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Chen TW, Rajaji U, Chen SM, Muthumariyappan A, Mogren MMA, Jothi Ramalingam R, Hochlaf M. Facile synthesis of copper(II) oxide nanospheres covered on functionalized multiwalled carbon nanotubes modified electrode as rapid electrochemical sensing platform for super-sensitive detection of antibiotic. Ultrason Sonochem 2019; 58:104596. [PMID: 31450358 DOI: 10.1016/j.ultsonch.2019.05.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/07/2019] [Accepted: 05/09/2019] [Indexed: 05/17/2023]
Abstract
Herein, we report a super-active electrocatalyst of copper(II) oxide nanoparticles (CuO NPs) decorated functionalized multiwalled carbon nanotubes (CuO NPs@f-MWCNTs) by the ultrasonic method. The as-synthesized CuO NPs@f-MWCNTs was characterized through the FESEM, XPS, XRD and electrochemical impedance spectroscopy (EIS). The combination of highly active CuO NPs and highly conductive f-MWCNTs film with rapid detection enables this nanohybrid to display excellent electrochemical performance towards anesthesia drug. Furthermore, the hybrid electrocatalyst modified SPCE was developed for the determination of flunitrazepam (FTM) for the first time. FTM is important anesthesia drug with high adverse effect in human body. Benefiting from the synergistic reaction of CuO NPs and f-MWCNTs, this nanohybrid exhibited high sensitivity and specificity towards FTM electro-reduction. The CuO NPs@f-MWCNTs film modified SPCE exhibits outstanding electrochemical activity including excellent reproducibility, wide linear range from 0.05 to 346.6 µM with nanomolar limit of detection for FTM detection. Further, the as-modified CuO NPs@f-MWCNTs/SPCE has been applied to determination of FTM in biological and drug samples with satisfactory recovery results, thereby showing a notable potential for extensive (bio) sensor applications.
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Affiliation(s)
- Tse-Wei Chen
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan; Research and Development Center for Smart Textile Technology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan
| | - Umamaheswari Rajaji
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan
| | - Shen-Ming Chen
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan.
| | - Akilarasan Muthumariyappan
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan
| | - Muneerah Mogren Al Mogren
- Chemistry Department, Faculty of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - R Jothi Ramalingam
- Surfactant Research Chair, Chemistry Department, College of Science, King Saud University, P.O. Box-2455, Riyadh 11451, Saudi Arabia
| | - Majdi Hochlaf
- Laboratoire Modelisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, Universit́ e Paris-Est, ́5 Blvd. Descartes, 77454 Marne-la-Vallee, France
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Mokrab Y, Bavro VN, Mizuguchi K, Todorov NP, Martin IL, Dunn SMJ, Chan SL, Chau PL. Exploring ligand recognition and ion flow in comparative models of the human GABA type A receptor. J Mol Graph Model 2007; 26:760-74. [PMID: 17544304 DOI: 10.1016/j.jmgm.2007.04.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Accepted: 04/29/2007] [Indexed: 11/25/2022]
Abstract
We present two comparative models of the GABA(A) receptor. Model 1 is based on the 4-A resolution structure of the nicotinic acetylcholine receptor from Torpedo marmorata and represents the unliganded receptor. Two agonists, GABA and muscimol, two benzodiazepines, flunitrazepam and alprazolam, together with the general anaesthetic halothane, have been docked to this model. The ion flow is also explored in model 1 by evaluating the interaction energy of a chloride ion as it traverses the extracellular, transmembrane and intracellular domains of the protein. Model 2 differs from model 1 only in the extracellular domain and represents the liganded receptor. Comparison between the two models not only allows us to explore commonalities and differences with comparative models of the nicotinic acetylcholine receptor, but also suggests possible protein sub-domain interactions with the GABA(A) receptor not previously addressed.
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Affiliation(s)
- Younes Mokrab
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
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García DA, Perillo MA. Effects of flunitrazepam on the Lα-HII phase transition of phosphatidylethanolamine using merocyanine 540 as a fluorescent indicator. Colloids Surf B Biointerfaces 2004; 37:61-9. [PMID: 15450310 DOI: 10.1016/j.colsurfb.2004.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2004] [Revised: 01/29/2004] [Accepted: 04/05/2004] [Indexed: 11/25/2022]
Abstract
Previous studies of our group demonstrated that flunitrazepam is a lipophilic drug capable of interacting with membranes through a partition equilibrium phenomenon. Its localization at the phospholipid polar head region could explain the decrease in the size of dipalmitoylphosphatidylcholine (dpPC) vesicles, through a mechanism that involves the increment in the relative volume of this region with a subsequent increase in the vesicle's surface curvature. In the present work, we investigated if flunitrazepam can affect the L(alpha)-H(II) phase transition of phosphatidylethanolamine through a similar mechanism. This study was approached by using merocyanine 540, a dye sensitive to the molecular packing of membrane lipids. A detailed analysis of merocyanine absorption and fluorescence emission and excitation spectra was performed. The results indicated that the fluorescence emitted came mainly from the monomeric form of merocyanine and that it resulted a good indicator of this phase transition, as was previously described. Flunitrazepam did not affect significantly the onset of the phase transition but showed a tendency to diminish the dye fluorescence emission intensity, which could involve a lower partition of merocyanine in the vesicles. Moreover, the results suggest that this drug produced a delay in the completeness of the phase transition and a decrement in the cooperativity of this phenomenon.
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Affiliation(s)
- Daniel A García
- Departamento de Química, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Velez Sarsfield 1611, Córdoba 5016, Argentina
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Sánchez ME, Turina ADV, García DA, Nolan MV, Perillo MA. Surface activity of thymol: implications for an eventual pharmacological activity. Colloids Surf B Biointerfaces 2004; 34:77-86. [PMID: 15261077 DOI: 10.1016/j.colsurfb.2003.11.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2003] [Revised: 09/24/2003] [Accepted: 11/23/2003] [Indexed: 11/18/2022]
Abstract
In the present work, we studied the ability of thymol to affect the organization of model membranes and the activity of an intrinsic membrane protein, the GABA(A) receptor (GABA(A)-R). In this last aspect, we tried to elucidate if the action mechanism of this terpene at the molecular level, involves its binding to the receptor protein, changes in the organization of the receptor molecular environment, or both. The self-aggregation of thymol in water with a critical micellar concentration approximately = 4 microM and its ability to penetrate in monomolecular layers of soybean phosphatidylcholine (sPC) at the air-water interface, even at surface pressures above the equilibrium, lateral pressure of natural bilayers were demonstrated. Thymol affected the self-aggregation of Triton X-100 and the topology of sPC vesicles. It also increased the polarity of the membrane environment sensed by the electrochromic dye merocyanine. A dipolar moment of 1.341 Debye was calculated from its energy-minimized structure. Its effect on the binding of [3H]-flunitrazepam ([3H]-FNZ) to chick brain synaptosomal membranes changed qualitatively from a tendency to the inhibition to a clear activatory regime, up on changing the phase state of the terpene (from a monomeric to a self-aggregated state). Above its CMC, thymol increased the affinity of the binding of [3H]-FNZ (K(d-control)= 2.9, K(d-thymol)= 1.7 nM) without changing the receptor density (B(max-control)= 910, B(max-thymol)= 895 fmol/mg protein). The activatory effect of thymol on the binding of [ [3H]-FNZ was observed even in the presence of the allosteric activator gamma-aminobutyric acid (GABA) at a concentration of maximal activity, and was blocked by the GABA antagonist bicuculline. Changes in the dipolar arrangement and in the molecular packing of GABA(A)-R environment are discussed as possible mediators of the action mechanism of thymol.
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Affiliation(s)
- Mariela E Sánchez
- Biofísica-Química, Departamento de Química, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Vélez Sarsfield 1611, Córdoba 5016, Argentina
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Raud S, Rünkorg K, Veraksits A, Reimets A, Nelovkov A, Abramov U, Matsui T, Bourin M, Volke V, Kõks S, Vasar E. Targeted mutation of CCK2 receptor gene modifies the behavioural effects of diazepam in female mice. Psychopharmacology (Berl) 2003; 168:417-25. [PMID: 12709779 DOI: 10.1007/s00213-003-1453-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2002] [Accepted: 03/04/2003] [Indexed: 10/26/2022]
Abstract
RATIONALE Evidence suggests that GABA and CCK have opposite roles in the regulation of anxiety. OBJECTIVE The aim of the present work was to study diazepam-induced anxiolytic-like action and impairment of motor co-ordination, and the parameters of benzodiazepine receptors in mice lacking CCK2 receptors. METHODS The action of diazepam (0.5-3 mg/kg i.p.) was studied in the elevated plus-maze model of anxiety and rotarod test using mice lacking CCK2 receptors. The parameters of benzodiazepine receptors were analysed using [3H]-flunitrazepam binding. RESULTS In the plus-maze test, the exploratory activity of the homozygous (-/-) mice was significantly higher compared to their wild-type (+/+) littermates. However, the wild-type (+/+) mice displayed higher sensitivity to the anxiolytic-like action of diazepam. Even the lowest dose of diazepam (0.5 mg/kg) induced a significant increase of open arm entries in the wild-type (+/+) mice. A similar effect in the homozygous (-/-) mice was established after the administration of diazepam 1 mg/kg. The highest dose of diazepam (3 mg/kg) caused a prominent anxiolytic-like effect in the wild-type (+/+) mice, whereas in the homozygous (-/-) animals suppression of locomotor activity was evident. The performance of the homozygous (-/-) mice in the rotarod test did not differ from that of the wild-type (+/+) littermates. However, a difference between the wild-type (+/+) and homozygous (-/-) animals became evident after treatment with diazepam. Diazepam (0.5 and 3 mg/kg) induced significantly stronger impairment of motor co-ordination in the homozygous (-/-) mice compared to their wild-type (+/+) littermates. The density of benzodiazepine binding sites was increased in the cerebellum, but not in the cerebral cortex and hippocampus, of the homozygous (-/-) mice. CONCLUSIONS Female mice lacking CCK2 receptors are less anxious than their wild-type (+/+) littermates. The reduced anxiety in homozygous (-/-) mice probably explains why the administration of a higher dose of diazepam is necessary to induce an anxiolytic-like action in these animals. The highest dose of diazepam (3 mg/kg) induced significantly stronger suppression of locomotor activity and impairment of motor co-ordination in the homozygous (-/-) mice compared to the wild-type (+/+) littermates. The increase in the action of diazepam is probably related to the elevated density of benzodiazepine receptors in the cerebellum of homozygous (-/-) mice. The present study seems to be in favour of increased tone of the GABAergic system in mice without CCK2 receptors.
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Affiliation(s)
- Sirli Raud
- Department of Physiology, Biomedicum, University of Tartu, 19 Ravila Street, 50411 Tartu, Estonia
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Terada M, Masui S, Hayashi T, Watanabe R, Inoue H, Iino M, Nakatome M, Matoba R, Shinozuka T, Murai T, Tanaka E, Honda K. Simultaneous determination of flunitrazepam and 7-aminoflunitrazepam in human serum by ion trap gas chromatography-tandem mass spectrometry. Leg Med (Tokyo) 2003; 5 Suppl 1:S96-S100. [PMID: 12935562 DOI: 10.1016/s1344-6223(02)00075-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A method for the determination of flunitrazepam (FNZ) and 7-aminoflunitrazepam (7-AFNZ) in human serum was developed with ion trap gas chromatography (GC)-tandem mass spectrometry. The 7-AFNZ was derivatizated with 50 microl trifluoroacetic anhydride (TFAA), 60 degrees C-20 min. EI mass spectra and tandem mass spectra of FNZ and 7-AFNZ-TFA were m/z 238, 239, 266, 286, 294, 312, 313(M(+)), m/z 350, 351, 360, 378, 379(M(+)), m/z 238, 239, 240 (precursor ion m/z 286, collision energy 1.5 V), and m/z 239, 254, 264, 336 (precursor ion m/z 351, collision energy 1.8 V), respectively. The detection limits of full scan EI mass spectrometry and tandem mass spectrometry for FNZ and 7-AFNZ in human serum were ca. 200 ng/ml, 60 ng/ml, 15 ng/ml and 1 ng/ml, respectively.
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Affiliation(s)
- Masaru Terada
- Course of Social Medicine, Department of Legal Medicine, Osaka University Graduate School of Medicine F3, Suita-shi, Osaka 565-0871, Japan.
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Ahrens B, Rochholz G, Westphal F, Schütz HW, Ritz-Timme S. [Fatal outcome of poisoning with the benzodiazepines flunitrazepam and diazepam]. Arch Kriminol 2002; 209:95-101. [PMID: 12043441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
On a wintry day a 29-year-old woman was found dead beside her car showing head injuries and signs of hypothermia. Several empty packets of sedative and hypnotic drugs were lying inside the car. Toxicological analysis revealed the presence of flunitrazepam (heart blood of the left and right chamber 0.033 mg/L each), norflunitrazepam (left heart blood 0.029 mg/L, right heart blood 0.027 mg/L), 7-amino-flunitrazepam (left heart blood 0.090 mg/L, right heart blood 0.104 mg/L), diazepam (left heart blood 0.395 mg/L, right heart blood 0.386 mg/L), nordazepam (left heart blood 0.112 mg/L, right heart blood 0.115 mg/L) and temazepam (left heart blood 0.034 mg/L, right heart blood 0.033 mg/L). Neither alcohol nor other drugs were found. It was concluded that benzodiazepine intake led to a disturbance of consciousness. Whether the woman died in this situation due to the icy temperature as a result of hypothermia or whether she died or would have died solely due to benzodiazepine overdosage could not be clarified.
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Affiliation(s)
- Björn Ahrens
- Institut für Rechtsmedizin, Universitätsklinikums Kiel
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8
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Abstract
The effect of molecular packing on flunitrazepam's ability to interact with bio-membranes was studied using dipalmitoylphosphatidylcholine monomolecular layers at the air-water interface as a model membrane. Flunitrazepam penetrated from the subphase into monolayers at lateral pressures below 44.8 mN/m and induced their concentration-dependent expansion. As inferred from the values of compressibility modulus, the elasticity of the liquid-condensed phase decreased in the presence of flunitrazepam. Although this drug hardly penetrated into high-packed monolayers, it was easily incorporated in the low-packed ones at an extent sufficient to reach the partition equilibrium. Below a molecular area of 75 A(2), contrary to what would be expected, the drug surface concentration increased as a function of surface pressure, suggesting that after its penetration in disordered phases, it became energetically or physically trapped in newly-formed liquid condensed clusters. The phenomenon of flunitrazepam penetration and release would have different energy barriers depending on the membrane phase-state.
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Affiliation(s)
- Daniel A García
- Cátedra de Biofísica-Química, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Velez Sarsfield 299 (5000), Córdoba, Argentina
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Claffey DJ, Stout PR, Ruth JA. 3H-nicotine, 3H-flunitrazepam, and 3H-cocaine incorporation into melanin: a model for the examination of drug-melanin interactions. J Anal Toxicol 2001; 25:607-11. [PMID: 11599608 DOI: 10.1093/jat/25.7.607] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To explore drug-melanin interactions, we examined the in vitro tyrosinase-mediated formation of melanin from tyrosine in the presence of the 3H-cocaine (3H-COC), 3H-flunitrazepam (3H-FLU), and 3H-nicotine (3H-NIC) at 10-100,000 ng/mL. Polymerization in the presence of 10 or 100 ng/mL of each drug resulted in almost complete drug incorporation into the melanin pellet. Only 12% (3H-NIC) to 28% (3H-FLU) of the pellet-associated radioactivity could be released upon treatment with 6 M HCl. At 1000-100,000 ng/mL, between 20 and 50% of label became melanin-associated. In each case a significant percentage of melanin-associated radioactivity was resistant to treatment with 6 M HCl. Nicotine-associated radioactivity in the polymer was subject to much greater quenching than was 3H-COC or 3H-FLU, suggesting a much tighter association with the melanin. The subsequent demonstration of a covalent adduct of a melanin intermediate and nicotine has demonstrated the utility of this polymerization system as a model for further chemical characterization of drug-melanin interactions.
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Affiliation(s)
- D J Claffey
- University of Colorado Health Sciences Center, Molecular Toxicology and Environmental Health Sciences, Denver 80262, USA
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Chuang VT, Otagiri M. Flunitrazepam, a 7-nitro-1,4-benzodiazepine that is unable to bind to the indole-benzodiazepine site of human serum albumin. Biochim Biophys Acta 2001; 1546:337-45. [PMID: 11295439 DOI: 10.1016/s0167-4838(01)00151-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Benzodiazepine (BDZ) is generally thought to bind to site II of human serum albumin (HSA), also known as the indole-BDZ site, which is located at subdomain III A of the molecule. However, differences in the binding characteristics of BDZ drugs with HSA have been reported. The photolabeling profiles of HSA with [(3)H]flunitrazepam (FNZP) in the presence and absence of diazepam (DZP) were shown to be identical, suggesting that each drug primarily binds to different regions. The results of fluorescent probe displacement experiments showed that FNZP failed to decrease the fluorescence of dansylsarcosine to an extent similar to that of DZP. In the photoinhibition experiment, site I and site II ligands failed to inhibit the photoincorporation of [(3)H]FNZP to HSA. In order to evaluate the photolabeling specificity of FNZP, an attempt was made to photolabel alpha(1)-acid glycoprotein (AGP) which also binds BDZ with similar affinity as HSA. The effect of myristate (MYR) and DZP on the FNZP photolabeling of these two major drug binding plasma proteins was examined. Photoincorporation was inhibited when HSA was photolabeled with [(3)H]FNZP in the presence of MYR but not in the presence of DZP. Conversely, DZP inhibited the photolabeling of [(3)H]FNZP to AGP. These results suggest that FNZP interacts with HSA at regions which are not located in the preformed binding pocket of subdomain III A.
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Affiliation(s)
- V T Chuang
- Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, 862-0973, Kumamoto, Japan
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Abstract
An alarming increase in the misuse/abuse of nitrobenzodiazepine derivatives, especially flunitrazepam, prompted us to establish reliable analytical protocols for their routine detection. Whilst the parent drugs are readily available from a number of commercial sources, it was found difficult to obtain samples of the corresponding amino metabolites which were required as analytical standards. This lead us to develop the straightforward synthetic protocol described here, to convert the readily available parent drugs, namely flunitrazepam and nitrazepam, to their respective 7-amino derivatives. The method requires minimum laboratory facilities. It involves the reduction of the nitro functionality in the parent drug to an amino group using tin (II) chloride under mild conditions, using ultrasonication at room temperature. The method is simple and should give toxicology laboratories better access to these much needed compounds.
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Affiliation(s)
- J Feely
- Department of Pharmacology and Therapeutics, Trinity College, Dublin 2
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Abstract
The purpose of this research was to investigate the influence of surfactants on the dissolution of benzodiazepines in interactive mixtures. The dissolution of ternary interactive mixtures consisting of micronized drugs (oxazepam, nitrazepam, and flunitrazepam) and micronized surfactants (sodium lauryl sulfate and cetrimide) adhered onto the surface of a lactose carrier (250-355 microm) was studied using the USP/NF paddle method. Dissolution was considered to occur from dispersed particle and aggregate fractions of the drugs, and data were modeled using multiexponential equations. The initial concentrations of the aggregates and dissolution rate constants were estimated using a Marquardt-Levenberg nonlinear least squares algorithm. The marked increase in dissolution rate which occurred with increasing concentrations of sodium lauryl sulfate and cetrimide resulted both from deaggregation of the benzodiazepine particles and from increases in the dissolution rate constants of the dispersed particle and aggregate fractions probably associated with an increased intrinsic dissolution rate. The presence of 5% sodium lauryl sulfate in the interactive mixture reduced the initial percent of aggregates from about 85% in a binary mixture to less than 10% and about doubled the dispersed particle dissolution rate constant. The presence of the surfactant in the surface particulate matrix of the interactive mixture was essential for its deaggregation effect. Sodium lauryl sulfate was more effective than cetrimide in achieving drug deaggregation.
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Affiliation(s)
- J Liu
- Department of Pharmaceutics, Victorian College of Pharmacy, Monash University, Parkville, Australia
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Abstract
The use of gel filtration chromatography with Sephadex as a separation medium was used in order to study flunitrazepam (FNTZ) partitioning into artificial model membranes consisting of dipalmitoyl-phosphatidylcholine (dpPC) vesicles, under controlled temperature conditions. In this system two phenomena are taking place simultaneously: the ligand-liposome interaction and the lipid self-aggregation to form the liposome. The liposome-FNTZ interaction was evidenced by the non-enantiography of the first derivative of FNTZ elution peak in frontal chromatography through Sephadex G-75. On the other hand, the presence of FNTZ reduced liposomes mean size and increased their size dispersion as evidenced by molecular filtration through Sephadex G-200. The dpPC-buffer FNTZ partition coefficient determined in zonal chromatography through Sephadex G-10 increased about 33% when the temperature rose above the temperature of dpPC transition from the liquid crystalline to the fluid phase. Gel filtration chromatography seems a suitable technique to study lipid liposome-FNTZ interactions at a qualitative level. In addition, this technique has the advantage over other methods of giving the possibility of observing the mutual effects exerted between the drug and the self-aggregating structure.
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Affiliation(s)
- D A García
- Cátedra de Química Biológica, Facultad de Ciencias Exactas, Físicas y Naturales, Córdoba, Argentina
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Berthault F, Kintz P, Mangin P. Simultaneous high-performance liquid chromatographic analysis of flunitrazepam and four metabolites in serum. J Chromatogr B Biomed Appl 1996; 685:383-7. [PMID: 8953185 DOI: 10.1016/s0378-4347(96)00220-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A high-performance liquid chromatographic method for the simultaneous determination of flunitrazepam and four metabolites, desmethylflunitrazepam (DMF), 7-aminodesmethylflunitrazepam (7-NH2DMF), 7-aminoflunitrazepam (7-NH2F) and 3-hydroxyflunitrazepam (3-OHF), in serum is described. The method involves a simple extraction from alkalinized plasma (pH 9.5) into diethyl ether-chloroform (80:20, v/v). Prazepam was used as an internal standard for the quantification of the five compounds. Separation was achieved with a 10 microns RSil CN column (300 x 3.9 mn I.D.). The detection wavelength was set at 242 nm. The limits of detection ranged from 2.5 to 5 micrograms/l with a limit of quantification of 10 micrograms/l for all analytes.
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Affiliation(s)
- F Berthault
- Institute of Legal Medecine, Strasbourg, France
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Zhang L, Tardy M, Berry JP, Escaig F, Galle P. [Localization of two neurotropic molecules in cultured glial cells by ion microscopy]. C R Acad Sci III 1992; 314:55-60. [PMID: 1348447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
The intracellular localization of two families of neurotropic drugs: flunitrazepam and flurazepam (benzodiazepine), triflupromazine and trifluoperazine (phenothiazine) has been studied by ion microscopy. The molecules have been incubated with C6 glioblastoma cells from rat origin and with astroglial primary cultures. The images of the intracellular distributions of the two drugs are easily obtained by selecting the fluorine atom of the molecules. The images obtained show that flunitrazepam and flurazepam, two drugs of the benzodiazepine group are mainly located to the nuclei, whereas triflupromazine and trifluoperazine, two phenothiazines are exclusively located inside the cytoplasm.
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Affiliation(s)
- L Zhang
- SC 27 I.N.S.E.R.M., Faculté de Médecine, Créteil
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Moro ME, Novillo-Fertrell J, Velazquez MM, Rodriguez LJ. Kinetics of the acid hydrolysis of diazepam, bromazepam, and flunitrazepam in aqueous and micellar systems. J Pharm Sci 1991; 80:459-68. [PMID: 1880727 DOI: 10.1002/jps.2600800513] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A kinetic study of the acid hydrolysis of aqueous diazepam, bromazepam, and flunitrazepam was carried out at 25 degrees C using a spectrophotometric method. For diazepam and flunitrazepam, the experimental pseudo first-order rate constant decreased as the acid concentration was increased. The contrary behavior was found in the case of bromazepam. A kinetic scheme that includes the hydrolysis reaction of both protonated and nonprotonated species of the drug can account for these results. Also, the kinetics of the acid hydrolysis of the same drugs in the presence of micellar aggregates [nonionic polyoxyethylene-23-dodecanol (Brij 35); cationic cetyl trymethyl ammonium bromide (CTAB); and anionic sodium decyl (SdeS), dodecyl (SDS), and tetradecyl (STS) sulfate] was studied at 25 degrees C. Negligible effects were observed in the cases of nonionic and cationic micelles. Anionic micelles produced an inhibitory effect in the reaction velocity. This effect increased as the hydrophobic nature of the surfactant increased. All these facts are interpreted quantitatively by means of a pseudophase model.
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Affiliation(s)
- M E Moro
- Departamento de Química física, Facultad de Farmacia, Universidad de Salamanca, Spain
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Abstract
The partition coefficient (P) of a benzodiazepine, flunitrazepam (FNTZ), was determined in a synaptosomal membrane/buffer system. A two component model was used, one of the components reflecting the drug partitioning into the membrane, and the other the amount of drug in the aqueous phase retained by the pellet after the centrifugation. The quantity of [3H]FTNZ measured as nonspecifically bound to the membrane includes both components so, the second one had to be discounted and in order to determined its magnitude a parallel experiment was performed using a non-partitioning hydrophilic drug (gamma-[3H]aminobutyric acid, [3H]GABA). The assay required previous determination of the fraction of the total volume of the incubation system that corresponded to membrane (fm). The fm value was calculated from the density value (delta) determined by a picnometer method. The results obtained were: delta = 1.66 +/- 0.02; fm = (1.6 +/- 0.2) 10(-3); P = 18.5 +/- 0.8. This P value could explain nonspecific effects of BZDs on some functions of the neuronal membrane.
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Affiliation(s)
- M A Perillo
- Cátedra de Química Biológica, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba, Argentina
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