Pancuronium Research Articles

Validation of an HPLC Analytical Method for Determination of Pancuronium Bromide in Pharmaceutical Injections

Pancuronium bromide is used with general anesthesia in surgery for muscle relaxation and as an aid to intubation. A high performance liquid chromatographic method was fully validated for the quantitative determination of pancuronium bromide in pharmaceutical injectable solutions. The analytical method was performed on an amino column (Luna® 150 mm × 4.6 mm, 5 µm). The mobile phase was composed of acetonitrile:water containing 50 mmol L−1 of 1-octane sulfonic acid sodium salt (20:80 v/v) with a flow rate of 1.0 mL min−1 and ultraviolet (UV) detection at 210 nm. The proposed analytical method was compared with that described in the British Pharmacopoeia.

Length-tension relationship of the external anal sphincter muscle: implications for the anal canal function

The length at which a muscle operates in vivo (operational length) and the length at which it generates maximal force (optimal length) may be quite different. We studied active and passive length-tension characteristics of external anal sphincter (EAS) in vivo and in vitro to determine the optimal and operational length of rabbit EAS. For the in vitro studies, rings of EAS (n = 4) were prepared and studied in a muscle bath under isometric conditions. For in vivo studies, female rabbits (n = 19) were anesthetized and anal canal pressure was recorded by use of a sleeve sensor placed in the custom-designed catheter holders of 4.5-, 6-, and 9-mm diameters. Measurements were obtained at rest and during EAS electrical stimulation. Sarcomere length of EAS muscle was measured by laser diffraction technique with no probe and three probes in the anal canal. In vitro studies revealed 2,054 mN/cm(2) active tension at optimal length. In vivo studies revealed a probe size-dependent increase in anal canal pressure and tension. Maximal increase in anal canal tension with stimulation was recorded with the 9-mm probe. Increases in anal canal tension with increase in probe size were completely abolished by pancuronium bromide. EAS muscle sarcomere length without and with 9-mm probe in the anal canal were 2.11 +/- 0.08 and 2.99 +/- 0.07 microm, respectively. Optimal sarcomere length, based on the thin filament length measured by thin filament analysis, is 2.44 +/- 0.10 microm. These data show that the operational length of EAS is significantly shorter than its optimal length. Our findings provide insight into EAS function and we propose the possibility of increasing anal canal pressure by surgical manipulation of the EAS sarcomere length.

Hearing impairment in congenital diaphragmatic hernia: the inaudible and noiseless foot of time

Infants with congenital diaphragmatic hernia (CDH) are at high risk of sensorineural hearing loss (SNHL). Extracorporeal membrane oxygenation is known to increase this risk, but little is known about other potential causes. We evaluated the impact of several risk factors on SNHL development in CDH survivors not treated with extracorporeal membrane oxygenation. All high-risk CDH survivors consecutively treated between 1999 and 2005 were included. SNHL was diagnosed based on formal assessment with standard audiologic tests. Patients with and without SNHL were compared for patient-related and treatment-related risk factors. Subsequently, a logistic regression analysis was performed to identify independent risk factors associated with SNHL development. Out of 87 CDH survivors, 82 had a formal audiologic evaluation and 40 (49%) had SNHL. Patients with SNHL had significantly lower gestational age (P = .045); higher prevalence of sepsis (P < .001); older age at audiologic examination (P < .001); more episodes of hypocapnia (P = .045); higher prevalence of inhaled nitric oxide use (P = .005); longer mechanical ventilation (P = .009); and longer aminoglycosides (P = .006), furosemide (P = .004), and pancuronium bromide (P = .001) treatments. On logistic regression analysis, the only variable independently associated with the development of SNHL was patient's age at audiologic follow-up (P = .012). Several risk factors were associated with SNHL development at univariate analysis. After logistic regression, only age at evaluation remained independently associated with SNHL. Routine audiologic follow-up is advocated in all CDH patients. Further studies are needed to define if other (genetic) factors may be involved in the pathogenesis of SNHL in patients with CDH.

Physicians and Execution

This spring the U.S. Supreme Court in Baze v. Rees 1 will rule on the constitutionality of the three-drug regimen currently used for lethal injection in most state executions. The Eighth Amendment to the U.S. Constitution prohibits punishment that is “cruel and unusual.” The central question before the Court in Baze is whether the use of sodium thiopental, pancuronium bromide, and potassium chloride violates that constitutional prohibition. The heinous nature of the crimes committed by Ralph Baze and his coplaintiff, Thomas Bowling, is not in doubt. What the Court will decide is whether the current lethal-injection protocol does or does not . . .

Lethal Injection and Physicians

EGAL EXECUTION BY LETHAL INJECTION HAS MADE NAtionalheadlinesduringthepast2yearsbecauseprisoners have argued that it poses an unnecessary risk of pain as currently performed and therefore constitutesunconstitutionalcruelandunusualpunishment.The most widely used method of lethal injection, developed by aphysician, 1 involvestheintravenousinfusionoflargedoses of sodium thiopental to induce deep sleep, pancuronium bromide as a paralyzing agent, and potassium chloride for cardioplegia. Lethal injectionwas adopted as a means of execution because it seemed more humane than other methods, but it is unclear what consideration was given to the selectionofexecutionpersonnel,theskillstheyneeded,and thetrainingtheymightrequire.Recentcourtchallengeshave revealedthatdrugdosagesarenotuniformamongthestates, sowidedisparitiesinlevelsofsedationmayoccur,andsome inmates may have experienced considerable pain after potassium chloride infusion. 2,3 The legal challenges have also publicly exposed the participation of physicians in executions. 4,5 A number of states suspendedexecutionstoreexaminetheirmethods 6 andhave considered escalating the role of physicians to meet constitutionalchallenges.Theseeventshaveraisedquestionsabout theeffectofprofessionalethicalstandardsonphysicianparticipation in capital punishment and about the response of the medical profession to known instances of physician involvement in executions.

Anaphylaxis during anesthesia - role of skin prick testing in diagnosing multiple sensitivities.

The true incidence of anaphylactic reactions and their associated morbidity and mortality remain poorly defined. This is due to uncertainties in reporting accuracy and exhaustivity. A 23 years old male developed severe anaphylaxis under general anesthesia with cardiovascular collapse, bronchospasm and angio-edema. He was promptly managed with intravenous Adrenaline, Hydrocortisone, colloid solutions and Promethazine. The temporal relation suggested Atracurium to be the cause. However, skin prick test, performed 8 weeks later, showed a very strong (+++) positive test for Atracurium and mild sensitivity (+) with Suxamethonium. No sensitivity to Nalbuphine, Thiopentone or Pancuronium was noted. The relevant information was endorsed in patient's medical record sheet for his future exposure.

Lethal Injection for Execution: Chemical Asphyxiation?

BackgroundLethal injection for execution was conceived as a comparatively humane alternative to electrocution or cyanide gas. The current protocols are based on one improvised by a medical examiner and an anesthesiologist in Oklahoma and are practiced on an ad hoc basis at the discretion of prison personnel. Each drug used, the ultrashort-acting barbiturate thiopental, the neuromuscular blocker pancuronium bromide, and the electrolyte potassium chloride, was expected to be lethal alone, while the combination was intended to produce anesthesia then death due to respiratory and cardiac arrest. We sought to determine whether the current drug regimen results in death in the manner intended.Methods and FindingsWe analyzed data from two US states that release information on executions, North Carolina and California, as well as the published clinical, laboratory, and veterinary animal experience. Execution outcomes from North Carolina and California together with interspecies dosage scaling of thiopental effects suggest that in the current practice of lethal injection, thiopental might not be fatal and might be insufficient to induce surgical anesthesia for the duration of the execution. Furthermore, evidence from North Carolina, California, and Virginia indicates that potassium chloride in lethal injection does not reliably induce cardiac arrest.ConclusionsWe were able to analyze only a limited number of executions. However, our findings suggest that current lethal injection protocols may not reliably effect death through the mechanisms intended, indicating a failure of design and implementation. If thiopental and potassium chloride fail to cause anesthesia and cardiac arrest, potentially aware inmates could die through pancuronium-induced asphyxiation. Thus the conventional view of lethal injection leading to an invariably peaceful and painless death is questionable.

Clarification of cyanide’s effect on oxygen transport characteristics in a canine model

Objective: To clarify the cardiovascular mechanisms of cyanide poisoning by evaluating oxygen transport characteristics using a canine model. Methods: A prospective controlled experiment was performed at a hospital-based animal laboratory....

Screening procedure for the analysis of distigmine bromide in serum by high-performance liquid chromatography–electrospray ionization mass spectrometry

A screening procedure was developed for the identification and quantification of distigmine bromide in serum samples by using liquid chromatography (LC)–electrospray ionization (ESI)-mass spectrometry (MS). In this method, distigmine bromide was analyzed in 0.5 mL serum by using pancuronium bromide as the internal standard, and gradient elution was performed using a reversed-phase column and a mixture of 10 mM-ammonium formate and methanol as the mobile phase. A highly sensitive assay could be performed with simple solid phase extraction using a cation exchange cartridge column by carrying out selected ion monitoring analysis in the positive ion detection mode. The procedure was validated in terms of linearity (0.997 < r 2 < 0.999 for concentrations ranging from 5 to 250 ng/mL), extraction recovery (83.0% to 89.3%, n = 5), and detection limit (S/N ratio, >3 at 2.5 ng/mL). The inter- and intra-day precisions (coefficient of variation; CV%) were <8.5% and <9.7%, respectively. The analytes were evaluated for stability and were found to be stable in serum for 1 week at 4 °C and 4 weeks at −30 °C, and successfully applied to in the analysis of two overdose cases. This method is sensitive and useful for the detection, quantification, and confirmation of distigmine bromide in serum.

A modification of the kinetic determination of pancuronium bromide based on its inhibitory effect on cholinesterase

A modification of the existing spectrophotometric kinetic method for the determination of pancuronium bromide (PCBr), based on pooled human serum cholinesterase (ChE, EC 3.1.1.8 acylcholine acylhydrolase) inhibition, was developed. Butyrylthiocholine iodide (concentration 1.667 mmol/L) was used as substrate and determination was performed at pH 7.6. Essential basic kinetic parameters were also determined: Michaelis-Menten's constant KM=0.33 mmol/L, maximal reaction rate Vmax=42.29 micromol/L min, inhibition constant KI=0.34 micromol/L, and IC50=0.235 micromol/L. Linear dependence between the reaction rate and the inhibitor concentration exists in PCBr concentration range 8.29-265.28 nmol/L, which corresponds to the real sample concentrations from 0.166 to 5.306 micromol/L. The method detection limit was established to be 1.86 nmol/L and the quantification limit was 6.18 nmol/L. Precision of the method was tested for three pancuronium concentrations (16.58, 99.48, and 198.96 nmol/L). The relative standard deviation (RSD) was in the range 0.78-5.13%. Accuracy was examined by the standard addition method. The influence of substances usually present in serum and urine on the reaction rate was determined. The method developed was applied for PCBr determination in spiked serum and urine samples and in the urine taken during surgery. The method was proven to have good sensitivity, accuracy, and precision and can be considered suitable for clinical practice.

Risk factors for sensorineural hearing loss in survivors with severe congenital diaphragmatic hernia

Recent improvements in perinatal management have improved the prognosis in patients with severe congenital diaphragmatic hernia (CDH). However, in surviving patients with severe CDH, hearing loss has sometimes been reported to occur during the follow-up period. Although some of the risk factors for developing sensorineural hearing loss (SNHL) have been reported in CDH, no definitive risk factors have yet been reported. We, therefore, investigated the risk factors regarding postnatal management in patients with severe CDH. In 16 surviving patients with severe CDH, which had all been detected antenatally, and whose lung-to-thoracic ratio was less than 0.2, four patients demonstrated late onset SNHL, which occurred between 1.5 and 5 years of age. The risk factors for SNHL regarding the postnatal treatment for CDH were analyzed between the four patients with SNHL and the remaining 12 patients without SNHL, regarding such factors as the use of ototoxic drugs, neuromuscular blocking agents, high-frequency oscillation (HFO), and inhaled nitric oxide, the duration of hypocapnia, hypoxia, severe acidosis, severe alkalosis, and mechanical ventilation. In addition, the types of neuromuscular blocking agents were also analyzed, including the administration of pancuronium bromide (PB) and vecuronium bromide (VB). The patients with SNHL were found to have a significantly higher risk than the patients without SNHL regarding the duration of loop diuretics usage and the duration of usage of both mechanical ventilation and HFO. Furthermore, all four patients with SNHL used PB. In contrast, none of the five patients using VB developed SNHL The duration and cumulative dose of PB used in the patients with severe CDH showed a significant correlation to the occurrence of SNHL. Although this study was retrospective, based on our data, the prolonged use of PB, in addition to the duration of treatment by loop diuretics, mechanical ventilation, and HFO usage, might, thus, be suggested to be a possible risk factor for late onset SNHL in patients with severe CDH.

Cholinesterase inhibition based determination of pancuronium bromide in biological samples

Pancuronium bromide (PCBr) inhibition effect on enzyme cholinesterase from pooled human serum (Che, EC 3.1.1.8 acylcholine acylhydrolase) was used for development of a spectrophotometric kinetic method for PCBr determination in human serum and urine. Optimal conditions for the basic and inhibitor reactions were established: pH=7.7 and substrate concentration c(benzoylcholine chloride)=1.33 mmol/L. Kinetic parameters were also determined: Michaelis-Menten's constant K(M)=0.40 mmol/L, maximal reaction rate V(max)=52.2 micromol/L min, inhibition constant K(i)=0,56 micromol/L and IC(50)=1.31 micromol/L. Linear dependence between the reaction rate and inhibitor concentration exists in PCBr concentration range 8.20-68.25 nmol/L, which corresponds to the real sample concentrations from 0.328 to 2.730 micromol/L. The method detection and quantification limits were 2.01 nmol/L and 6.67 nmol/L, respectively. Precision of the method was tested for three pancuronium concentrations (10.70, 29.35 and 51.25 nmol/L). Relative standard deviation (RSD) was in the range 0.15-7.45%. Accuracy was examined by standard addition method. Influence of the substances usually present in serum and urine on the reaction rate was tested. The developed method was applied for PCBr content determination in serum model samples, urine model samples and in urine taken during surgery. The method has good sensitivity, accuracy, precision and it is suitable for clinical practice.

PROLONGED NEUROMUSCULAR BLOCKADE

We are presenting a case of prolonged neuromuscular blockade afteremergency cesarean section. A 34 years old, young lady with no previous history of any systemic illness includingneuromuscular disorder reported in the operation t heatre for cesarean section. She was offered standard protocol forgeneral anaesthesia using thiopentone sodium i/v for induction, suxamethonium i/v for intubation, and pancuroniumbromide i/v for intra-operative relaxation. Intra-operative analgesia was obtained with nalbuphine i/v (after delivery ofchild). Ampicillin and gentamicin i/v were used as prophylactic antibiotics. The patient failed to regain spontaneousbreathing effort after a lapse of two hours since the last dose of pancuronium bromide. Laboratory investigationsincluding complete blood picture, urea, creatinine, electrolytes (calcium, sodium, potassium) revealed anemia andsevere hypocalcemia. She was given fresh whole blood and calcium gluconate intravenously, in addition to othersupportive measures like ventilatory support using SIMV mode of ventilation with 40% O2. Patient started regainingbreathing effort after about 12 hours and was extubated after about 15 hours of artificial ventilation with little residualneuromuscular blocking effect. She was kept in the ICU for the next 24 hours for observation and was discharged fromICU the next day with full recovery. Conclusion Patient probably suffered from the interaction between gentamicin andpancuronium bromide, that was further potentiated by hypocalcemia and anaemia. She was given supportive care alongwith replacement of calcium, and anaemia was corrected by fresh whole blood transfusion. Patient recovereduneventfully and was discharged from ICU the next day.

Effect of electrical stimulation of the internal capsule on nociceptive neurons responding to orofacial stimuli in the medullary dorsal horn of the rat

Internal capsule (IC) stimulation has been used clinically to alleviate central pain. However, the neuronal mechanisms underlying pain relief by IC stimulation are poorly understood. In order to elucidate the analgesic mechanism, the effect of IC conditioning stimulation on nociceptive neurons in the rat medullary dorsal horn was investigated in the present study. Rats were anaesthetized with N(2)O-O(2) (2:1) and 0.5% halothane and were immobilized with pancuronium bromide. Two kinds of nociceptive neurons, wide dynamic range (WDR) and nociceptive specific (NS) neurons, responding to noxious stimulations of the face and oral structures were recorded in the trigeminal caudal nucleus and the medial reticular subnuclei. A test stimulus with a single rectangular pulse (2ms in duration, 5-70V) was applied to the centre of the receptive field. Responses in 55.9% of the WDR neurons and in 60% of the NS neurons were inhibited by conditioning stimuli to the ipsilateral IC with trains of 33 pulses (100-300microA) at 330Hz. The percents of peak inhibitory effects on WDR neurons and NS neurons were 78.1+/-25.0% (n=19) and 89.0+/-13.6% (n=3), respectively. The inhibitory effect continued for conditioning-test intervals of up to 500ms. Effective sites for conditioning stimulation were concentrated in the lateral side of the IC. These findings suggest that modulation of nociceptive transmission by IC stimulation occurs at second-order neurons via a presynaptic phenomenon by corticofugal fibers in the IC.

Simultaneous determination of pancuronium, vecuronium and their related compounds using LC–ESI-MS

A simultaneous determination method of quaternary amino steroidal muscle relaxants, pancuronium (PAN), vecuronium (VEC), and 17-monodesacetyl pancuronium (17-OH-PAN), 3,17-bisdesacetyl pancuronium (3,17-OH-PAN), 3-monodesacetyl vecuronium (3-OH-VEC), 3,17-bisdesacetyl vecuronium (3,17-OH-VEC) in human serum was developed using liquid chromatography–electrospray ionization-mass spectrometry (LC–ESI-MS). The weak cation exchange cartridge was useful for the extraction of these compounds. Under optimized LC–ESI-MS conditions, these compounds were almost fully separated within 6.5 min. Linear responses over the concentration range 0.25–50.0 ng/mL were demonstrated for each compound. The developed method successfully detected VEC, 3-OH-VEC and 3,17-OH-VEC in serum intravenously administered with VEC. The level of 3-OH-VEC was higher than other compounds. This suggested that 3-OH-VEC was useful as a forensic probe in VEC administration.

Early effects of embryonic movement: 'a shot out of the dark'.

It has long been appreciated that studying the embryonic chick in ovo provides a variety of advantages, including the potential to control the embryo's environment and its movement independently of maternal influences. This allowed early workers to identify movement as a pivotal factor in the development of the locomotor apparatus. With an increasing focus on the earliest detectable movements, we have exploited this system by developing novel models and schemes to examine the influence of defined periods of movement during musculoskeletal development. Utilizing drugs with known neuromuscular actions to provoke hyperactivity (4-aminopyridine, AP) and either rigid (decamethonium bromide, DMB) or flaccid (pancuronium bromide, PB) paralysis, we have examined the role of movement in joint, osteochondral and muscle development. Our initial studies focusing on the joint showed that AP-induced hyperactivity had little, if any, effect on the timing or scope of joint cavity elaboration, suggesting that endogenous activity levels provide sufficient stimulus, and additional mobilization is without effect. By contrast, imposition of either rigid or flaccid paralysis prior to cavity formation completely blocked this process and, with time, produced fusion of cartilaginous elements and formation of continuous single cartilaginous rods across locations where joints would ordinarily form. The effect of these distinct forms of paralysis differed, however, when treatment was initiated after formation of an overt cavity; rigid, but not flaccid, paralysis partly conserved precavitated joints. This observation suggests that 'static' loading derived from 'spastic' rigidity can act to preserve joint cavities. Another facet of these studies was the observation that DMB-induced rigid paralysis produces a uniform and specific pattern of limb deformity whereas PB generated a diverse range of fixed positional deformities. Both also reduced limb growth, with different developmental periods preferentially modifying specific osteochondral components. Changes in cartilage and bone growth induced by 3-day periods of flaccid immobilization, imposed at distinct developmental phases, provides support for a diminution in cartilage elaboration at an early phase and for a relatively delayed influence of movement on osteogenesis, invoking critical periods during which the developing skeleton becomes receptive to the impact of movement. Immobilization also exerts differential impact along the proximo-distal axis of the limb. Finally, our preliminary results support the possibility that embryonic hyperactivity influences the potential for postnatal muscle growth.

Respiratory modulation of thoracic sympathetic nerve activity increased following brief hypoxia in the rat in situ preparation

Recently (Dick et al., AJP 286: R1121–8, 2004.) we described a form of short-term plasticity expressed by splanchnic sympathetic nerve activity (sSNA) in an anesthetized in vivo rat (Sprague Dawley) model. The sSNA became more respiratory modulated after a brief exposure to hypoxia (8% for 45s). We hypothesized that this property is expressed by other sympathetic nerves, in other rodent strains, and in the more reduced in situ preparation. To test this hypothesis, we recorded thoracic chain sympathetic nerve activity (thSNA) in the working heart-brainstem preparation before and after brief exposure to hypoxic perfusion. Wistar rats (86–100g) were anesthetized, bisected below the diaphragm, and decerebrated precollicularly. The preparation was perfused with artificial cerebrospinal fluid (aCSF) saturated with 95% O2/5% CO2, and paralyzed with pancuronium bromide. Perfusion pressure was maintained above 50 mmHg with vasopressin (10ul − 4uM added to perfusate). We recorded phrenic, thSNA, and perfusion pressure before and after hypoxic perfusion. The PCO2 in the perfusate was increased from 5% to 8 % during the hypoxic challenge mimic an apneic event. Thus, responses were elicited in each animal by switching from 95% O2/5%CO2 to 12% O2/8% CO2 (80% N2) aCSF for 45s. Respiratory modulation of thSNA increased following the hypoxic response. We conclude that short-term plasticity of the sympatho-respiratory system can be generalized to other sympathetic nerves and other rodent strains and remains a property of this reduced preparation. (HL-25830).

Epidural cooling for selective brain hypothermia in porcine model

Hypothermia has been shown to be neuroprotective in many animal models and several human trials of brain ischemic and trauma. However systemic hypothermia may result in fatal complications. This study was undertaken to test epidural cooling as a new method of inducing selective brain hypothermia. Six adult swine (mean mass, 33.8+/-3.6 kg) were studied. Anesthesia was maintained with pentobarbital sodium (25 mg kg-1, i.v.) and pancuronium bromide (0.5 mg kg-1 h-1, i.v.). Five probes were placed in the rectum, deep brain, brain surface, epidural space, and room air for temperature monitoring respectively. Epidural cooling was performed using cold-saline (4 degrees C) perfusion into the epidural space through a flexible double-lumen catheter. The dripping speed of cold saline was controlled to maintain the target temperature. The changes of the epidural space pressure, complete blood counts, basic metabolic panels, tests for fibrinolysis and coagulation status were monitored to assess hypothermia-induced changes. Following the epidural cooling perfused with cold-saline (4 degrees C) at mean dripping speed of 720 ml per hour, the local brain surface temperature could decrease rapidly to 17.3-21.6 degrees C within one minute, and deep brain temperature decreased to 27.2-29.7 degrees C within 5 minutes. The target temperatures were easily controlled by the dripping speed of cold saline (from mild to deep hypothermia). The rectal temperature was maintained at normal range within 6 perfusion hours. No arrhythmia was observed, and all hematological variables were within the normal range for swine. No increased intracranial pressure was induced by the cooling method. The data demonstrate that epidural space cooling was technically feasible and useful for selective brain hypothermia, and the target temperatures are easily controlled. The induction of hypothermia was rapid and maintained for a long period of time, whereas the body temperature was maintained within the normal range and without hemodynamic instability.

Parasympathetic Mediated Pupillary Dilation Elicited by Lingual Nerve Stimulation in Cats

To determine the autonomic efferent nerve pathways for the reflex pupillary dilation elicited by somatic stimulation in cats. Cats anesthetized with a mixture of alpha-chloralose (50 mg/kg) and urethane (100 mg/kg) were intubated and paralyzed by intravenous injection of pancuronium bromide. The central cut end of the lingual nerve (LN) was stimulated electrically to simulate somatic stimulation, and 1 microL of lidocaine (2%) was microinjected into the Vsp or the EW nucleus to determine its effect on the pupillary dilation induced by LN stimulation. The effect of electrically stimulating the Vsp or sectioning the superior cervical sympathetic nerve (CSN) on the pupillary response was also examined. Stimulation of the LN or the trigeminal spinal nucleus (Vsp) evoked pupillary dilation in a frequency- and intensity-dependent manner. These responses were not affected by sectioning the ipsilateral or both CSNs. The pupillary responses were markedly suppressed by microinjecting lidocaine into the ipsilateral Vsp or the Edinger-Westphal (EW) nucleus, but not by injection into the contralateral Vsp. These results indicate that the Vsp and EW nucleus act as bulbar relay centers for pupillary dilation elicited by LN stimulation and suggest that the efferent arc of the response is a parasympathetic pathway. The contralateral pupillary dilation appears to be mediated, at least in part, by fibers projecting from the Vsp to the contralateral EW nucleus.

Rapid Determination of Gallamine Triethiodide (Flaxedil®) and Pancuronium Bromide (Pavulon®) in Pharmaceutical and Urine Matrices by Means of Modified‐Carbon‐Paste Ion‐Selective Electrodes

AbstractA new analytical method for the determination of gallamine triethiodide (Flaxedil®; 1) and pancuronium bromide (Pavulon®; 2), two muscle relaxants used in surgical operations and in pain relief, has been developed. Our approach relies on rapid, precise, and sensitive potentiometric sensors based on modified‐carbon‐paste ion‐selective electrodes (CP‐ISEs). Linear calibration graphs in the working ranges of ca. 4.5–892 and 7.3–733 μg/ml (in H2O, pH 7.0, T=25°) were established for 1 and 2, respectively; and Nernst slopes corresponding to three‐ or two‐electrons transfers, respectively, were obtained. The method works best in a pH range of 7–9. Average relative errors of 2.12 and 2.14%, with average standard deviations of 1.98–2.47 and 2.64–3.45, respectively, were obtained for urine samples of 1 and 2. The corresponding relative errors for the pharmaceutical samples were 1.59 and 1.64%, with standard deviations of 0.54–1.34 and 0.52–1.67, respectively. Statistical Student and F tests were applied to the data, and satisfactory results were obtained.