, apresoline, droperidol, fentanyl, labetalol, thiopentone, atracurium, and valium, were examined and none showed interference in the assay of vecuronium and tubocurarine. This method has been successfully applied in a preliminary study of the pharmacokinetics of vecuronium in a patient undergoing surgery. The low detection limit of this method in the patient was 3 ng/mL.     

Development and validation of a liquid chromatographic-tandem mass spectrometric method for determination of oseltamivir and its metabolite oseltamivir carboxylate in plasma, saliva and urine

A bioanalytical method for the analysis of oseltamivir (OP) and its metabolite oseltamivir carboxylate (OC) in human plasma, saliva and urine using off-line solid-phase extraction and liquid chromatography coupled to positive tandem mass spectroscopy has been developed and validated. OP and OC were analysed on a ZIC-HILIC column (50 mm x 2.1 mm) using a mobile phase gradient containing acetonitrile-ammonium acetate buffer (pH 3.5; 10mM) at a flow rate of 500 microL/min. The method was validated according to published FDA guidelines and showed excellent performance. The lower limit of quantification for OP was determined to be 1, 1 and 5 ng/mL for plasma, saliva and urine, respectively and for OC was 10, 10 and 30 ng/mL for plasma, saliva and urine, respectively. The upper limit of quantification for OP was determined to be 600, 300 and 1500 ng/mL for plasma, saliva and urine, respectively and for OC was 10,000, 10,000 and 30,000 ng/mL for plasma, saliva and urine, respectively. The within-day and between-day precisions expressed as R.S.D., were lower than 5% at all tested concentrations for all matrices and below 12% at the lower limit of quantification. Validation of over-curve samples ensured that it would be possible with dilution if samples went outside the calibration range. Matrix effects were thoroughly evaluated both graphically and quantitatively. No matrix effects were detected for OP or OC in plasma or saliva. Residues from the urine matrix (most likely salts) caused some ion suppression for both OP and its deuterated internal standard but had no effect on OC or its deuterated internal standard. The suppression did not affect the quantification of OP.     

Dalbavancin: Quantification in human plasma and urine by a new improved high performance liquid chromatography-tandem mass spectrometry method

Dalbavancin is a novel second-generation lipoglycopeptide antibiotic with activity against broad range of Gram-positive pathogens. In order to determine the pharmacokinetics (PK) of dalbavancin in pediatric patients, a new High Performance Liquid Chromatography-Tandem Mass Spectrometry (HPLC-MS/MS) bioanalytical method has been developed for quantification of dalbavancin in plasma and in urine. The plasma method was validated for dalbavancin in the linear range from 0.5 μg/mL to 500 μg/mL using 50 μL of K(2) EDTA plasma. For dalbavancin spiked in urine, non-specific binding (NSB) of the drug to polypropylene (PP) urine collection containers was observed. The loss amounted to about 10% per transfer. After successfully establishing the collection/sampling procedure for urine by addition of Triton X-100 to the collection vessels (with a purpose of preventing NSB), the method was validated for dalbavancin in the range from 0.05 μg/mL to 50 μg/mL, using 100 μL of urine. These methods were used to quantify dalbavancin in plasma and urine of hospitalized children in a pediatric dalbavancin PK study. Eighteen percent of the total number of plasma study samples was reassayed for incurred samples reproducibility (ISR) and all the reassayed dalbavancin concentrations were within the ± 20% limits. For urine, all the collected samples were reassayed for ISR and the original dalbavancin concentration was confirmed within the ± 20% limits for 17 (94%) samples; the one remaining urine sample had its reassayed concentration confirmed within ± 25% of the original result.     

Determination of stavudine in human plasma and urine by high-performance liquid chromatography using a reduced sample volume

Sensitive high-performance liquid chromatographic assays have been developed for the quantification of stavudine (2′,3′-didehydro-3′-deoxythymidine, d4T) in human plasma and urine. The methods are linear over the concentration ranges 0.025–25 and 2–150 μg/ml in plasma and urine, respectively. An aliquot of 200 μl of plasma was extracted with solid-phase extraction using Oasis^® cartridges, while urine samples were simply diluted 1/100 with HPLC water. The analytical column, mobile phase, instrumentation and chromatographic conditions are the same for both methods. The methods have been validated separately, and stability tests under various conditions have been performed. The detection limit is 12 ng/ml in plasma for a sample size of 200 μl. The bioanalytical assay has been used in a pharmacokinetic study of pregnant women and their newborns.     

Use of online-dual-column extraction in conjunction with chiral liquid chromatography tandem mass spectrometry for determination of terbutaline enantiomers in human plasma

An online sample extraction chiral bioanalytical method was developed and validated for the quantification of terbutaline, a beta2-selective adrenoceptor agonist, spiked into human plasma by using two extraction columns and a chiral stationary phase (CSP) in conjunction with liquid chromatography tandem mass spectrometry (LC-MS/MS). In this method, two Oasis HLB extraction columns were used in parallel for plasma sample purification and a Chirobiotic T CSP was used for enantiomeric separation. Atmospheric pressure chemical ionization MS/MS was employed in multiple reaction monitoring mode for the detection and quantification. Subsequent to the addition of an internal standard solution, the plasma samples were directly injected onto the system for extraction and analysis. This method allowed the use of one of the extraction columns for purification while the other was being equilibrated. Hence, the time required for reconditioning the extraction columns did not contribute to the total analysis time per sample, which resulted in a shorter run time and higher throughput. A lower limit of quantification of 1.0 ng/mL was achieved using only 50 microliter of human plasma. The method was validated with a dynamic range of 1.0-200 ng/mL. The intra- and interday precision was no more than 11% CV and the assay accuracy was between 94-106%.     

Quantification of 3-deazaneplanocin A, a novel epigenetic anticancer agent, in rat biosamples by hydrophilic interaction liquid chromatography-tandem mass spectrometric detection

A sensitive and selective LC-MS/MS based bioanalytical method was developed and validated for the quantification of 3-deazaneplanocin A (DZNep), a novel epigenetic anti-tumor drug candidate, in Sprague-Dawley (SD) rat biosamples (plasma, urine, feces and tissue samples). The method comprises a phenylboronic acid (PBA)-containing solid phase extraction procedure, serving for binding and clean-up of DZNep in rat biosamples spiked with tubercidin (as internal standard). The analytes were separated on an Agilent hydrophilic interaction chromatography (HILIC) column. LC-MS/MS in positive ion mode was used to perform multiple reaction monitoring at m/z of 263/135 and 267/135 for DZNep and tubercidin, respectively. The limit of quantification (LOQ) of DZNep in rat biosamples was 20 ng/mL. The data of intra-day and inter-day accuracy were within 15% of nominal concentration while the precision (relative standard deviation) less than 10% for all biosamples. The extraction recoveries for DZNep and tubercidin were consistent and reproducible (around 80%) and the matrix effects were negligible (around 10% suppression) in all biosamples. This method was demonstrated to be applicable for pharmacokinetic studies of DZNep in SD rats.     

Simple high-performance liquid chromatographic method for determination of losartan and E-3174 metabolite in human plasma, urine and dialysate

A simple high-performance liquid chromatographic (HPLC) method was developed for the determination of losartan and its E-3174 metabolite in human plasma, urine and dialysate. For plasma, a gradient mobile phase consisting of 25 mM potassium phosphate and acetonitrile pH 2.2 was used with a phenyl analytical column and fluorescence detection. For urine and dialysate, an isocratic mobile phase consisting of 25 mM potassium phosphate and acetonitrile (60:40, v/v) pH 2.2 was used. The method demonstrated linearity from 10 to 1000 ng/ml with a detection limit of 1 ng/ml for losartan and E-3174 using 10 μl of prepared plasma, urine or dialysate. The method was utilized in a study evaluating the pharmacokinetic and pharmacodynamic effects of losartan in patients with kidney failure undergoing continuous ambulatory peritoneal dialysis (CAPD).     

Determination of 3'-amino-3'-deoxythymidine, a cytotoxic metabolite of 3'-azido-3'-deoxythymidine, in human plasma by ion-pair high-performance liquid chromatography

A sensitive high-performance liquid chromatographic assay has been developed to determine the levels of 3'-amino-3'-deoxy-thymidine (AMT), a cytotoxic metabolite of 3'-azido-3'-deoxy-thymidine (AZT, zidovudine), in human plasma. The sample pretreatment involved solid-phase extraction using cation-exchange extraction columns. Chromatography was carried out on a C₈ column, using a mobile phase of methanol—0.01 M ammonium acetate (pH 5)—0.25 M sodium dioctylsulfosuccinate (60:40:4, v/v/v) and ultraviolet detection at 265 nm. The method has been validated, and stability tests under various conditions have been performed. The lower limit of quantitation is 5 ng/ml (using 500-μl human plasma samples). The bioanalytical assay has been used for the determination of AMT in patients with AIDS who used AZT.     

Determination of 3-hydroxy-guanfacine in biological fluids by electron-capture gas—liquid chromatography

An electron-capture gas—liquid chromatographic method was developed for measuring 3-hydroxy-guanfacine, the main metabolite of guanfacine in human plasma and urine. After extraction, the metabolite was derivatized by condensing the amidino group with hexafluoroacetylacetone and by methylating the NH and OH groups with methyl iodide. The obtained derivative possessed good bioanalytical gas chromatographic properties, using a capillary column. The O-glucuronide was measured after enzymatic hydrolysis. Unchanged guanfacine could be determined in urine together with its 3-hydroxy metabolite by this method.     

Development and validation of a liquid chromatographic-tandem mass spectrometric method for the determination of galantamine in human heparinised plasma

Galantamine is an acetylcholinesterase inhibitor, recently approved for the treatment of mild-to-moderate Alzheimer's disease. To allow a higher throughput of samples, a new bioanalytical method for the determination of galantamine in human plasma was developed and validated. A stable isotope labelled internal standard was used. Sample preparation consisted of a simple one-step liquid-liquid extraction with toluene. The extracts were analysed with positive ion TurboIonspray tandem mass spectrometry (LC-MS-MS). The method was validated in the 1-500-ng/ml range. The accuracy, precision, selectivity, lower limit of quantification, upper limit of quantification, linearity and extraction recovery were evaluated, as well as the stability of the compound in plasma, blood, methanol and 2% BSA solutions under different conditions. The method proved very rugged during the analysis of large numbers of samples from clinical trials.     

Influence of Obstructive Jaundice on Pharmacodynamics of Rocuronium

Background

Anesthetics are variable in patients with obstructive jaundice. The minimum alveolar concentration awake of desflurane is reduced in patients with obstructive jaundice, while it has no effect on pharmacodynamics and pharmacokinetics of propofol. In this study, we investigated the influence of obstructive jaundice on the pharmacodynamics and blood concentration of rocuronium.

Methods

Included in this study were 26 control patients and 27 patients with obstructive jaundice. Neuromuscular block of rocuronium was monitored by acceleromyography. Onset time, spontaneous recovery of the height of twitch first (T1) to 25% of the final T1 value (Duration 25%, Dur 25%), recovery index (RI), and spontaneous recovery of train-of-four (TOF) ratios to 70% were measured. The plasma rocuronium concentrations were determined by high performance liquid chromatography using berberine as an internal standard.

Results

There was no significant difference in onset time between the two groups. The Dur 25%, the recovery index and the time of recovery of the TOF ratios to 70% were all prolonged in the obstructive jaundice group compared with the control group. The plasma concentration of rocuronium at 60, 90 and 120 min after bolus administration was significantly higher in the obstructive jaundice group.

Conclusions

The neuromuscular blockade by rocuronium is prolonged in obstructive jaundice patients, and therefore precautions should be taken in case of postoperative residual neuromuscular block. The possible reason is impedance of rocuronium excretion due to biliary obstruction and increased plasma unbound rocuronium because of free bilirubin competing with it for albumin binding.     

Effects of neuromuscular blocking agents on central respiratory chemosensitivity in newborn rats

Neuromuscular blocking agents suppress central respiratory activity through their inhibitory effects on preinspiratory neurons and the synaptic drive from preinspiratory neurons to inspiratory neurons. Central CO2-chemosensitive areas, which partly consist of CO2-excited neurons, in the rostral ventrolateral medulla are thought to provide tonic drive to the central respiratory network and involve cholinergic mechanisms, which led us to hypothesize that neuromuscular blocking agents can inhibit CO2-excited neurons and attenuate respiratory CO2 responsiveness. To test this hypothesis, we used isolated brainstem-spinal cord preparations from newborn rats. The increase of C4 burst frequency induced by a hypercapnic superfusate, i.e. respiratory CO2 responsiveness, was suppressed by the application of neuromuscular blocking agents, either d-tubocurarine (10, 100 microM) or vecuronium (100 microM). These agents (40 microM) also induced hyperpolarization and decreases in firing frequency of CO2-excited neurons in the rostral ventrolateral medulla. Our results demonstrate that neuromuscular blocking agents inhibit CO2-excited tonic firing neurons and attenuate respiratory CO2 responsiveness.     

Validation and implementation of a liquid chromatography/tandem mass spectrometry assay for quantitation of the total and unbound RO4929097, a γ-secretase inhibitor targeting Notch signaling, in human plasma

A reversed-phased liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was developed and validated for quantitation of the total and unbound RO4929097, a γ-secretase inhibitor targeting Notch signaling, in human plasma. Sample preparation involved a liquid-liquid extraction with ethyl acetate. Chromatographic separation was achieved on a Waters X-Terra? MS C(18) column with an isocratic mobile phase consisting of methanol/0.45% formic acid in water (60:40, v/v) running at a flow rate of 0.2 ml/min for 6 min. The lower limits of quantitation (LLOQs) were 5 ng/ml for the total RO4929097 in plasma and 0.5 ng/ml for the unbound drug in phosphate buffer solution (PBS). Calibration curves were linear over RO4929097 concentration range of 5-2000 ng/ml in plasma for the total drug and 0.5-200 ng/ml in PBS for the unbound drug. The intra-day and inter-day accuracy and precision were within the generally accepted criteria for bioanalytical method (<15%). The method has been successfully employed to characterize the total and unbound plasma pharmacokinetics of RO4929097 after its oral administration in cancer patients.     

A novel spectrofluorimetric method for determination of imatinib in pure,pharmaceutical preparation,human plasma,and human urine

The following paper represents a simple, highly sensitive, responsive validated and developed spectrofluorimetric method for estimation of imatinib (IMB) in its pure, commercial preparation, human urine and human blood plasma. The calibration curve was in the range 4–900 ng ml^?1 for pure form and urine and 8–900 ng ml^?1 for plasma in a medium contains carboxymethyl cellulose (CMC) and acetate buffer (pH 5) with excitation wavelength (λ_ex) 230 nm and emission wavelength (λ_em) 307 nm. The limit of detection (LOD) was 0.37 ng ml^?1 for the pure form, 0.64 ng ml^?1 for human urine, and 0.70 ng ml^?1 for human plasma, while the limit of quantitation (LOQ) was 1.2 for pure form, 1.91 for urine and 2.1 for plasma. The suggested method was successfully applied for evaluation of IMB in tablets within 99% mean percentage recovery. The excipients that are usually used as additives in pharmaceutical dosage form did not interfere with the suggested method. The method was efficiently used for estimation of IMB in human urine and human plasma. The effect of some cations that might be present in urine and plasma was also studied. The method was also focused on human volunteers and in vitro drug release.