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Proceedings ArticleDOI: 10.1109/INEC.2010.5424822

Electrochemical impedance sensor for Levobupivacaine using conducting polypyrrole doped with SWCNTs as sensing material

04 Mar 2010-pp 1419-1420
Abstract: An electrochemical impedance method to detect concentrations of the local anesthetics Levobupivacaine was implemented and the concentration could be detected to 1 ppm. Electropolymerized pyrrole to polypyrrole (Ppy) and Carbon nanotube (CNT) was fabricated on gold electrodes and used as sensors. Various concentrations of Levobupivacaine from 1 to 500 ppm were prepared in DI water as the test samples.

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Topics: Polypyrrole (57%)
References
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Journal ArticleDOI: 10.1016/S0952-8180(02)00513-5
Abstract: Study Objective: To compare the onset time and duration of epidural anesthesia, and the quality of postoperative analgesia produced by levobupivacaine, racemic bupivacaine, and ropivacaine. Design: Prospective, randomized, double-blinded study. Setting: Inpatient anesthesia at a University Hospital. Patients: 45 ASA physical status I, II, and III patients, undergoing elective total hip replacement. Interventions: After standard intravenous midazolam premedication and infusion of 500 mL of Ringer's acetate solution, patients were randomly allocated to receive epidural block with 0.5% levobupivacaine (n = 15), 0.5% bupivacaine (n = 15), or 0.5% ropivacaine (n = 15). Postoperatively, after pinprick sensation recovered at T t , a patient-controlled epidural infusion was provided with 0.125% levobupivacaine, 0.125% bupivacaine, or 0.2% ropivacaine, respectively (baseline infusion rate 5 mL/hr; incremental bolus 2 mL, lockout time: 20 min). Intravenous ketoprofen was also available for rescue analgesia if required. Measurements and Main Results: The onset time of sensory block was 31 ± 16 minutes with levobupivacaine, 25 ± 19 minutes with bupivacaine, and 30 ± 24 minutes with ropivacaine (p = 0.98), after a median (range) volume of 15 (10-18) mL in Group Levobupivacaine, 14 (10-18) mL in Group Bupivacaine, and 15 (10-18) mL in Group Ropivacaine ( p = 0.85). Six patients in the ropivacaine group (40%) showed an intraoperative Bromage score p = 0.02). Recovery of pinprick sensation at T t occurred after 214 ± 61 minutes with levobupivacaine, 213 ± 53 minutes with bupivacaine, and 233 ± 34 minutes with ropivacaine ( p = 0.26). A similar degree of pain relief was observed in the three groups without differences in local anesthetic consumption and need for rescue analgesia. Motor blockade progressively resolved without differences among the three groups. Conclusions: Levobupivacaine 0.5% produces an epidural block of similar onset, quality, and duration as the one produced by the same volume of 0.5% bupivacaine, with a motor block deeper than that produced by 0.5% ropivacaine. When prolonging the block for the first 12 hours after surgery with a patient-controlled epidural infusion, 0.125% levobupivacaine provides adequate pain relief after major orthopedic surgery, with similar recovery of motor function as compared with 0.125% bupivacaine and 0.2% ropivacaine.

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Topics: Levobupivacaine (70%), Ropivacaine (69%), Bupivacaine (64%) ...read more

71 Citations


Journal ArticleDOI: 10.1016/J.SNB.2005.01.001
C.P. de Melo1, B.B. Neto1, E.G. de Lima1, L.F.B. de Lira1  +2 moreInstitutions (2)
Abstract: We discuss the use of polymeric blends formed by the controlled growth of doped polypyrrole chains in the interior of films of different dielectric polymers as sensors of the presence of representative examples of volatile organic compounds. The dielectric films (of either (poly(caprolactone), poly(ethylene oxide), poly(methyl-methacrylate), poly(vinyl alcohol), or poly(vinyl-acetate)) containing an appropriate oxidizing agent were prepared atop a conducting glass substrate and the polymerization of polypyrrole was induced through the vapor phase technique, after exposure of the desired matrix to pyrrole vapor. The UV–vis–NIR spectra of the films were used to monitor the increase of their conductive character through the assessment of the intensity of the polaron band characteristic of the doped form of polypyrrole. The change of conductivity upon exposure to the volatile compounds used (methanol, ethanol, carbon tetrachloride and benzene) was adopted as a measure of the corresponding sensitiveness of the films. Differently to the previous case in which doped films of polypyrrole were examined as sensors (when a similar low level of response was found towards apolar compounds), now we have found that some of the blends (PMMA/PPY and PVA/PPY, in special) exhibit a particular sensitiveness to the polarity of the molecule of the vapor tested. We therefore suggest that the simultaneous use of such polypyrrole blends in an arrangement pattern can improve the efficiency of electronic nose devices.

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Topics: Polypyrrole (64%), Vinyl alcohol (52%), Polymer (50%)

65 Citations


Journal ArticleDOI: 10.1016/J.CHROMA.2005.03.071
A. Koehler1, Reinhard Oertel1, Wilhelm Kirch1Institutions (1)
Abstract: A liquid chromatography-tandem mass spectrometric (LC-MS-MS) method with a rapid and simple sample preparation was developed and validated for the simultaneous determination of the local anesthetics bupivacaine, mepivacaine, prilocaine and ropivacaine in human serum. An external calibration was used. The mass spectrometer was operated in the multiple reaction monitoring mode. A good quadratic response over the range of 1.0-200.0 ng/ml was demonstrated. The accuracy for bupivacaine ranged from 93.2 to 105.7%, for mepivacaine from 96.2 to 104.3%, for prilocaine from 94.6 to 105.7% and for ropivacaine from 94.3 to 104.0%, respectively. The limit of quantification was 1.0 ng/ml for all substances. This method is suitable for pharmacokinetic studies.

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Topics: Mepivacaine (55%), Blood serum (54%), Ropivacaine (53%) ...read more

42 Citations


Journal ArticleDOI: 10.1016/S0928-0987(03)00041-1
Annaliisa L Jappinen, Miia Turpeinen1, Hannu Kokki2, Anu Rasi  +3 moreInstitutions (2)
Abstract: We have evaluated the chemical and microbiological stability of sufentanil citrate, levobupivacaine hydrochloride and a mixture in a 0.9% sodium chloride infusion in order to provide background information on the storage of a sufentanil-levobupivacaine mixture in polypropylene (PP) syringes. Chemical assays were performed by HPLC on days 0, 1, 2, 3, 8, 14, 23, 28 and 30 after storage at 4, 21, and 36 degrees C. Microbiological stability was evaluated under aseptic conditions using a laminar air flow station, with a grade A environment and a B background. The samples taken for microbiological analysis were collected immediately after preparation of the solutions and then after 7, 14, 21 and 28 days storage. At 4 degrees C the sufentanil citrate solution was stable for 23 days. At 21 degrees C the sufentanil citrate solution maintained chemical stability for 3 days, but thereafter the concentration of sufentanil decreased 15% from day 3 to day 8. At 36 degrees C a similar decrease was noticed from day 1 to day 3. On the contrary, the levobupivacaine hydrochloride solution maintained chemical stability for 28 days at 4 and 21 degrees C and for 23 days at 36 degrees C. The sufentanil-levobupivacaine mixture maintained chemical stability for 28 days at 4, 21 and 36 degrees C. The sufentanil and levobupivacaine solutions and the mixture studied maintained microbiological stability for 28 days. According to the chemical and microbiological stability studies, the sufentanil-levobupivacaine mixture in PP syringes could be stored for 28 days at 4 and 21 degrees C.

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Topics: Sufentanil Citrate (58%), Sufentanil (52%)

25 Citations


Journal ArticleDOI: 10.1016/J.TETLET.2004.11.039
Abstract: We report herein the first catalytic asymmetric synthesis of levobupivacaine. The key step involves the asymmetric alkylation of N-benzylimine glycinamide (2b).

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22 Citations