Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Infrared spectroscopic study of triacetyl?β?cyclodextrin and its inclusion complex with nicardipine  [PDF]
I. Bratu,F. Veiga,C. Fernandes,A. Hernanz,J. M. Gavira
Spectroscopy: An International Journal , 2004, DOI: 10.1155/2004/727869
Abstract: Infrared spectra of inclusion compounds of triacetyl?β?cyclodextrin with nicardipine hydrochloride were compared and analysed with those corresponding to their physical mixture and the pure compounds, respectively. Different O–H stretching vibrations, assigned to water molecules, were located in the Fourier Transform Infrared (FT?IR) spectra of triacetyl?β?cyclodextrin, and its inclusion complex with nicardipine obtained by spray?drying (SD) method. Water molecules involved in various hydrogen bonds environments change their status during complexation process. Evidences are observed of the formation of the complex especially in the spectral regions of the amino and carbonyl stretching vibrations.
Inclusion complex of S(-) bupivacaine and 2-hydroxypropyl-β-cyclodextrin: study of morphology and cytotoxicity  [cached]
Revista de Ciências Farmacêuticas Básica e Aplicada , 2009,
Abstract: Local anesthetics (LA) belong to a class of pharmacological compounds that attenuate or eliminate pain by binding to the sodium channel of excitable membranes, blocking the influx of sodium ions and the propagation of the nerve impulse. S (-) bupivacaine (S(-) bvc) is a local anesthetic of amino-amide type, widely used in surgery and obstetrics for sustained peripheral and central nerve blockade. This article focuses on the characterization of an inclusion complex of S(-) bvc in 2-hydroxypropyl- -cyclodextrin (HP- -CD). Differential scanning calorimetry, scanning electron microscopy and X-Ray diffraction analysis showed structural changes in the complex. In preliminary toxicity studies, the cell viability tests revealed that the inclusion complex decreased the toxic effect (p<0.001) produced by S(-) bvc. These results suggest that the S(-) bvc:HP- -CD inclusion complex represents a promising agent for the treatment of regional pain. Keywords: S(-) bupivacaine; cyclodextrin; inclusion complex.
Spectrophotometric study of β-cyclodextrin-rosiglitazone maleate inclusion complex and its analytical application  [PDF]
Indresh Jain,Gulshan Bansal
Journal of Pharmaceutical Education and Research , 2010,
Abstract: A spectrophotometric method for accurate determination of rosiglitazone maleate (RGM)-β-cyclodextrin (β-CD)inclusion complex in aqueous solution was developed and validated. Host-guest complex (1:1) formed between β-CD and RGM was characterized through spectral analyses. The concentration of β-CD, pH of the medium,temperature and reaction time were optimized for maximum stability and absorbance of the complex. The method was found linear in the drug concentration range of 2.5-15.0 μg/ml, precise (% RSD <1), sensitive (LOD 1.5 μg/ml) and accurate (recoveries 98.50-100.6%). Finally, the method was applied successfully to thermal and photostability testing of RGM tablets.
A molecular inclusion complex of atenolol with 2-hydroxypropyl-b-cyclodextrin; the production and characterization thereof
Journal of the Serbian Chemical Society , 2007,
Abstract: The molecular inclusion complex of atenolol with 2-hydroxypropyl-b-cy-clodextrin was synthesized using the coprecipitation method. The complex obtained was characterized by FT-IR, 1H NMR, 13C-NMR spectroscopy, as well as by DSC and X-ray diffraction analysis. The DSC analysis confirmed the existence of the com-plex with the endothermic atenolol melting peak at about 155 oC disappearing. The X-ray diffraction patterns of the complex and 2-hydroxypropyl-b-cyclodextrin were very similar, thus confirming the complete inclusion of the atenolol molecule within the cavity of the 2-hydroxypropyl-b-cyclodextrin. The peaks originating from ate-nolol were completely absent in the diffractogram of the complex. 1H-NMR and 13C-NMR spectra showed certain changes in the chemical shifts of protons and C atoms from atenolol and 2-hydroxypropyl-b-cyclodextrin, indicating that a complex had been formed and also which protons participated in the hydrogen bonds which formed the complex. The atenolol solubility in water was improved (254 mg com-plex cm-3, i.e., 37.5 mg atenolol cm-3), and in pH 3 HCl solution (251 mg com-plex cm-3, i.e., 37 mg atenolol cm-3) when compared to pure atenolol, and even when compared to the atenolol complex with b-cyclodextrin. The increased solubility en-sures greater bioavailability of the active component and, due to the low solubility, significantly corrects for the lack of the basic active substance and, simultaneously, increases its overall therapeutic effect, combined with reduced side effects.
Solid state characterization of domperidone: Hydroxypropyl-β-cyclodextrin inclusion complex  [cached]
Ghodke D,Chaulang G,Patil K,Nakhat P
Indian Journal of Pharmaceutical Sciences , 2010,
Abstract: The purpose of the present study was to prepare inclusion complex of domperidone with hydroxylpropyl-β-cyclodextrin in order improved the solubility and hence to increase dissolution of domperidone. An effect of concentration of hydroxylpropyl-β-cyclodextrin on the aqueous solubility of domperidone was determined by phase-solubility method. The aqueous solubility of domperidone increased as a function of hydroxylpropyl-β-cyclodextrin concentration, showing AL type diagram. Solid domperidone/hydroxylpropyl-β-cyclodextrin complex was prepared in ratio 1:1 by ultrasonication and kneading method. Solid state inclusion complex was characterized by FTIR, powder X-ray diffraction and differential-scanning calorimetry techniques. FTIR studies showed intactness of drug in complex whereas powder diffraction studies showed that hydroxylpropyl-β-cyclodextrin complex was amorphous. Solubility studies showed that complexation increased domperidone solubility as compared to pure drug in 0.1M hydrochloric acid and distilled water. Drug content confirms that ultrasonication is one of the efficient methods to prepare inclusion complex. Dissolution data of inclusion complexes also indicated that there is 1.4 folds increase in dissolution as compared to pure drug and was observed in case of inclusion complexes prepared by ultrasonication.
Improvement of Water Solubility of Josamycin by Inclusion Complex with -Cyclodextrin  [PDF]
J. El Harti,Y. Cherrah,A. Bouklouze
ISRN Analytical Chemistry , 2012, DOI: 10.5402/2012/673564
Abstract: Josamycin propionate (JMP) is an antibiotic belonging to the family of macrolide. According to the Biopharmaceutical Classification System (BCS), this compound can be classed in class II, low solubility and high permeability. In order to increase its apparent water solubility, inclusion complexation between Josamycin propionate and γ-cyclodextrin (γ-CD) was studied. UV spectrophotometric method was employed to investigate the phase-solubility profile and the stability constant of the complexation in aqueous medium. Solid state of the binary system prepared by coevaporation (in 50%-50% ethanol/water) has been characterized using powder X-ray diffraction (XRD) and Fourier transformation-infrared spectrometry (FTIR). These techniques indicate that JMP forms an association complex with γ-CD. The shift in the nuclear magnetic resonance spectroscopy (1H NMR) confirms the existence of the inclusion complex. Also the results obtained showed an enhancement of the solubility in water of Josamycin propionate. 1. Introduction Cyclodextrins (CDs) (Figure 1) are macrocyclic oligosaccharides constituted by 6, 7, or 8 D-glucose units forming α-, β- and γ-cyclodextrin, respectively. They have the property of forming inclusion complex with various quest molecules with suitable polarity and dimension because of their special molecular structure/hydrophobic internal cavity and hydrophilic external surface. The most probable binding involves the insertion of the lipophilic portion of the guest molecule into the cavity of the host and displacement of the water molecules located inside the cavity [1–3]. Figure 1: chemical structure of γ-cyclodextrin. The Complexation with cyclodextrins has been widely used to improve the solubility, dissolution rate, stability, bioavailability of poorly water-soluble drugs, and elimination of undesired properties of drug, such as unpleasant odor and taste [4–9]. In our knowledge no study has been reported in the literature which interested to improve solubility of Josamycin propionate. Josamycin propionate (JMP) (Figure 2) is a macrolide antibiotic, produced by Streptomyces narbonensis vary [10–12], characterized by a large lactone ring, a ketone group and a glycosidically linked amino sugar attached to nucleus which explains the basicity of this antibiotic [13]. According to the Biopharmaceutical Classification System (BCS), this compound can be classed in class II, poorly soluble in aqueous medium but permeable [14, 15]. Figure 2: Chemical structure of Josamycin propionate. The aim of this study was to prepare and to characterize inclusion
In Vitro and In Vivo Evaluation of Oxatomide β-Cyclodextrin Inclusion Complex  [PDF]
Fahima M. Hashem,Mohamed Mostafa,Mahmoud Shaker,Mohamed Nasr
Journal of Pharmaceutics , 2013, DOI: 10.1155/2013/629593
Abstract: The objective of this study was to evaluate the influence of oxatomide β-cyclodextrin inclusion complex on the physicochemical properties and bioavailability of the drug. Oxatomide β-cyclodextrin solid complex was prepared with equimolar ratio of both oxatomide and β-cyclodextrin in presence or absence of water soluble polymers using different techniques. The coevaporated complex prepared in presence of PVP-K15 showed a prompt drug release and significantly increased % dissolution efficiency compared to the pure oxatomide. Moreover, the results of bioavailability evaluation of this complex in rabbits compared to commercial drug product indicated a 73.15% increase in the oral bioavailability of oxatomide. In conclusion, inclusion complex of oxatomide with β-cyclodextrin prepared by coevaporation in presence of PVP-K15 not only results in an enhancement of the oxatomide dissolution rate but also improves the bioavailability of oxatomide. 1. Introduction Oxatomide is an antihistaminic drug that has been reported to have applications in the treatment of a number of different types of allergic and other hypersensitivity reactions. These include but are not restricted to the symptomatic treatment of allergic rhinitis and chronic urticaria, the classical nasal and ocular symptoms associated with hay fever, the reduction of the severity of the erythema, and pruritus in cases of chronic urticaria [1, 2]. Although oxatomide has been extensively investigated and approved for the use in the treatment of a broad range of diseases, it still possesses bioavailability limitations and poor dissolution properties that restrict its full clinical use [1]. One of the major current challenges of the pharmaceutical industry is related to strategies that improve the water solubility of drugs [3, 4]. Low solubility can cause low bioavailability or give rise to large fluctuations in the fraction absorbed in humans that can often not be compensated by a high permeability. Furthermore, low solubility may be associated with stability problems and difficulties in developing an acceptable formulation [5]. By improving the drug release profile of these drugs, it is possible to enhance their bioavailability and reduce side effects [6–9]. Cyclodextrins have been utilized extensively in pharmaceutical formulations to enhance oral bioavailability [10]. Cyclodextrins are a family of cyclic oligosaccharides that are composed of α-1, 4-linked glucopyranose subunits. These macrocyclic carbohydrates with lipophilic central cavities and hydrophilic outer surfaces can form complexes with and
Physicochemical Characterization and Cytotoxic Activity Evaluation of Hydroxymethylferrocene:β-Cyclodextrin Inclusion Complex  [PDF]
Rosa Iacovino,Jolanda Valentina Caso,Filomena Rapuano,Agostino Russo,Marina Isidori,Margherita Lavorgna,Gaetano Malgieri,Carla Isernia
Molecules , 2012, DOI: 10.3390/molecules17056056
Abstract: An inclusion complex of hydroxymethylferrocene (FeMeOH) with β-cyclodextrin (β-CD) was prepared in the solid state by different techniques such as physical mixture, coprecipitation, kneading and freeze-drying. The formation of the inclusion complex was confirmed by X-ray Powder Diffractometry and Fourier Transform-Infrared spectroscopy. In aqueous solution, the 1:1 stoichiometry was established by a Job plot. The inclusion complex formation was also investigated by NMR and the stability constant (Kb) of the complex was determined to be 478 M?1, which is in agreement with that obtained with UV-Vis tritation (Kb = 541.3 M?1). The phase solubility study showed a diagram classified as BS type and that the solubility of FeMeOH was slightly increased in the presence of β-CD. Furthermore, utilizing phase solubility diagram data, the Kb was estimated to be equal to 528.0 M?1. The cytotoxic activity of FeMeOH and its complexation product with β-CD was determined using the MTT-assay on MDA-MB-231 cell line, showing that the inclusion complex has a higher capability of inhibiting cell growth compared to that of pure FeMeOH.
Synthesis and Characterization of the Inclusion Complex of β-cyclodextrin and Azomethine  [PDF]
Kavirajaa Pandian Sambasevam,Sharifah Mohamad,Norazilawati Muhamad Sarih,Nor Atiqah Ismail
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms14023671
Abstract: A β-cyclodextrin (β-Cyd) inclusion complex containing azomethine as a guest was prepared by kneading method with aliquot addition of ethanol. The product was characterized by Fourier Transform Infrared (FTIR) spectrometer, 1H Nuclear Magnetic Resonance ( 1H NMR) and Thermogravimetric Analyzer (TGA), which proves the formation of the inclusion complex where the benzyl part of azomethine has been encapsulated by the hydrophobic cavity of β-Cyd. The interaction of β-Cyd and azomethine was also analyzed by means of spectrometry by UV-Vis spectrophotometer to determine the formation constant. The formation constant was calculated by using a modified Benesi-Hildebrand equation at 25 °C. The apparent formation constant obtained was 1.29 × 10 4 L/mol. Besides that, the stoichiometry ratio was also determined to be 1:1 for the inclusion complex of β-Cyd with azomethine.
Liquid Chromatography Study on Atenolol-β-Cyclodextrin Inclusion Complex
Shailesh M. Buha,Girin A. Baxi,Pragnesh N. Dave,Pranav S. Shrivastav
ISRN Analytical Chemistry , 2012, DOI: 10.5402/2012/423572
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.