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

GRILLO, Renato; MELO, Nathalie F. S. de; MORAES, Carolina Morales; LIMA, Renata de; MENEZES, Carla M. S.; FERREIRA, Elizabeth Igne; ROSA, Andre Henrique; FRACETO, Leonardo Fernandes
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
704.9106%
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...

A new approach to the granulation of beta-cyclodextrin inclusion complexes

CASTRO, Ana Doris de; SILVA JR., Nelson P.; CURY, Beatriz S. F.; EVANGELISTA, Raul C.; FREITAS, Luis A. P.; GREMIAO, Maria Palmira D.
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
703.1211%
Cyclodextrins (CDs) are annular oligosaccharides containing 6-12 glucose unities joined together by alpha-1,4 bonds. They have a conical-truncated shape with a lipophilic cavity in which different molecules can be included resulting in a stable inclusion complex. The cyclodextrins have been widely applied in pharmaceutical technology with the objective of increasing the solubility, stability and bioavailability of drugs in different pharmaceutical dosage forms, such as tablets. In order to obtain beta-CD tablets, liquid dispersions of drug/beta-CD are usually submitted to different drying processes, like spray-drying, freeze-drying or slow evaporation, being this dry material added to a number of excipients. However, such drying processes can generate particulate materials showing problems of flow and compressibility, needing their conversion into granulates by means of wetting with granulation liquid followed by additional drying. In this work, the main objective was to evaluate the preparation of tablets without the need of this additional drying step. For this purpose an aqueous dispersion containing acetaminophen/beta-CD complex and cornstarch was dried using a spouted bed and the obtained granules were compressed in tablets. Acetaminophen was used as model drug due to its low water solubility and the inexpensive and widely available cornstarch was chosen as excipient. Acetaminophen powder was added into a beta-cyclodextrin solution prepared in distilled water at 70 degrees C. Stirring was kept until this dispersion cooled to room temperature. Then cornstarch was added and the resulting dispersion was dried in spouted bed equipment. This material was compressed into tablets using an Erweka Korsh EKO tablet machine. This innovative approach allowed the tablets preparation process to be carried out with fewer steps and represents a technological reliable strategy to produce beta-cyclodextrin inclusion complexes tablets. (C) 2010 Elsevier By. All rights reserved.

Synthesis and spectral investigation of Al(III) catechin/beta-cyclodextrin and Al(III) quercetin/beta-cyclodextrin inclusion compounds

DIAS, Karina; NIKOLAOU, Sofia; GIOVANI, Wagner F. De
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
710.65734%
Al-catechin/beta-cyclodextrin and Al-quercetin/beta-cyclodextrin (beta-CD) inclusion compounds were synthesized and characterized by IR, UV-vis, H-1 and C-13 NMR and TG and DTA analyses. Because quercetin is sparingly soluble in water, the stability constants of the Al-quercetin/beta-CD and Al-catechin/beta-CD compounds were determined by phase solubility studies. The A(L)-type diagrams indicated the formation of 1:1 inclusion compounds and allowed calculation of the stability constants. The thermodynamic parameters were obtained from the dependence of the stability constants on temperature and results indicated that the formation of the inclusion compounds is an enthalpically driven process. The thermal decomposition of the solid Al-quercetin/beta-CD and Al-catcchin/beta-CD inclusion compounds took place at different stages, compared with the respective precursors, proving that an inclusion complexation process really occurred. (C) 2007 Published by Elsevier B.V.

Host-guest system of 4-nerolidylcatechol in 2-hydroxypropyl-beta-cyclodextrin: preparation, characterization and molecular modeling

SOARES, Lillian Amelia; LEAL, Ana Flavia Vasconcelos Borges; FRACETO, Leonardo Fernandes; MAIA, Elaine Rose; RESCK, Ines Sabioni; KATO, Massuo Jorge; GIL, Eric de Sousa; SOUSA, Aparecido Ribeiro de; CUNHA, Luiz Carlos da; REZENDE, Kennia Rocha
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
702.1932%
The interaction of 4-nerolidylcatechol (4-NRC), a potent antioxidant agent, and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was investigated by the solubility method using Fourier transform infrared (FTIR) methods in addition to UV-Vis, (1)H-nuclear magnetic resonance (NMR) spectroscopy and molecular modeling. The inclusion complexes were prepared using grinding, kneading and freeze-drying methods. According to phase solubility studies in water a B(S)-type diagram was found, displaying a stoichiometry complexation of 2:1 (drug:host) and stability constant of 6494 +/- A 837 M(-1). Stoichiometry was established by the UV spectrophotometer using Job`s plot method and, also confirmed by molecular modeling. Data from (1)H-NMR, and FTIR, experiments also provided formation evidence of an inclusion complex between 4-NRC and HP-beta-CD. 4-NRC complexation indeed led to higher drug solubility and stability which could probably be useful to improve its biological properties and make it available to oral administration and topical formulations.; CNPq; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); SECTEC-GO; SECTEC-GO

Interaction between bradykinin potentiating nonapeptide (BPP9a) and beta-cyclodextrin: A structural and thermodynamic study

Lula, Ivana; De Sousa, Frederico B.; Denadai, Angelo M. L.; de Lima, Guilherme Ferreira; Duarte, Helio Anderson; dos Mares Guia, Thiago R.; Faljoni-Alario, Adelaide; Santoro, Marcelo M.; de Camargo, Antonio C. M.; dos Santos, Robson A. S.; Sinisterra, Rub
Fonte: ELSEVIER SCIENCE BV; AMSTERDAM Publicador: ELSEVIER SCIENCE BV; AMSTERDAM
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
699.8491%
Herein, we demonstrate the physical and chemical characterizations of the supramolecular complex formed between beta-cyclodextrin (beta CD) and bradykinin potentiating nonapeptide (BPP9a), an endogenous toxin found in Bothrops jararaca. Circular dichroism results indicate a conformational change in the BPP9a secondary structure upon its complexation with beta CD. Nuclear magnetic resonance results, mainly from NOESY experiments, and theoretical calculations showed a favorable interaction between the tryptophan residue of BPP9a and the beta CD cavity. Thermodynamic inclusion parameters were investigated by isothermal titration calorimetry, demonstrating that beta CD/BPP9a complex formation is an exothermic process that results in a reduction in entropy. Additionally, in vitro degradation study of BPP9a against trypsin (37 degrees C, pH 7.2) showed higher stability of peptide in presence of beta CD. This beta CD/BPP9a complex, which presents new chemical properties arising from the peptide inclusion process, may be useful as an antihypertensive drug in oral pharmaceutical formulations. (C) 2011 Elsevier B.V. All rights reserved.; Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPMIG); Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPMIG); Fundacao de Amparo a Pesquisa do Estado Sao Paulo (FAPESP); Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); COINFAR Pesquisa e Desenvolvimento Ltda; COINFAR Pesquisa e Desenvolvimento Ltda; NCTNanobiofar (MCTCNPqFAPEMIG); NCT-Nanobiofar (MCT-CNPq-FAPEMIG)

Interaction of p-cymene with beta-cyclodextrin

Serafini, M. R.; Menezes, P. P.; Costa, L. P.; Lima, C. M.; Quintans, L. J., Jr.; Cardoso, J. C.; Matos, J. R.; Soares Sobrinho, J. L.; Grangeiro, S., Jr.; Nunes, P. S.; Bonjadim, L. R.; Araujo, A. A. S.
Fonte: SPRINGER; DORDRECHT Publicador: SPRINGER; DORDRECHT
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
692.1762%
In this investigation, the study of inclusion complexes formation between p-cymene and beta-cyclodextrin using the methods of physical mixture, paste (PC) and slurry (SC), was evaluated. The results of DSC and TG/DTG showed that the products prepared by PC and SC methods were able to incorporate greater amounts of p-cymene, as evidenced by the weight loss of 7.15 and 3.97%, respectively, which occurred between 120 and 270 A degrees C. SEM images showed decreased size of the household, especially in the SC product. The absorption bands in the IR spectrum, characteristic of p-cymene, were also identified in the preparations, indicating the presence of the compound in the complex.

Computational analysis and physico-chemical characterization of an inclusion compound between praziquantel and methyl-beta-cyclodextrin for use as an alternative in the treatment of schistosomiasis

Rodrigues, Stella Gomes; Chaves, Izabel de Souza; Silva de Melo, Nathalie Ferreira; de Jesus, Marcelo Bispo; Fraceto, Leonardo Fernandes; Fernandes, Sergio Antonio; de Paula, Eneida; de Freitas, Matheus Puggina; Alves Pinto, Luciana de Matos
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 19-28
ENG
Relevância na Pesquisa
692.1762%
Schistosomiasis is still an endemic disease in many regions, with 250 million people infected with Schistosoma and about 500,000 deaths per year. Praziquantel (PZQ) is the drug of choice for schistosomiasis treatment, however it is classified as Class II in the Biopharmaceutics Classification System, as its low solubility hinders its performance in biological systems. The use of cyclodextrins is a useful tool to increase the solubility and bioavailability of drugs. The aim of this work was to prepare an inclusion compound of PZQ and methyl-beta-cyclodextrin (MeCD), perform its physico-chemical characterization, and explore its in vitro cytotoxicity. SEM showed a change of the morphological characteristics of PZQ:MeCD crystals, and IR data supported this finding, with changes after interaction with MeCD including effects on the C-H of the aromatic ring, observed at 758 cm(-1). Differential scanning calorimetry measurements revealed that complexation occurred in a 1:1 molar ratio, as evidenced by the lack of a PZQ transition temperature after inclusion into the MeCD cavity. In solution, the PZQ UV spectrum profile in the presence of MeCD was comparable to the PZQ spectrum in a hydrophobic solvent. Phase solubility diagrams showed that there was a 5.5-fold increase in PZQ solubility...

Inclusion complex of piroxicam with beta-cyclodextrin and incorporation in cationic microemulsion. In vitro drug release and in vivo topical anti-inflammatory effect

Dalmora, M. E.; Dalmora, S. L.; Oliveira, Anselmo Gomes de
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 45-55
ENG
Relevância na Pesquisa
692.1762%
Topical formulations of piroxicam were evaluated by determination of their in vitro release and in vivo anti-inflammatory effect. The in vitro release assay demonstrated that the microemulsion (ME) systems provided a reservoir effect for piroxicam release. However, the incorporation of the ME into carboxyvinilic gel provoked a greater reduction in the release of piroxicam than the ME system alone. Anti-inflammatory activity was carried out by the cotton pellet granuloma inhibition bioassay. Topical anti-inflammatory effect of the piroxicam inclusion complex/ME contained in carboxyvinilic gel showed significant inhibition of the inflammation process (36.9%, P < 0.05). Subcutaneous administration of the drug formulations showed a significant effect on the inhibition of inflammation, 68.8 and 70.5%, P <0.05, when the piroxicam was incorporated in ME and in the combined system beta -cyclodextrin (B-CD)/ME, respectively, relative to the buffered piroxicam (42.2%). These results demonstrated that the ME induced prolonged effects, providing inhibition of the inflammation for 9 days after a single dose administration. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Inclusion complex of piroxicam with beta-cyclodextrin and incorporation in hexadecyltrimethylammonium bromide based microemulsion

Dalmora, MEA; Oliveira, Anselmo Gomes de
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 157-164
ENG
Relevância na Pesquisa
699.2652%
The interaction of piroxicam with beta-cyclodextrin (beta-CD), hexadecyltrimethylammonium bromide-based microemulsion (ME), and ME in the presence of beta-CD aimed at the optimization of topical drug delivery was studied. UV-VIS absorption spectra at pH 5.5 were obtained with and without beta-CD and ME. The stability constant (K) values for the piroxicam/beta-CD complex in the pH range 4.5-6.0 varied from 87 to 29 M-1. The cationic microemulsion was characterized by pseudo-ternary phase diagram. The association constant (K-s) of piroxicam/ME was determined using the framework of the pseudophase model. The value of K-s obtained for piroxicam at pH 5.5 was 132 M-1. At the same pH, the value of K-s for the incorporation of piroxicam/beta-CD complex in the ME was 150 M-1. (C) 1999 Elsevier B.V. B.V. All rights reserved.

A new approach to the granulation of beta-cyclodextrin inclusion complexes

de Castro, Ana Doris; Silva, Nelson P.; Cury, Beatriz S. F.; Evangelista, Raul Cesar; Freitas, Luis A. P.; Gremiao, Maria Palmira D.
Fonte: Elsevier B.V. Sa Publicador: Elsevier B.V. Sa
Tipo: Artigo de Revista Científica Formato: 316-321
ENG
Relevância na Pesquisa
703.1211%
Cyclodextrins (CDs) are annular oligosaccharides containing 6-12 glucose unities joined together by alpha-1,4 bonds. They have a conical-truncated shape with a lipophilic cavity in which different molecules can be included resulting in a stable inclusion complex. The cyclodextrins have been widely applied in pharmaceutical technology with the objective of increasing the solubility, stability and bioavailability of drugs in different pharmaceutical dosage forms, such as tablets. In order to obtain beta-CD tablets, liquid dispersions of drug/beta-CD are usually submitted to different drying processes, like spray-drying, freeze-drying or slow evaporation, being this dry material added to a number of excipients. However, such drying processes can generate particulate materials showing problems of flow and compressibility, needing their conversion into granulates by means of wetting with granulation liquid followed by additional drying. In this work, the main objective was to evaluate the preparation of tablets without the need of this additional drying step. For this purpose an aqueous dispersion containing acetaminophen/beta-CD complex and cornstarch was dried using a spouted bed and the obtained granules were compressed in tablets. Acetaminophen was used as model drug due to its low water solubility and the inexpensive and widely available cornstarch was chosen as excipient. Acetaminophen powder was added into a beta-cyclodextrin solution prepared in distilled water at 70 degrees C. Stirring was kept until this dispersion cooled to room temperature. Then cornstarch was added and the resulting dispersion was dried in spouted bed equipment. This material was compressed into tablets using an Erweka Korsh EKO tablet machine. This innovative approach allowed the tablets preparation process to be carried out with fewer steps and represents a technological reliable strategy to produce beta-cyclodextrin inclusion complexes tablets. (C) 2010 Elsevier By. All rights reserved.

Preparation and thermal characterization of inclusion complex of Brazilian green propolis and hydroxypropyl-beta-cyclodextrin

Rocha, Bruno Alves; Rodrigues, Marina Rezende; Pires Bueno, Paula Carolina; de Mello Costa-Machado, Ana Rita; Lima Leite Vaz, Mirela Mara de Oliveira; Nascimento, Andresa Piacezzi; Barud, Hernane Silva; Berretta-Silva, Andresa Aparecida
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 87-94
ENG
Relevância na Pesquisa
696.3839%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); The propolis produced in Southeastern Brazil is known as green propolis (BGP) because of its color and the most important plant source is Baccharis dracunculifolia. Several authors reported biological activities such as anti-ulcer, anti-inflammator, antimutagenic, antifungal/antibacterial, antileishmanial/antiplasmodial for the BGP. For this reason, BGP has been extensively employed in food and beverages, thus helping improve health and preventing diseases. Some authors related that the biological activities of BGP are mostly due to its high levels of prenylated rho-coumaric acids derivatives, mainly artepillin C. The inclusion complex between Brazilian green propolis (BGP) with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was prepared and its characterization was investigated by different analytical techniques (X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetry) and suggesting that propolis was molecularly dispersed in the HP-beta-CD matrix. The increasing solubility of chemical constituents was determined using quantitation methods for total flavonoids and polyphenols. Furthermore, it was developed a method for the quantitation and identification of the main compounds by high-performance liquid chromatography in order to evaluate the increasing water solubility of each constituent in aqueous BGP extract (aromadendrin...

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

Grillo, Renato; de Melo, Nathalie F. S.; Moraes, Carolina Morales; de Lima, Renata; Menezes, Carla M. S.; Ferreira, Elizabeth Igne; Rosa, Andre Henrique; Fraceto, Leonardo Fernandes
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 295-302
ENG
Relevância na Pesquisa
699.8491%
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...

Increasing Doxycycline Hyclate Photostability by Complexation with beta-Cyclodextrin

Kogawa, Ana Carolina; Zoppi, Ariana; Alfredo Quevedo, Mario; Nunes Salgado, Herida Regina; Raquel Longhi, Marcela
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 1209-1217
ENG
Relevância na Pesquisa
696.3839%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Doxycycline hyclate (DOX) is a highly photosensitive drug, a feature that limits the stability of the corresponding dosage forms. The main objectives of this work were the preparation and characterization of an inclusion complex of DOX with beta-cyclodextrin (beta CD) and to investigate if this approach could improve the photostability of the drug. Guest-host interactions were investigated using nuclear magnetic resonance, which were afterwards combined with molecular modeling methods to study the complex formation and its three-dimensional structure was proposed. A freeze-drying method was applied to obtain the complex in the solid state, which was further confirmed by thermal and spectroscopic techniques. To evaluate the complexation effect on DOX integrity, the photostability of the inclusion complex was studied, with a significant decrease in the photodegradation of DOX being found in aqueous solution upon complexation. Finally, the photoprotection produced by the complexation was evaluated by means of an antimicrobial assay. Overall, the presented results suggest that the formulation of DOX complexed with beta CD constitutes an interesting approach for the preparation of pharmaceutical dosage forms of DOX with enhanced stability properties.

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

GRILLO, Renato; MELO, Nathalie F. S. de; MORAES, Carolina Morales; LIMA, Renata de; MENEZES, Carla M. S.; FERREIRA, Elizabeth Igne; ROSA, Andre Henrique; FRACETO, Leonardo Fernandes
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
699.8491%
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...

Complexation of enalapril maleate with beta-cyclodextrin: NMR spectroscopic study in solution

Ali,Syed Mashhood; Maheshwari,Arti; Asmat,Fahmeena; Koketsu,Mamoru
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2006 PT
Relevância na Pesquisa
710.1618%
A detailed NMR (¹H , COSY, ROESY) spectroscopic study of complexation of enalapril maleate with beta-cyclodextrin was carried out. The ¹H NMR spectrum of enalapril maleate confirmed the existence of cis-trans equilibrium in solution, possibly due to hindered rotation along the amide bond. The cis-trans ratio remained almost the same in the presence of beta-cyclodextrin but in one case it was found significantly different which suggests a catalytic role of beta-cyclodextrin in the isomerization. ¹H NMR titration studies confirmed the formation of an enalapril-beta-cyclodextrin inclusion complex as evidenced by chemical shift variations in the proton resonances of both the host and the guest. The stoichiometry of the complex was determined to be 2:1 (guest: host). The mode of penetration of the guest into the beta-cyclodextrin cavity as well as the structure of the complex were established using ROESY spectroscopy.

Influence of beta-cyclodextrin on the properties of norfloxacin form A

Chierentin, Lucas; Garnero, Claudia; Chattah, Ana Karina; Delvadia, Poonam; Karnes, Thomas; Longhi, Marcela Raquel; Salgado, Herida Regina Nunes
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 683-691
ENG
Relevância na Pesquisa
707.5389%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 2010/13335-2; Cyclodextrins are able to form host-guest complexes with hydrophobic molecules to result in the formation of inclusion complexes. The complex formation between norfloxacin form A and beta-cyclodextrin was studied by exploring its structure affinity relationship in an aqueous solution and in the solid state. Kneading, freeze-drying, and physical mixture methods were employed to prepare solid complexes of norfloxacin and beta-cyclodextrin. The solubility of norfloxacin significantly increased upon complexation with beta-cyclodextrin as demonstrated by a solubility isotherm of the AL type along with the results of an intrinsic dissolution study. The complexes were also characterized in the solid stated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffractometry, scanning electron microscopy (SEM), and solid-state nuclear magnetic resonance (ssNMR) spectrometry. The thermal analysis showed that the thermal stability of the drug is enhanced in the presence of beta-cyclodextrin. Finally...

Spectrophotometric and electrochemical study of the inclusion complex between beta-cyclodextrin and furnidipine

Salazar, R.; Squella Serrano, Juan Arturo; Núñez Vergara, Luis J.; Yáñez Soto, Claudia Andrea
Fonte: PERGAMON-ELSEVIER SCIENCE Publicador: PERGAMON-ELSEVIER SCIENCE
Tipo: Artículo de revista
EN
Relevância na Pesquisa
699.2652%
Inclusion complexation between furnidipine (2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-tetrahydrofurfuryl 5-methyl diester), a calcium-channel antagonist, and beta-cyclodextrin (beta-CyD) was studied in aqueous solution by using both spectrophotometric and electrochemical measurements. The phase solubility profile was classified as A(L)-type, indicating the formation of 1: 1 stoichiometric inclusion complex of furnidipine with beta-CyD. Based on the spectrophotometric absorbance's variations, a formation constant value, K-f, of 156M(-1) was determined. Electrochemical measurements using chronocoulometric experiments were used for the determination of the diffusion coefficients. In absence of beta-CyD, a diffusion coefficient value of 4.32 x 10(-6) cm(2) s(-1) was obtained for furnidipine. The addition of beta-CyD produced a decrease of 30% for the diffusion coefficient. Formation of inclusion complexes of furnidipine with beta-CyD was proved to increase more than three times the solubility of furnidipine.

Determination of nitrendipine with beta-cyclodextrin modified carbon paste electrode

Squella Serrano, Juan Arturo; Núñez Vergara, Luis J.; Yáñez Soto, Claudia Andrea
Fonte: WILEY-V C H VERLAG GMBH Publicador: WILEY-V C H VERLAG GMBH
Tipo: Artículo de revista
EN
Relevância na Pesquisa
704.0699%
Carbon paste electrodes modified with beta-cyclodextrin have been investigated for voltammetric determination of nitrendipine. The immobilization of the beta-cyclodextrin on the carbon paste leads to a modification of the electrode surface that causes a significant increase in the peak current of the nitrendipine reduction, probably due to formation of an inclusion complex between beta-cyclodextrin and nitrendipine. This property was used with analytical purpose,,; by developing a stripping differential pulse voltammetric (SDPV) method to determine nitrendipine.

Inclusion compounds of indomethacin with hydroxypropyl-beta-cyclodextrin: dissolution profile and partition coefficient evaluation; Complexos de inclusão de indometacina com hidroxipropil-beta-ciclodextrina: estudos de dissolução e coeficiente de partição

Rama, Ana Cristina Ribeiro; Veiga, Francisco; Figueiredo, Isabel Vitória; Sousa, Adriano; Caramona, Margarida
Fonte: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Artigo Avaliado pelos Pares Formato: application/pdf
Publicado em 01/03/2006 POR
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Indomethacin, a non steroidal anti-inflamatory, is practically water insoluble. Hydroxypropyl-beta-cyclodextrin grants better solubility characteristics to included drugs. Indomethacin's complexation protects from hydrolysis, enhancing solubility and dissolution. The aim is to study the influence of complexation methods, freeze and spray-dryer, on indomethacin dissolution and partition coefficient. Dissolution results show that freeze-dried inclusion complex has a better time needed to dissolve 50% and 90% - 1 and 1.8 minutes then other products. The same happens with percentage of indomethacin dissolved at 5, 30 and 60 minutes - 92.6±1.8%; 98.9±1.2% e 100.01±0.1% and also with dissolution efficiency and dissolution profile. Partition coefficient results with the complexes obtained by both methods corroborate the theory that there are several intervenient strengths on this process and not only drug's free fraction that regulates transport to organic phase, reinforcing the environmental pH significance. With phosphate buffer pH 7.0, variations on transport grade by cyclodextrin addition are very small, showing no significant changes on log P*. With phosphate buffer pH 5.5, although not significant, variations are slightly higher. We can conclude that complexation enhances dissolution capacities of lipophylic drugs without changing the characteristics that give them a good ability for membrane diffusion.; A indometacina...

Aspectos biofarmacêuticos da formulação de medicamentos para neonatos: fundamentos da complexação de indometacina com hidroxipropil-beta-ciclodextrina para tratamento oral do fechamento do canal arterial; Biopharmaceutical aspects of drug formulation for neonatology: rational for indomethacin's complexation with hydroxypropyl-beta-cyclodextrin to treat patent ductus arteriosus

Rama, Ana Cristina Ribeiro; Veiga, Francisco; Figueiredo, Isabel Vitória; Sousa, Adriano; Caramona, Margarida
Fonte: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Artigo Avaliado pelos Pares Formato: application/pdf
Publicado em 01/09/2005 POR
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Pharmacological therapy for newborns is faced on one hand, with an organism characterized by biological differences and functional immaturity with various grades of evolution for the same age, implying changes on the pharmacokinetic and pharmacodinamic medicine profiles. On the other hand, there is the effective need for pharmacotherapy. The "off label" use of medicines is therefore the only thing left to do, having in mind the risk of using therapeutic agents not studied for this special group of people. On this context it has been considered the use of cyclodextrin derivatives like hydroxypropyl-beta-cyclodextrin as an alternative to prepare oral formulations. With this review we intend to evaluate the rational for using indomethacin's complexation with hydroxypropyl-beta-cyclodextrin, to enhance bioavailability and reduce gastric toxicity characteristics, allowing its oral administration to treat patent ductus arteriosus on preterm and full-term newborns.; A terapêutica farmacológica em recém-nascidos confronta-se, por um lado, com um organismo sujeito a marcadas alterações biológicas, resultantes da composição orgânica e da maturação funcional, que decorre a diferentes graus em crianças com a mesma idade, determinando modificações no perfil farmacocinético e farmacodinâmico e...