Study of the interaction between hydroxymethylnitrofurazone and 2-hydroxypropyl-beta-cyclodextrin

Chagas disease is a serious health problem in Latin America. Hidroxymethylnitrofurazone (NFOH) is a nitrofurazone prodrug more active than nitrofurazone against Trypanosoma cruzi. However, NFOH presents low aqueous solubility, high photodecomposition and high toxicity. The present work is focused on the characterization of an inclusion complex of NFOH in 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD). The complexation with HP-beta-CD was investigated using reversed-phase liquid chromatography, solubility isotherms and nuclear magnetic resonance. The retention behavior was analyzed on a reversed-phase C-18 column, using acetonitrile-water (20/80, v/v) as the mobile phase, in which HP-beta-CD was incorporated as a mobile phase additive. The decrease in the retention times with increasing concentrations of HP-beta-CD enables the determination of the apparent stability constant of the complex (K = 6.2 +/- 0.3 M-1) by HPLC. The solubility isotherm was studied and the value for the apparent stability constant (K = 7.9 +/- 0.2 M-1) was calculated. The application of continuous variation method indicated the presence of a complex with 1:1 NFOH:HP-beta-CD stoichiometry. The photostability study showed that the formation of an inclusion complex had a destabilizing effect on the photodecomposition of NFOH when compared to that of the ""free"" molecule in solution. The mobility investigation (by NMR longitudinal relaxation time) gives information about the complexation of NFOH with HP-beta-CD. In preliminary toxicity studies, cell viability tests revealed that inclusion complexes were able to decrease the toxic effect (p < 0.01) caused by NFOH. (c) 2008 Elsevier B.V. All rights reserved.

Epidermal iontophoresis: II. Application of the ionic mobility-pore model to the transport of local anesthetics

Purpose, An in vitro study was carried out to determine the iontophoretic permeability of local anesthetics through human epidermis. The relationship between physicochemical structure and the permeability of these solutes was then examined using an ionic mobility-pore model developed to define quantitative relationships. Methods. The iontophoretic permeability of both ester-type anesthetics (procaine, butacaine, tetracaine) and amide-type anesthetics (prilocaine, mepivacaine, lidocaine, bupivacaine, etidocaine, cinchocaine) were determined through excised human epidermis over 2 hrs using a constant d.c. current and Ag/AgCl electrodes. Individual ion mobilities were determined from conductivity measurements in aqueous solutions. Multiple stepwise regression was applied to interrelate the iontophoretic permeability of the solutes with their physical properties to examine the appropriateness of the ionic mobility-pore model and to determine the best predictor of iontophoretic permeability of the local anesthetics. Results. The logarithm of the iontophoretic permeability coefficient (log PCj,iont) for local anesthetics was directly related to the log ionic mobility and MW for the free volume form of the model when other conditions are held constant. Multiple linear regressions confirmed that log PCj,iont was best defined by ionic mobility (and its determinants: conductivity, pK(a) and MW) and MW. Conclusions. Our results suggest that of the properties studied, the best predictors of iontophoretic transport of local anesthetics are ionic mobility (or pK(a)) and molecular size. These predictions are consistent with the ionic mobility pore model determined by the mobility of ions in the aqueous solution, the total current, epidermal permselectivity and other factors as defined by the model.

Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial

Background Epidural block is widely used to manage major abdominal surgery and postoperative analgesia, but its risks. and benefits are uncertain. We compared adverse outcomes in high-risk patients managed for major surgery with epidural block or alternative analgesic regimens with general anaesthesia in a multicentre randomised trial. Methods 915 patients undergoing major abdominal surgery with one of nine defined comorbid states to identify high-risk status were randomly assigned intraoperative epidural anaesthesia and postoperative epidural analgesia for 72 h with general anaesthesia (site of epidural selected to provide optimum block) or control. The primary endpoint was death at 30 days or major postsurgical morbidity. Analysis by intention to treat involved 447 patients assigned epidural and 441 control. Findings 255 patients (57.1%) in the epidural group and 268 (60.7%) in the control group had at least one morbidity endpoint or died (p=0.29). Mortality at 30 days was low in both groups (epidural 23 [5.1%], control 19 [4.3%], p=0.67). Only one of eight categories of morbid endpoints in individual systems (respiratory failure) occurred less frequently in patients managed with epidural techniques (23% vs 30%, p=0.02). Postoperative epidural analgesia was associated with lower pain scores during the first 3 postoperative days. There were no major adverse consequences of epidural-catheter insertion. Interpretation Most adverse morbid outcomes in high-risk patients undergoing major abdominal surgery are not reduced by use of combined epidural and general anaesthesia and postoperative epidural analgesia. However, the improvement in analgesia, reduction in respiratory failure, and the low risk of serious adverse consequences suggest that many high-risk patients undergoing major intra-abdominal surgery will receive substantial benefit from combined general and epidural anaesthesia intraoperatively with continuing postoperative epidural analgesia.

Response to The quality of epidural Anesthesia is crucial in the assessment of periciperative outcome

In their letter, Gogarten et al. question the effectiveness of the epidural regimens across the trial centers. In our original publication (1), we clearly demonstrated that patients in the epidural group had a working epidural block intraoperatively (evidenced by significantly more hypotension) and postoperatively (evidenced by significantly improved pain scores for 3 days).

Outcomes and safety of drug provocation tests

Drug provocation tests (DPTs) are considered the gold standard for identifying adverse drug reactions (ADRs). The aim of this study was to analyze DPT results and discuss severe systemic reactions associated with them. This was a retrospective analysis of 500 patients with ADRs who sought treatment and were submitted to DPTs when indicated between 2006 and 2010. We performed DPTs according to the European Network for Drug Allergy recommendations. Single-blind, placebo-controlled DPTs were performed with antibiotics, local anesthetics, and nonsteroidal anti-inflammatory drugs, as well as with other drugs. Patient characteristics, DPT results, and reactions were analyzed. The sample comprised 198 patients (80.8% of whom were female patients) submitted to 243 DPTs. Ages ranged from 9 to 84 years (mean, 39.9 years). The 243 DPTs were performed with local anesthetics (n = 93), antibiotics (n = 19), acetaminophen (n = 44), benzydamine (n = 33), COX-2 inhibitors (n = 26), dipyrone (n = 7), aspirin (n = 4), or other drugs (n = 17). The results of 4 tests (1.6%) were inconclusive, whereas those of 10 (4.1%) revealed positive reactions to antibiotics (2/19), COX-2 inhibitors (2/26), acetaminophen (3/44), and local anesthetics (3/93). Two severe reactions were observed: cephalexin-induced anaphylactic shock and bupivacaine-induced anaphylaxis without shock. Four patients (2.0%) reacted to the placebo before administration of the drug. Drug provocation tests are safe for use in clinical practice but they should be placebo-controlled and should be performed under the supervision of an allergist. To confirm a presumptive diagnosis and to manage allergies appropriately, it is crucial to perform DPTs. (Allergy Asthma Proc 32:301-306, 2011; doi: 10.2500/aap.2011.32.3450)

Hyaluronidase shortens levobupivacaine lumbosacral epidural anaesthesia in dogs

Methods: Six adult mixed breed dogs (two males and four females) weighing 7 to 14 kg (10 center dot 5 +/- 1 center dot 5 kg) and aged two to five years were used. Each dog received both treatments in random order: levobupivacaine alone (LBA; n=6) or levobupivacaine plus hyaluronidase (LBH; n=6) administered in the lumbosacral epidural space. Systemic effects, spread and duration of anaesthesia and motor block were determined before treatment and at predetermined intervals. Results: The duration of local anaesthesia was 90 +/- 10 minutes (P=0 center dot 001) for LBH treatment and 150 +/- 15 minutes for LBA treatment. In the LBH treatment, anaesthesia reached the T12 to T13 dermatome and in the LBA treatment it reached the T11 to T12 dermatome in all animals in 5 and 15 minutes, respectively. Complete motor blockade was 75 +/- 12 minutes (P=0 center dot 01) and 120 +/- 15 minutes for LBH and LBA treatments, respectively. Clinical Significance: Hyaluronidase added to levobupivacaine significantly shortens the duration of epidural anaesthesia with the same dermatome spread into the epidural space in dogs.

Distribution of fentanyl in the placental intervillous space and in the different maternal and fetal compartments in term pregnant women

Fentanyl is used in obstetrical practice to promote analgesia and anesthesia during labor and in cesarean delivery, with rapid and short-term effects. To determine fentanyl concentrations in maternal plasma, in the placental intervillous space, and in the umbilical artery and vein in term pregnant women. Ten healthy pregnant women underwent epidural anesthesia with fentanyl plus bupivacaine and lidocaine, and fentanyl concentrations were determined in the various maternal and fetal compartments, including the placental intervillous space, which has not been previously studied in the literature. The ratios of fentanyl concentrations in the various maternal and fetal compartments revealed an 86% rate of placental fentanyl transfer. The highest fentanyl concentrations were detected in the placental intervillous space, being 2.19 times higher than in maternal plasma, 2.8 times higher than in the umbilical vein and 3.6 times higher than in the umbilical artery, with no significant differences between the umbilical vein and artery, demonstrating that there was no drug uptake by fetal tissues nor metabolism of the drug by the fetus despite the high rates of placental transfer. The present study demonstrated that the placental intervillous space acted as a site of fentanyl deposit, a fact that may be explained by two hypotheses: (1) the blood collected from the placental intervillous space is arterial and, according to some investigators, the arterial plasma concentrations of the drugs administered to patients undergoing epidural anesthesia are higher than the venous concentrations, and (2) a possible role of P-glycoprotein (P-gp).

Pharmacokinetics of lidocaine and its metabolite in peridural anesthesia administered to pregnant women with gestational diabetes mellitus

Background Peridural blockade with lidocaine, bupivacaine, and fentanyl is an anesthetic procedure extensively used in obstetrics, justifying the pharmacokinetic study of these drugs during labor. Objective To investigate the influence of the physiopathological changes of gestational diabetes mellitus (GDM) on the pharmacokinetics of lidocaine and its metabolite monoethylglycinexylidide (MEGX) in pregnant women subjected to peridural anesthesia. Patients and methods Ten normal pregnant women (group 1) and six pregnant women with GDM (group 2) were studied, all of them at term. The patients received 200 mg 2% lidocaine hydrochloride without a vasoconstrictor by the peridural locoregional route. Maternal blood samples were collected at predetermined times for the analysis of lidocaine and MEGX by chromatography and pharmacokinetic analysis. Results The median pharmacokinetic parameters of lidocaine for groups 1 and 2 (P <= 0.05), respectively, were as follows: for Cmax 879.11 and 1,145.58 ng/ml, AUC(0-infinity) 256.01 and 455.95 wg min(-1) ml(-1), Cl/f/kg 10.61 and 5.64 ml min(-1) kg(-1), and Vd/f/kg 3.26 and 2.19 L/kg. The median pharmacokinetic parameters of MEGX for groups 1 and 2 (P <= 0.05), respectively, were as follows: for Cmax 82.71 and 141.38 ng/ml, Tmax 44.71 and 193.14 min, t(1/2)alpha 7.64 and 59.77 min, alpha 0.097 and 0.012/min, and AUC(0-infinity) 29.91 and 108.23 mu g min(-1) ml(-1). Conclusion The present data permit us to conclude that the apparent clearance of lidocaine and MEGX was reduced in diabetic patients compared to normal women, suggesting that GDM inhibits the CYP1A2/CYP3A4 isoforms responsible for the metabolism of this drug and its metabolite.

Effect of maternal epidural analgesia on fetal intrapartum oxygen saturation

The use of maternal epidural analgesia in labor may be associated with nonreassuring fetal heart rate (FHR) patterns. Fetal oxygen saturation (FSpO(2)) monitoring may improve assessment of fetal well-being during this time. Mean FSpO(2) values were compared over seven 5-minute epochs: 5 minutes prior to an epidural event (combined insertion of epidural/top-up epidural analgesia and infusion pump bolus), to 30 minutes following the event, including possible effects of maternal position and FHR pattern on FSpO(2) values. Mean FSpO(2) values were significantly different between the 5 minutes prior (49.5%) versus 16-20 minutes (44.3%, p

Expression und funktionelle Relevanz von Zwei-Poren K+-Kanälen der Task-Familie in thalamischen Schaltneutronen

Thalamus, thalamocortical relay neurons, TASK-channels, Two-Pore-K+-channels, HCN-channels, Halothane, Muscarin, Bupivacaine, Spermine, computer modelling

Obstetric analgesia and anesthesia in Switzerland in 2007

Introduction: The last twenty years has witnessed important changes in the field of obstetric analgesia and anesthesia. In 2007, we conducted a survey to obtain information regarding the clinical practice of obstetric anesthesia in our country. The main objective was to ascertain whether recent developments in obstetric anesthesia had been adequately implemented into current clinical practice. Methodology: A confidential questionnaire was sent to 391 identified wiss obstetric anesthetists. The questionnaire included 58 questions on 5 main topics: activity and organization of the obstetric unit, practice of labor analgesia, practice of anesthesia for caesarean section, prevention of aspiration syndrome, and pain treatment after cesarean section. Results: The response rate was 80% (311/391). 66% of the surveyed anesthetists worked in intermediate size obstetric units (500-1500 deliveries per year). An anesthetist was on site 24/24 hours in only 53% of the obstetric units. Epidural labor analgesia with low dose local anesthetics combined with opioids was used by 87% but only 30% used patient controlled epidural analgesia (PCEA). Spinal anesthesia was the first choice for elective and urgent cesarean section for 95% of the responders. Adequate prevention of aspiration syndrome was prescribed by 78%. After cesarean section, a multimodal analgesic regimen was prescribed by 74%. Conclusion: When comparing these results with those of the two previous Swiss surveys [1, 2], it clearly appears that Swiss obstetric anesthetists have progressively adapted their practice to current clinical recommendations. But this survey also revealed some insufficiencies: 1. Of the public health system: a. Insufficient number of obstetric anesthetists on site 24 hours/24. b. Lack of budget in some hospitals to purchase PCEA pumps. 2. Of individual medical practice: a. Frequent excessive dosage of hyperbaric bupivacaine during spinal anesthesia for cesarean section. b. Frequent use of cristalloid preload before spinal anesthesia for cesarean section. c. Frequent systematic use of opioids when inducing general anesthesia for cesarean section. d. Fentanyl as the first choice opioid during induction of general anesthesia for severe preeclampsia. In the future, wider and more systematic information campaigns by the mean of the Swiss Association of Obstetric Anesthesia (SAOA) should be able to correct these points.

Monitoring of sedation during neuroaxial blockade.

Abstract Study objective: The arousal state changes during spinal anesthesia. It is not clear if BIS and others devices could monitor the induced neuroaxial blockade sedation. Our objective was evaluate BIS and entropy values when spinal anesthesia is done. Design: We developed a prospective study. Patients: 40 patients were included in this study, ASA I-III, over 60 years old, undergoing spinal anesthesia, without premedication scheduled for orthopedics procedures. Intervention: Spinal anesthesia was performed with the unseated volunteer in the lateral decubitus position with a 25-gauge Whitacre needle at L2-L3 space, andanesthesia was done with 12 mg of 0.5% hyperbaric bupivacaine. Patients were positioned supine for 5 min after spinal anesthesia. Measurements: Observer’s Assessment of Alertness/Sedation OAA/S, response (RE) and state entropy (SE) and BIS, and standard hemodynamic measures. Main results: Statistical analysis were performed by Wilcoxon test or ANOVA, p<0.05 was considered statistically significant.RE and BIS showed a better correlation with the OAA/S scale values (Pk 0.81 and 0.82) than SE (Pk 0.69). The OAA/S, RE and SE showed significative differences from basal values after 30 min of neuroaxial anesthesia (ANOVA p<0.05). BIS showed differences after 40 min (ANOVA p<0.05). There were no differences between BIS and RE values along the study (ANOVA p>0.05). Conclusions: The spinal anesthesia decreased the cortical activity and these were founded by OAA/S scale and depth anesthetics monitors. OAA/S was a more sensitive value of this induced sedation. BIS and RE showed a better correlation with OAA/S scale than SE.

Patients's satisfaction concerning postoperative analgesia after caesarean section: a comparison of 4 alternative analgesic regimen

Introduction: Different routes of postoperative analgesia may be used after cesarean section: systemic, spinal or epidural [1]. Although the efficacy of these alternative analgesic regimen has already been studied [2, 3], very few studies have compared patients' satisfaction between them. Methodology: After ethical committee acceptation, 100 ASA 1 patients scheduled for an elective cesarean section were randomized in 4 groups. After a standardized spinal anesthesia (hyperbaric bupivacaine 10 mg and fentanyl 20 μg), each group had a different postoperative analgesic regimen: - Group 1: oral paracetamol 4x1 g/24 h, oral ibuprofene 3x600 mg/24 h and subcutaneous morphine on need (0.1 mg/kg 6x/24 h) - Group 2: intrathecal morphine (100 μg) and then same as Group 1 - Group 3: oral paracetamol 4x1 g/24 h, oral ibuprofene 3x600 mg/24 h and PCEA with fentanyl 5 μg/ml epidural solution - Group 4: oral paracetamol 4x1g/24 h, oral ibuprofene 3x600 mg/ 24 h and PCEA with bupivacaine 0.1% and fentanyl 2 μg/ml epidural solution After 48 hours, a specific satisfaction questionnaire was given to all patients which permitted to obtain 2 different scores concerning postoperative analgesia: a global satisfaction score (0-10) and a detailed satisfaction score (5 questions scored 0-10 with a summative score of 0-50). Both scores, expressed as mean ± SD, were compared between the 4 groups with a Kruskall-Wallis test and between each group with a Mann-Whitney test. A P-value <0.05 was considered significant. Results: Satisfaction scores Gr. 1 (n = 25) Gr. 2 (n = 25) Gr. 3 (n = 25) Gr. 4 (n = 25) P-value global (0-10) 8.2 ± 1.2 9.0 ± 1.0 7.8 ± 2.1 6.5 ± 2.5 0.0006 detailed (0-50) 40 ± 6 43 ± 5 38 ± 6 34 ± 8 0.0002 Conclusion: Satisfaction scores were significantly better in patients who received a systemic postoperative analgesia only (Groups 1 and 2) compared to patients who received systemic and epidural postoperative analgesia (Groups 3 and 4). The best scores were achieved with the combination of intrathecal morphine and multimodal systemic analgesia (Group 2) which allowed early ambulation without significant pain. Patients treated with postoperative epidural analgesia with combined local anesthetics and opioids (Group 4) obtained the worse scores (more restrictive nursing with less mobility, frequent asymmetrical block with insufficient analgesia on one side and motor block on the other)

Effective temporary analgesia for severe painful blind eye.

There are various methods of providing pain relief for painful blind eyes. We wish to recommend this effective method of providing temporary analgesia in patients suffering from a severe painful blind eye before undergoing enucleation.