共查询到20条相似文献,搜索用时 62 毫秒
1.
Dentuto P. L. Castagnolo M. Catucci L. Cosma P. Fini P. Agostiano A. 《Journal of Thermal Analysis and Calorimetry》2004,77(2):437-444
The interactions between Chlorophyllide a (Chlide), a pigment having the same structure of Chl a without the phytilic tail, and two CDs having the same moieties but different cavity size, the hydroxypropyl- β -cyclodextrin
and the hydroxypropyl-γ-cyclodextrin, were studied in aqueous solutions by means of absorption, fluorescence spectroscopy,
circular dichroism and isothermal titration calorimetry. The results obtained indicate that both cyclodextrins are able to
modify the aggregation equilibrium of the pigment favouring the monomeric form.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
S. Sapino M. E. Carlotti R. Cavalli M. Trotta F. Trotta D. Vione 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):451-455
Inclusion complexation between retinol (RET) and two synthetic alkyl carbonates of γ-cyclodextrin (alkyl-γ-CD) derivatives, ethyl-γ-cyclodextrin (E-CD) and octyl-γ-cyclodextrin (O-CD), was investigated by means of different techniques. The complexes were characterized by differential
scanning calorimetry (DSC). Phase solubility studies, according to the method of Higuchi and Connors [1] were used to evaluate the complexation in aqueous solution at room temperature. In the present study inclusion complexes
of retinol with E-CD and with O-CD were prepared to prevent its rapid degradation. In order to investigate the behavior of
retinol under UV light, test of irradiation was performed separately on samples prepared dispersing retinol (0.1% w/w) or
an equivalent amount of retinol/alkyl-γ-CD respectively in hydroxyethylcellulose (HEC) gel and in an O/W emulsion. The stability over time of retinol was also investigated
storing the samples at 40 °C. Moreover retinol permeation through porcine skin has been evaluated employing Franz cells [2]. Retinol solubility was increased in presence of cyclodextrins while DSC analysis suggest that this inclusion agents are
able to interact with retinol. Data for skin accumulation in porcine ear skin showed that alkyl-CDs increase of approximatively
1,5-fold retinol skin accumulation. Studies on the stability showed that both the inclusion complexes considered are able
to increase retinol stability to light exposure and also to heat. 相似文献
3.
R. Patel D. Bhimani J. Patel D. Patel 《Journal of inclusion phenomena and macrocyclic chemistry》2008,60(3-4):241-251
The objectives of this research were to prepare and characterize inclusion complex of Ezetimibe (EZE) with cyclodextrins (β-cyclodextrin
(β-CD) and hydroxypropyl-β-cyclodextrin (HPβ-CD)) and to study the effect of complexation on the dissolution rate of EZE,
a water insoluble drug. Phase solubility curve was classified as A
P
-type for both cyclodextrins, indicating the 2:1 stoichiometric ratio for β-CD–EZE and HPβ-CD – EZE inclusion complexes. The
inclusion complexes in the molar ratio of 2:1 (β-CD–EZE and HPβ-CD–EZE) were prepared by various methods such as kneading,
coevaporation and physical mixing. The molecular behaviors of drug in all samples were characterized by fourier-transform
infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) studies. The results
of these studies indicated that complex prepared by kneading and coevaporation methods showed inclusion of the EZE molecule
into the cyclodextrins cavities. The highest improvement in in-vitro dissolution profiles was observed in complex prepared
with hydroxypropyl-β-cyclodextrin using co-evaporation method. Mean dissolution time and similarity factor indicated significant
difference between the release profiles of EZE from complexes and physical mixtures and from pure EZE. 相似文献
4.
Cheng Yang Gaku Fukuhara Asao Nakamura Yumi Origane Tadashi Mori Takehiko Wada Yoshihisa Inoue 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):433-437
The complexation behavior of 6-amino-6-deoxy-γ-cyclodextrin (CD), 6A,6X-diamino-6A,6X-deoxy-γ-CDs and 3A-amino-3A-deoxy-altro-γ-CD with 2-anthracenecarboxylic acid (AC) was studied by NMR, UV–vis and circular dichroism spectroscopy. These modified γ-CD derivatives were found to form stable 1:2 host-guest ternary complexes with AC in aqueous solution. Compared with native
γ-CD, the primary-face-aminated γ-CDs exhibited remarkably enhanced overall association constants as a result of the additional electrostatic interactions
between the oppositely charged host and guest. In contrast, the ternary complex formation of the secondary-face-aminated γ-CD with AC was hindered. 相似文献
5.
Yoshiyuki Hagiwara Hidetoshi Arima Fumitoshi Hirayama Kaneto Uekama 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(1-2):65-68
For further increase of retention of doxorubicin (DOX) in tumor cells, we prepared the pegylated liposomes entrapping the complex of DOX with γ-cyclodextrin (γ-CyD) (complex-in-liposome), and then examined the physicochemical properties and the in vitro cellular uptake/release, compared with those of pegylated liposomes entrapping DOX alone (DOX-in-liposome). The particle sizes of these liposomes were almost comparable, and the entrapment ratios of both DOX and γ-CyD in liposomes were more than 90%. The release of DOX from liposomes in the fetal calf serum (FCS) was significantly inhibited by entrapment of γ-CyD in the liposomes. The cellular uptake of DOX into Colon-26 cells, a mouse rectal carcinoma cell line, after incubation with these liposomes was almost equivalent. However, the cellular release of DOX from cells in the complex-in-liposome system was markedly slower than that in the DOX-in-liposome system. These results suggest the potential use of liposomes containing the DOX/γ-CyD complex for high retention of DOX in tumor cells. 相似文献
6.
I. V. Terekhova N. A. Obukhova A. V. Agafonov G. I. Kurochkina A. N. Syrtsev M. K. Gratchev 《Russian Chemical Bulletin》2005,54(8):1883-1886
The interaction of ascorbic acid with hydroxypropyl-α- and hydroxypropyl-β-cyclodextrins of different degree of substitution
was studied at 298.15 K and different pH using solution calorimetry. In an aqueous solution, only hydroxypropyl-β-cyclodextrins
form weak molecular complexes with the nonionized form of ascorbic acid. The thermodynamic functions of complex formation
and stability constants of the complexes were calculated. The systems with weak intermolecular interaction without complex
formation were characterized by enthalpic virial coefficients. On the basis of the obtained thermodynamic characteristics
it was shown that the selectivity of complex formation of hydroxypropyl-α- and hydroxypropyl-β-cyclodextrins with ascorbic
acid is determined by the size of the macrocyclic cavity, the presence of the hydroxypropyl substituent, and the medium acidity.
The degree of substitution of hydroxypropyl-β-cyclodextrins exerts no substantial effect on the thermodynamic parameters of
interaction with ascorbic acid.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1828–1831, August, 2005. 相似文献
7.
P. Fini L. Catucci M. Castagnolo P. Cosma V. Pluchinotta A. Agostiano 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):663-668
The interaction of Rose Bengal (RB) with hydroxypropyl-α-cyclodextrin (HP-α-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD) and
hydroxypropyl-γ-cyclodextrin (HP-γ-CD) has been studied in water and in acetate buffer at pH 4.5 by UV–Vis absorption, fluorescence
spectroscopy and Induced Circular Dichroism at 298 K. Evidence of the complex formation between the RB and all HP-CDs have
been obtained both in water and in buffer. Binding constants and stoichiometry of RB/HP-CD complexes in water have been determined
by applying the modified Benesi-Hildebrand equation to the fluorescence measurements. 相似文献
8.
Sulphamethizole-Cyclodextrin-Hydroxy Propylmethyl Cellulose Multicomponent Complexes 总被引:4,自引:0,他引:4
Pose-Vilarnovo B. Rodríguez-Tenreiro Sánchez X Pérez-Marcos M. B. Torres-Labandeira J. J. 《Journal of Thermal Analysis and Calorimetry》2002,68(2):657-667
The effect of cyclodextrin complexation of sulphamethizole (SM) was studied. Two systems were prepared with two cyclodextrin
derivatives, β-cyclodextrin (BCD) and hydroxypropyl-β-cyclodextrin (HPBCD): binary complexes and multicomponent systems (cyclodextrins
and a hydroxylpropylmethyl cellulose K4M). Inclusion complexes were prepared by freeze-drying and characterized by thermal
analysis (DSC) and X-ray diffractometry. The presence of the polymer in the solution increases the effect of cyclodextrins
– specially BCD – on the solubility of SM. In solid state, binary inclusion complexes enhance the dissolution behaviour of
SM but, from the multi-component complexes, the polymer controls the release of the drug.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
M. E. Carlotti S. Sapino R. Cavalli M. Trotta F. Trotta K. Martina 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):445-450
This work deals with the formation of inclusion complexes between cinnamaldehyde and two synthetic alkylcarbonates of γ-cyclodextrin, namely ethylcarbonate-γ-CD and octylcarbonate-γ-CD. Complexation was monitored by phase-solubility studies, by FT-IR spectroscopy and by DSC and TG analysis.
The diffusion of cinnamaldehyde through a cellulose membrane was investigated in the absence and in the presence of each of
the two γ-CD alkylcarbonates. Studies on photostability and stability over time were carried out on different cosmetic formulations
containing pure cinnamaldehyde or an equivalent amount of cinnamaldehyde complexed with the two alkylcarbonates.
Phase-solubility diagrams, DSC, FTIR and TGA analysis suggested the formation of inclusion complexes. The diffusion of cinnamaldehyde
through the cellulose membrane decreased in the presence of the two alkylcarbonates confirming the interaction of this molecule
with the inclusion agents.
Moreover the stability of cinnamaldehyde to light and heat resulted increased by complexing this fragrance material with the
two alkylcarbonates. 相似文献
10.
Brunella Cappello Clelia di Maio Maria Iervolino Agnese Miro 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(3-4):237-244
Investigation on the influence of hydroxypropyl methylcellulose (HPMC) on solubility and dissolution properties of celecoxib/hydroxypropyl-β-cyclodextrin
system was carried out, with the ultimate goal of enhancing the drug bioavailability. 1H-NMR and 13C-NMR spectroscopy were first performed to elucidate the type of interactions between celecoxib (CEL) and hydroxypropyl-β-cyclodextrin
(HP-β-CD). Then, solubility studies in the absence and in the presence of HPMC were carried out in aqueous solution. After
heating in autoclave of CEL/HP-β-CD/HPMC suspensions a synergistic increasing effect on the aqueous solubility of CEL was
observed. In fact, the presence of both HP-β-CD (0.05 M) and HPMC (0.25% w/v) gave rise to a 330-fold CEL solubility increase,
whereas the cyclodextrin alone provided a 34-fold increase. Gibbs free energy values calculated from phase solubility data
were all negative, indicating the spontaneous nature of CEL solubilization, and they decreased in the presence of HPMC, demonstrating
that the solubilization conditions became more favorable. CEL/HP-β-CD and CEL/HP-β-CD/HPMC solid systems (physical mixtures
and coevaporated products) were characterized by differential scanning calorimetry and infrared spectroscopy. Results suggested
that the coevaporation method yields a high degree of amorphous entities and indicated the formation of a CEL/HP-β-CD complex
in the coevaporated products. The positive effect of HPMC is particularly evident when looking at the CEL dissolution rate
from the binary and ternary solid systems. Specifically, the percent of CEL dissolved after 10 min. resulted 84.21% for ternary
coevaporated product and 50.18% for binary coevaporated product with respect to 13.10% for the drug alone. 相似文献
11.
Mariana Voicescu Gabriela Ionita Marilena Vasilescu Aurelia Meghea 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(3-4):217-219
The action of different molar ratios of α, β, γ-cyclodextrin upon the chemiluminescence of the luminol-H2O2 in alkaline buffer Tris-HCl, pH=8.5 has been evidenced. It was found out that α, β, γ- cyclodextrin have an antioxidant capacity, probably due to the free radicals (that are generate in the system) encapsulation in the their cavity. This behaviour depends on α, β, γ-cyclodextrin molar ratio; α-cyclodextrin and γ-cyclodextrin protects more efficiently against free radicals than β-cyclodextrin. These findings could be very important regarding the oxidative stress process. 相似文献
12.
Giampiero Bettinetti Milena Sorrenti Laura Catenacci Franca Ferrari Silvia Rossi Ilaria Salvadeo Paolo Carraro 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):329-332
Triacetyl α-cyclodextrin, triacetyl β-cyclodextrin and triacetyl γ-cyclodextrin were tested as possible hydrophobic carriers
to prolong the release of hydrophilic teicoplanin (TCP). Physical–chemical characterization of individual components, drug-carrier
physical mixtures at 0.5, 0.67 and 0.75 mass fraction of carrier, and the respective interaction products by kneading or evaporative
crystallization under microwave irradiation was carried out using differential scanning calorimetry (DSC) and thermogravimetric
analysis (TGA). In vitro drug release in pH 7.4 phosphate buffer at 37 °C was determined by intrinsic dissolution rate (IDR)
measurements on non disintegrating compressed discs. Solid-state interactions of TCP with triacetyl α-cyclodextrin by evaporative
crystallization and kneading and with triacetyl β-cyclodextrin by evaporative crystallization (probably resulting in carrier
amorphization) were demonstrated. The role of carrier hydrophobicity, carrier mass fraction and preparation method of solid
drug-carrier combinations on solid-state drug-carrier interactions and slowing down of TCP release was assessed. Modulation
of drug release can be achieved using TCP-triacetyl γ-cyclodextrin combinations at 0.5 mass fraction of carrier. 相似文献
13.
V. A. Livshits B. G. Dzikovskii E. A. Samardak M. V. Alfimov 《Russian Chemical Bulletin》2006,55(2):238-246
Inclusion complexes of spin-labeled pyrrolidine-(1) and piperidine-containing (2) indole derivatives with β-cyclodextrin and γ-cyclodextrin (CD) were prepared in the solid phase and studied by ESR in a
wide temperature interval. For all complexes and free spin probes in solvents of different polarity, local environment polarities
of the NO group of the guest molecules were determined from the outer extrema separations in the ESR spectra measured at 77
K. From analysis of the Saturation Transfer (ST) ESR spectra and temperature dependences of linear ESR spectra of the complexes
it follows that both guest molecules in γ-CD undergo rapid librations. The libration amplitude of the p-orbit axis of the
NO group in molecule 2 increases with temperature and reaches about 16° at 333 K. The ESR lineshape of the β-CD complexes depends on the spin probe/β-CD
molar ratio (ρ) even at ρ < 0.01. Lineshape analysis of the spectra recorded at different ρ showed that they consist of two
components, one of them corresponding to strong spin-spin interaction between guest molecules and the other corresponding
to almost absence of this interaction. The spectral components can be attributed to microphases of the complexes and to isolated
complexes in the β-CD matrix, respectively. Simulation of the ST ESR and linear ESR spectra of the magnetically diluted complexes
showed that the guest motion inside the CD cavity is better described by rotational jumps rather than Brownian diffusion in
an orientation potential. In the temperature range 238—333 K, the rotational frequencies of 1 and 2 are in intervals 1.8·107−6·107 s−1 and 4·107−1.3·108 s−1, respectively. The rotation occurs over the whole solid angle. Significant differences in the character of molecular dynamics
in the γ-CD and β-CD complexes can be explained by different stoichiometry, namely, 1: 1 for the former and 2: 1 for the latter
and by different orientation of guest molecules in the complexes. In both cyclodextrins the rotational mobility of molecules
2 is higher than that of 1 owing to intramolecular conformational transitions in the piperidine ring of 2 and steric hindrances produced by the methyl group in 1.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 233—241, February, 2006. 相似文献
14.
Giangiacomo Torri Sabrina Bertini Tania Giavana Marco Guerrini Nadia Puppini Giorgio Zoppetti 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):317-321
The aim of this work is the determination of the molecular association of progesterone (P) with hydroxypropyl-β-cyclodextrin
(HPβCD) in aqueous solution. The stoichiometry and the binding constants of the inclusion complex were calculated using NMR
techniques. 相似文献
15.
F. Taneri T. Güneri Z. Aigner O. Berkesi M. Kata 《Journal of Thermal Analysis and Calorimetry》2004,76(2):471-479
γ-Cyclodextrin and dimethyl-β-cyclodextrin were used as solubilizing agents for a very poorly water-soluble drug, an imidazole
derivative antifungal agent, clotrimazole; with the aim of improving the physicochemical properties of the drug. Solid products
were prepared by physical mixing, kneading, precipitation and spray-drying methods in 1:1 and 1:2 drug:cyclodextrin molar
ratios. Drug interactions were studied by thermoanalytical methods such as DSC, DTA, TG and DTG, X-ray diffractometry and
Fourier transformation-infrared spectroscopy. The results demonstrated the formation of inclusion complexes in some products.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
To determine optical purities of four aromatic 1,2-diol enantiomers synthesized by a Sharpless asymmetric dihydroxylation
(AD) reaction of olefins, a simple and reliable separation method was achieved with high resolution (R
s > 2.2) by capillary zone electrophoresis (CZE) using hydroxypropyl-β-cyclodextrin (HP-β-CD) as chiral selector and borate
combined with methanol additive as background buffer. Furthermore, the developed CZE method was successfully applied to the
determination of enantiomeric excess of the tested enantiomers. RSD values of migration time and peak area fell within 1.0
and 3.8%, respectively. This method allowed for the determination of ee (%) values of targeted isomers as high as 99.6%. Impurities
of undesired isomers could be detected at levels as low as 0.2% in the presence of the targeted isomers. 相似文献
17.
Wojciech Zielenkiewicz Małgorzata Koźbiał Bożenna Golankiewicz Jarosław Poznański 《Journal of Thermal Analysis and Calorimetry》2010,101(2):555-560
Solubilities of tricyclic acyclovir derivatives in buffered aqueous solutions of hydroxypropyl-β-cyclodextrin (HP-β-CD) at
pH 5.5 and 7.0 were determined at 25 and 37 °C. Complexation of these compounds with HP-β-CD resulted in a noticeable increase
of their solubility; nevertheless it was limited to tricyclic derivatives of acyclovir carrying an aryl substituent. Combination
of 1H NMR and DSC techniques demonstrated the existence of inclusion complexes between acyclovir derivatives and HP-β-CD. The
stability constants, estimated using the Higuchi–Connors method, were found in the range of 10–100 M−1. Additionally, the pK
a values at 25 °C and molar extinction coefficients in aqueous buffered solutions were also determined for all studied compounds. 相似文献
18.
Low-dose γ-radiation produces subtle effects on bovine γ-globulin, as revealed by calorimetric investigations carried out
on concentrated aqueous solutions. The irradiation rate used seems below the threshold that allows complete protein denaturation;
the denaturation temperature, Td, remained unaffected; nonetheless, modifications of the shape of the calorimetric signal reveal that other changes, such
as the dissociation of protein oligomers, could take place.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Ganesh S. Jadhav Ashok R. Patel Pradeep R. Vavia Alpeshkumar K. Malde Evans C. Coutinho 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(1-2):261-273
This study aimed to investigate the effect of β-cyclodextrin on aqueous solubility and dissolution rate of valdecoxib and also to get an insight of molecular interactions involved in formation of valdecoxib‐β-cyclodextrin inclusion complex. Phase solubility analysis indicated complex with possible stoichiometry of 1:1 and a stability constant of 234.01 M−1. Thermodynamic studies in water indicated exothermic nature of inclusion complexation.␣Valdecoxib‐β-cyclodextrin complexes (1:1 M) were prepared by kneading method, solution method and␣freeze–drying method. The complex was characterized by differential scanning calorimetry (DSC), powder X-ray diffractometry (P-XRD), Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance␣(1H-NMR) spectroscopy. Molecular modeling was used to help establish the mode of interaction of β-cyclodextrin with valdecoxib. 1H-NMR analysis suggested that the unsubstituted phenyl ring of valdecoxib display favorable interaction with the hydrophobic cavity of β-cyclodextrin, which was confirmed by molecular dynamic simulations. An inclusion complex model has been established for explaining the observed enhancement of solubility of valdecoxib in water by β-cyclodextrin. Dissolution studies in water showed that the valdecoxib in freeze-dried complex dissolved much faster than the uncomplexed drug and physical mixture. This improvement in dissolution rate is attributed to the increased solubility and wettability due to encapsulation along with decreased crystallanity caused by complex formation, which is evident by DSC and P-XRD studies. 相似文献
20.
Carla Caddeo Maria Manconi Donatella Valenti Elena Pini Chiara Sinico 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(3-4):293-300
In this work, we investigated the influence of β-cyclodextrin on the photostability of tretinoin and compared the photo-chemical
stability of tretinoin, either in methanol or complexed with β-cyclodextrin, when exposed both to UV and fluorescent light.
The physico-chemical characterization of tretinoin-β-cyclodextrin complexes, prepared by the freeze-drying process, using
different tretinoin:β-cyclodextrin molar ratios (1:1 and 1:3), was carried out in solution by phase solubility studies, 1H-NMR spectroscopy, and in solid state by infrared spectroscopy (FT-IR); these analyses confirmed the existence of an inclusion
compound. Solubility study results showed that tretinoin solubility was enhanced by inclusion in β-cyclodextrin as a function
of increasing concentrations of β-cyclodextrin in aqueous solution at different pH values (i.e., 3.0, 5.5, and 7.0). Moreover,
the complexation of the tretinoin with β-cyclodextrin effectively protected the photolabile drug and reduced the degradation
of tretinoin induced by UV and fluorescent light, improving its photo-chemical stability in comparison with free drug in methanol.
Indeed, dissolved tretinoin in methanol degraded very quickly and completely, while β-cyclodextrin-included tretinoin decomposition
was delayed and, after 30 days under UV exposure, the percentage of remaining drug was about 20–25% (depending on the tretinoin
concentration). The photodegradation of tretinoin in methanol under fluorescent light was slower: after 5 days of irradiation
it reached a photostationary state and intact tretinoin remained constant (6.6%). In conclusion, the β-cyclodextrin complexation
always led to a reduction of degradation, depending on the tretinoin:β-cyclodextrin molar ratio and on the drug concentration
(0.2 mg/ml or 0.4 mg/ml). 相似文献