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58. Isoxazoles V: Chemical Stability of Diisoxazolylnaphthoquinone in Aqueous Solution

Author

Longhi, Marcela R., De Bertorello, Maria M., and Briñon, Margarita C.

Abstract

The hydrolytic degradation of 2-(3,4-dimethyl-5-isoxazolylamine)-N-(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinone-4-imine (1) was investigated over a wide range of pH values and at different temperatures. The degradation rates were determined by reversed-phase HPLC and were observed to follow pseudo-first-order kinetics with respect to the concentration of 1. The pH–rate profile was linear with slopes – 1 and + 1 in acid and alkaline pH, respectively, becoming pH independent in the region of maximum stability from pH 4.5 to 10.0. Neither primary salt effects nor buffer catalysis was observed due to the buffer species employed.

Published
1989
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59. Complejos binarios y ternarios de fármacos hidrofóbicos modelo incorporados a sistemas nanoestructurados : caracterización fisicoquímica y biofarmacéutica

Author

Aloisio, Carolina [UNESP], Longhi, Marcela Raquel, Gomes de Oliveira, Anselmo, Palma, Santiago Daniel, Bujan de Vargas, Elba Inés, Daflón Gramião, Palmira, Universidade Estadual Paulista (Unesp), Oliveira, Anselmo Gomes de [UNESP], and Longhi, Marcela R. [UNESP]

Subjects
Nanocompuestos, Tecnologia farmacêutica, Evaluación de medicamentos, Pharmaceutical technology, Lipossomos, Sistemas de liberación de medicamentos, Preparaciones farmacéuticas, Fármacos, Nanomedicina, Medicamentos, Química medicinal, Solubilidad, Antibióticos, Ciclodextrinas
Abstract

Made available in DSpace on 2015-04-09T12:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-15Bitstream added on 2015-04-09T12:48:20Z : No. of bitstreams: 1 000816490_20200401.pdf: 124722 bytes, checksum: 70e72ef360378a6450760457b5d1b1f0 (MD5) Made available in DSpace on 2015-04-09T12:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-15Bitstream added on 2015-04-09T12:48:20Z : No. of bitstreams: 1 000816490_20200401.pdf: 124722 bytes, checksum: 70e72ef360378a6450760457b5d1b1f0 (MD5). Added 1 bitstream(s) on 2020-06-17T16:35:56Z : No. of bitstreams: 1 000816490.pdf: 4468936 bytes, checksum: 685bae0dbc1db3ea4d290a1e6a25251a (MD5) Made available in DSpace on 2015-04-09T12:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-15Bitstream added on 2015-04-09T12:48:20Z : No. of bitstreams: 1 000816490_20200401.pdf: 124722 bytes, checksum: 70e72ef360378a6450760457b5d1b1f0 (MD5) Bitstreams deleted on 2020-06-17T16:34:58Z: 000816490_20200401.pdf, Made available in DSpace on 2015-04-09T12:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-15Bitstream added on 2015-04-09T12:48:20Z : No. of bitstreams: 1 000816490_20200401.pdf: 124722 bytes, checksum: 70e72ef360378a6450760457b5d1b1f0 (MD5) Bitstreams deleted on 2020-06-17T16:34:58Z: 000816490_20200401.pdf, Made available in DSpace on 2015-04-09T12:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-15Bitstream added on 2015-04-09T12:48:20Z : No. of bitstreams: 1 000816490_20200401.pdf: 124722 bytes, checksum: 70e72ef360378a6450760457b5d1b1f0 (MD5) Bitstreams deleted on 2020-06-17T16:34:58Z: 000816490_20200401.pdf, Made available in DSpace on 2015-04-09T12:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-15Bitstream added on 2015-04-09T12:48:20Z : No. of bitstreams: 1 000816490_20200401.pdf: 124722 bytes, checksum: 70e72ef360378a6450760457b5d1b1f0 (MD5) Bitstreams deleted on 2020-06-17T16:34:58Z: 000816490_20200401.pdf, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Published
2014

60. Triethanolamine stabilization of methotrexate-β-cyclodextrin interactions in ternary complexes.

Author

Barbosa JA, Zoppi A, Quevedo MA, de Melo PN, de Medeiros AS, Streck L, de Oliveira AR, Fernandes-Pedrosa MF, Longhi MR, and da Silva-Júnior AA

Subjects
Calorimetry, Differential Scanning, Crystallography, X-Ray, Drug Carriers, Freeze Drying, Hydrophobic and Hydrophilic Interactions, Methotrexate administration & dosage, Molecular Docking Simulation, Molecular Dynamics Simulation, Solubility, Spectroscopy, Fourier Transform Infrared, Static Electricity, Thermogravimetry, Water, Ethanolamines pharmacology, Excipients chemistry, Methotrexate chemistry, beta-Cyclodextrins chemistry
Abstract

The interaction of methotrexate (MTX) with beta-cyclodextrin (β-CD) in the presence of triethanolamine (TEA) was investigated with the aim to elucidate the mechanism whereby self-assembly cyclodextrin systems work in association with this third component. Solubility diagram studies showed synergic increment of the MTX solubility to be about thirty-fold. Experiments using 2D ROESY and molecular modeling studies revealed the inclusion of aromatic ring III of the drug into β-CD cavity, in which TEA contributes by intensifying MTX interaction with β-CD and stabilizes MTX:β-CD:TEA ternary complex by electrostatic interaction. The maintenance of these interactions in solid phase was also studied in ternary MTX:β-CD:TEA and comparisons were made with freeze dried binary MTX:β-CD and physical mixtures. FTIR studies evidenced that MTX-β-CD interaction remained in solid ternary complexes, which was also supported by thermal (differential scanning calorimetry (DSC), thermogravimetric analysis (TG)/first derivative of TG analysis (DTG) and C,N,H elementary analysis) and structural (X-ray diffraction analysis, (XRD)) studies, mainly regarding the increment of drug stability. The efficient in vitro drug dissolution studies successfully demonstrated the contribution of ternary complexes, which highlights the importance of this possible new raw material for further applications in drug delivery systems.

Published
2014
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61. Ternary complexes of flurbiprofen with HP-beta-CD and ethanolamines characterization and transdermal delivery.

Author

Maitre MM, Longhi MR, and Granero GG

Subjects
2-Hydroxypropyl-beta-cyclodextrin, Administration, Cutaneous, Anti-Inflammatory Agents, Non-Steroidal pharmacokinetics, Ethanolamines pharmacology, Flurbiprofen pharmacokinetics, Humans, Solubility, Spectroscopy, Fourier Transform Infrared, beta-Cyclodextrins pharmacology, Anti-Inflammatory Agents, Non-Steroidal chemistry, Ethanolamines chemistry, Flurbiprofen chemistry, Skin Absorption drug effects, beta-Cyclodextrins chemistry
Abstract

Binary and multicomponent systems complexes prepared with HP-beta-CD and/or with monoethanolamine (MEA), diethanolamine (DEA) or triethanolamine (TEA) were obtained. The results of solid-state studies indicated the presence of strong interactions between the components in the binary and the ternary systems. Drug solubility and dissolution rate in water were notably improved by employing the HP-beta-CD and the alkanolamines. The combined use of cosolvency and complexation with MEA in the presence of HP-beta-CD on the permeation of flurbiprofen through the human skin was evaluated. The combination of IPM, PG, and HP-beta-CD yield the highest permeation for the flurbiprofen-MEA complex.

Published
2007
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