共查询到20条相似文献,搜索用时 15 毫秒
1.
Sateeshkumar Sathigari Gurkishan Chadha Y-H. Phillip Lee Nydeia Wright Daniel L. Parsons Vijay K. Rangari Oladiran Fasina R. Jayachandra Babu 《AAPS PharmSciTech》2009,10(1):81-87
Efavirenz (EFV) is an oral antihuman immunodeficiency virus type 1 drug with extremely poor aqueous solubility. Thus, its
gastrointestinal absorption is limited by the dissolution rate of the drug. The objective of this study was to characterize
the inclusion complexes of EFV with β-cyclodextrin (β-CD), hydroxypropyl β-CD (HPβCD), and randomly methylated β-CD (RMβCD)
to improve the solubility and dissolution of EFV. The inclusion complexation of EFV with cyclodextrins in the liquid state
was characterized by phase solubility studies. The solid-state characterization of various EFV and CD systems was performed
by X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy analyses. Dissolution studies were
carried out in distilled water using US Pharmacopeia dissolution rate testing equipment. Phase solubility studies provided
an AL-type solubility diagram for β-CD and AP-type solubility diagram for HPβCD and RMβCD. The phase solubility data enabled calculating stability constants (K
s) for EFV-βCD, EFV-HPβCD, and EFV-RMβCD systems which were 288, 469, and 1,073 M−1, respectively. The physical and kneaded mixtures of EFV with CDs generally provided higher dissolution of EFV as expected.
The dissolution of EFV was substantially higher with HPβCD and RMβCD inclusion complexes prepared by the freeze drying method.
Thus, complexation with HPβCD and RMβCD could possibly improve the dissolution rate-limited absorption of EFV. 相似文献
2.
Stratos Maragos Helen Archontaki Panos Macheras Georgia Valsami 《AAPS PharmSciTech》2009,10(4):1444-1451
Praziquantel (PZQ), the primary drug of choice in the treatment of schistosomiasis, is a highly lipophilic drug that possesses
high permeability and low aqueous solubility and is, therefore, classified as a Class II drug according to the Biopharmaceutics
Classification System (BCS). In this work, β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) were used in order
to determine whether increasing the aqueous solubility of a drug by complexation with CDs, a BCS-Class II compound like PZQ
could behave as BCS-Class I (highly soluble/highly permeable) drug. Phase solubility and the kneading and lyophilization techniques
were used for inclusion complex preparation; solubility was determined by UV spectroscopy. The ability of the water soluble
polymer polyvinylpyrolidone (PVP) to increase the complexation and solubilization efficiency of β-CD and HP-β-CD for PZQ was
examined. Results showed significant improvement of PZQ solubility in the presence of both cyclodextrins but no additional
effect in the presence of PVP. The solubility/dose ratios values of PZQ-cyclodextrin complexes calculated considering the
low (150 mg) and the high dose (600 mg) of PZQ, used in practice, indicate that PZQ complexation with CDs may result in drug
dosage forms that would behave as a BCS-Class I depending on the administered dose. 相似文献
3.
Conclusion An inclusion complex of rofecoxib and HPβ-CD was prepared successfully by the spray-drying method in a molar ratio of 1∶1.
The inclusion complex was found to have improved in vitro drug release compared with the pure drug. The solubility profile
of complexes of rofecoxib prepared using HPβ-CD as the complexing agent in a molar ratio of 1∶1 by the spray-drying method
in pH 1.2 and pH 7.4 indicated that the acid solubility of rofecoxib was enhanced considerably by formation of an inclusion
complex with HPβ-CD. The above results also clearly demonstrated a significant decrease in the gastric ulcerogenic activity
of rofecoxib through complexation with cyclodextrins. Even though the physical mixture of rofecoxib with cyclodextrins reduced
ulcer formation, it was the spray-dried complex formation approach that minimized gastric ulceration. These findings are extremely
important from a commercial point of view as the prepared complex removes a major drawback for rofecoxib in therapy.
Published: September 20, 2005 相似文献
4.
The aim of this work was to study the influence of β-cyclodextrin (β-CD) on the biopharmaceutic properties of diclofenac (DCF).
To this purpose the physicochemical characterization of diclofenac-β-cyclodextrin binary systems was performed both in solution
and solid state. Solid phase characterization was performed using differential scanning calorimetry (DSC), powder x-ray diffractometry
(XRD), and Fourier transform infrared spectroscopy (FTIR). Phase solubility analyses, and in vitro permeation experiments
through a synthetic membrane were performed in solution. Moreover, DCF/β-CD interactions were studied in DMSO by1H nuclear magnetic resonance (NMR) spectroscopy. The effects of different preparation methods and drug-to-β-CD molar ratios
were also evaluated. Phase solubility studies revealed 1∶1 M complexation of DCF when the freeze-drying method was used for
the preparation of the binary system. The true inclusion for the freeze-dried binary system was confirmed by1H NMR spectroscopy, DSC, powder XRD, and IR studies. The dissolution study revealed that the drug dissolution rate was improved
by the presence of CDs and the highest and promptest release was obtained with the freeze-dried binary system. Diffusion experiments
through a silicone membrane showed that DCF diffusion was higher from the saturated drug solution (control) than the freeze-dried
inclusion complexes, prepared using different DCF-β-CD molar ratios. However, the presence of the inclusion complex was able
to stabilize the system giving rise to a more regular diffusion profile.
Published: October 22, 2005 相似文献
5.
Doile MM Fortunato KA Schmücker IC Schucko SK Silva MA Rodrigues PO 《AAPS PharmSciTech》2008,9(1):314-321
Inclusion complexes between dexamethasone acetate (DMA), a poorly water soluble drug, and β-cyclodextrin (βCD) were obtained
to improve the solubility and dissolution rate of this drug. Phase-solubility profile indicated that the solubility of DMA
was significantly increased in the presence of βCD (33-fold) and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Solid complexes prepared by different methods (kneading, coevaporation,
freeze drying) and physical mixture were characterized by differential scanning calorimetry, thermogravimetry, infrared absorption
and optical microscopy. Preparation methods influenced the physicochemical properties of the products. The dissolution profiles
of solid complexes were determined and compared with those DMA alone and their physical mixture, in three different mediums:
simulated gastric fluid (pH 1.2), simulated intestinal fluid (pH 7.4) and distilled water. The dissolution studies showed
that in all mediums DMA presented an incomplete dissolution even in four hours. In contrast, the complexes formed presented
a higher dissolution rate in simulated gastric fluid (SGF pH 1.2), which indicate that these have different ionization characteristics.
According to the results, the freeze–dried and kneaded products exhibited higher dissolution rates than the drug alone, in
all the mediums. 相似文献
6.
Effect of Cyclodextrin Complexation of Curcumin on its Solubility and Antiangiogenic and Anti-inflammatory Activity in Rat Colitis Model 总被引:2,自引:0,他引:2
The purpose of the study was to prepare and evaluate the anti-inflammatory activity of cyclodextrin (CD) complex of curcumin
for the treatment of inflammatory bowel disease (IBD) in colitis-induced rat model. Inclusion complexes of curcumin were prepared
by common solvent and kneading methods. These complexes were further evaluated for increase in solubility of poorly soluble
curcumin. The inclusion complexes were characterized for enhancement in solubility, in vitro dissolution, surface morphology, infrared, differential scanning calorimetry, and X-ray studies. Solubility, phase solubility,
and in vitro dissolution studies showed that curcumin has higher affinity for hydroxypropyl-β-CD (HPβCD) than other CDs. HPβCD complex
of curcumin was further investigated for its antiangiogenic and anti-inflammatory activity using chick embryo and rat colitis
model. HPβCD complex of curcumin proved to be a potent angioinhibitory compound, as demonstrated by inhibition of angiogenesis
in chorioallantoic membrane assay. Curcumin- and HPβCD-treated rats showed a faster weight gain compared to dextran sulfate
solution (DSS) controls. Whole colon length appeared to be significantly longer in HPβCD-treated rats than pure curcumin and
DSS controls. An additional finding in the DSS-treated rats was the predominance of eosinophils in the chronic cell infiltrate.
Decreased mast cell numbers in the mucosa of the colon of CD of curcumin- and pure-curcumin-treated rats was observed. This
study concluded that the degree of colitis caused by administration of DSS was significantly attenuated by CD of curcumin.
Being a nontoxic natural dietary product, curcumin could be useful in the therapeutic strategy for IBD patients. 相似文献
7.
Esmeralda Morillo María Antonia Sánchez-Trujillo José Ramón Moyano Jaime Villaverde María Eulalia Gómez-Pantoja José Ignacio Pérez-Martínez 《PloS one》2012,7(9)
Solubilisation of six polycyclic aromatic hydrocarbons (PAHs) (acenaphthene, anthracene, fluoranthene, fluorene, phenanthrene and pyrene) by three synthetic cyclodextrins (CDs) (2-hydroxypropyl-β-CD, hydroxypropyl-γ-CD and ramdomly methylated-β-CD) was investigated in order to select the CD which presents the greatest increase in solubility and better complexation parameters for its use in contaminated scenarios. The presence of the three cyclodextrins greatly enhanced the apparent water solubility of all the PAHs through the formation of inclusion complexes of 1∶1 stoichiometry. Anthracene, fluoranthene, fluorene and phenanthrene clearly presented a higher solubility when β-CD derivatives were used, and especially the complexes with the ramdomly methylated-β-CD were favoured. On the contrary, pyrene presented its best solubility results when using 2-hydroxypropyl-γ-CD, but for acenaphthene the use of any of the three CDs gave the same results. Complementary to experimental phase-solubility studies, a more in-depth estimation of the inclusion process for the different complexes was carried out using molecular modelling in order to find a correlation between the degree of solubilisation and the fit of PAH molecules within the cavity of the different CDs and to know the predominant driving forces of the complexation. 相似文献
8.
The purpose of this study was to investigate the effect of cyclodextrins (CDs) on aqueous solubility, stability, and in vitro corneal permeability of delta-8-tetrahydrocannabinol (Δ8-THC). Phase solubility of Δ8-THC was studied in the presence of 2-hydroxypropyl-β-cyclodextrin (HPβCD), randomly methylated-β-cyclodextrin (RMβCD) and
sulfobutyl ether-β-cyclodextrin sodium salt (SβCD). Stability of Δ8-THC in 5% w/v aqueous CD solutions, as a function of pH, was studied following standard protocols. In vitro corneal permeation of Δ8-THC (with and without CDs) across excised rabbit cornea was also determined. Phase-solubility profile of Δ8-THC in the presence of both HPβCD and RMβCD was of the AP type, whereas, with SβCD an AL type was apparent. Aqueous solubility of Δ8-THC increased to 1.65, 2.4, and 0.64 mg/mL in the presence of 25% w/v HPβCD, RMβCD, and SβCD, respectively. Significant degradation of Δ8-THC was not observed within the study period at the pH values studied, except for at pH 1.2. Transcorneal permeation of Δ8-THC was dramatically improved in the presence of CDs. The results demonstrate that CDs significantly increase aqueous solubility,
stability, and transcorneal permeation of Δ8-THC. Thus, topical ophthalmic formulations containing Δ8-THC and modified beta CDs may show markedly improved ocular bioavailability. 相似文献
9.
The objectives of this research were to prepare and characterize inclusion complexes of clonazepam with β-cyclodextrin and
hydroxypropyl-β-cyclodextrin and to study the effect of complexation on the dissolution rate of clonazepam, a water-insoluble
lipid-lowering drug. The phase-solubility profiles with both cyclodextrins were classified as AP-type, indicating the formation of 2:1 stoichiometric inclusion complexes. Gibbs free energy ( DGtro ) \left( {\Delta {G_{tr}}^o} \right) values were all negative, indicating the spontaneous nature of clonazepam solubilization, and they decreased with increase
in the cyclodextrins concentration, demonstrating that the reaction conditions became more favorable as the concentration
of cyclodextrins increased. Complexes of clonazepam were prepared with cyclodextrins by various methods such as kneading,
coevaporation, and physical mixing. The complexes were characterized by Fourier transform infrared spectroscopy and differential
scanning calorimetry studies. These studies indicated that complex prepared kneading and coevaporation methods showed successful
inclusion of the clonazepam molecule into the cyclodextrins cavity. The complexation resulted in a marked improvement in the
solubility and wettability of clonazepam. Among all the samples, complex prepared with hydroxypropyl-β-cyclodextrin by kneading
method showed highest improvement in in vitro dissolution rate of clonazepam. Mean dissolution time of clonazepam decreased significantly after preparation of complexes
and physical mixture of clonazepam with cyclodextrins. Similarity factor indicated significant difference between the release
profiles of clonazepam from complexes and physical mixture and from plain clonazepam. Tablets containing complexes prepared
with cyclodextrins showed significant improvement in the release profile of clonazepam as compared to tablet containing clonazepam
without cyclodextrins. 相似文献
10.
The objective of this work is physicochemical characterization of nimesulide-cyclodextrin binary systems both in solution
and solid state and to improve the dissolution properties of nimesulide (N) via complexation with α-, β, and γ-cyclodextrins
(CDs). Detection of inclusion complexation was done in solution by means of phase solubility analysis, mass spectrometry,
and 1H nuclear magnetic resonance (1H-NMR) spectroscopic studies, and in solid state using differential scanning calorimetry (DSC), powder x-ray diffractometry
(X-RD), scanning electron microscopy (SEM), and in vitro dissolution studies. Phase solubility, mass spectrometry and 1H-NMR studies in solution revealed 1∶1 M complexation of N with all CDs. A true inclusion of N with β-CD at 1∶2 M in solid
state was confirmed by DSC, powder X-RD and SEM studies. Dissolution properties of N-CD binary systems were superior when
compared to pure N. 相似文献
11.
Marcílio S. S. Cunha-Filho Bruno Dacunha-Marinho Juan J. Torres-Labandeira Ramón Martínez-Pacheco Mariana Landin 《AAPS PharmSciTech》2007,8(3):E68-E77
The purpose of this research was to explore the utility of β cyclodextrin (βCD) and β cyclodextrin derivatives (hydroxypropyl-β-cyclodextrin
[HPβCD], sulfobutylether-β-CD [SB\CD], and a randomly methylated-β-CD [RMβCD]) to form inclusion complexes with the antitumoral
drug, β-lapachone (βLAP), in order to overcome the problem of its poor water solubility. RMβCD presented the highest efficiency
for βLAP solubilization and was selected to develop solid-state binary systems. Differential scanning calorimetry (DSC), X-ray
powder diffractometry (XRPD), Fourier transform infrared (FTIR) and optical and scanning electron microscopy results suggest
the formation of inclusion complexes by both freeze-drying and kneading techniques with a dramatic improvement in drug dissolution
efficiency at 20-minute dissolution efficiency (DE20-minute 67.15% and 88.22%, respectively) against the drug (DE20-minute 27.11%) or the βCD/drug physical mixture (DE20-minute 27.22%). However, the kneading method gives a highly crystalline material that together with the adequate drug dissolution
profile make it the best procedure in obtaining inclusion complexes of RMβCD/βLAP convenient for different applications of
βLAP.
Published: July 27, 2007 相似文献
12.
Farouk Semcheddine Nida El Islem Guissi XueYin Liu ZuoMin Wu Bo Wang 《AAPS PharmSciTech》2015,16(3):704-715
The aims of this study were to enhance the solubility and dissolution rate of nimodipine (ND) by preparing the inclusion complexes of ND with sulfobutylether-b-cyclodextrin (SBE-β-CD) and 2-hydroxypropyl-b-cyclodextrin (HP-β-CD) and to study the effect of the preparation method on the in vitro dissolution profile in different media (0.1 N HCl pH 1.2, phosphate buffer pH 7.4, and distilled water). Thus, the inclusion complexes were prepared by kneading, coprecipitation, and freeze-drying methods. Phase solubility studies were conducted to characterize the complexes in the liquid state. The inclusion complexes in the solid state were investigated with differential scanning calorimetry (DSC), X-ray diffractometry (X-RD), and Fourier transform infrared spectroscopy (FT-IR). Stable complexes of ND/SBE-β-CD and ND/HP-β-CD were formed in distilled water in a 1:1 stoichiometric inclusion complex as indicated by an AL-type diagram. The apparent stability constants (Ks) were 1334.4 and 464.1 M−1 for ND/SBE-β-CD and ND/HP-β-CD, respectively. The water-solubility of ND was significantly increased in an average of 22- and 8-fold for SBE-β-CD and HP-β-CD, respectively. DSC results showed the formation of true inclusion complexes between the drug and both SBE-β-CD and HP-β-CD prepared by the kneading method. In contrast, crystalline drug was detectable in all other products. The dissolution studies showed that all the products exhibited higher dissolution rate than those of the physical mixtures and ND alone, in all mediums. However, the kneading complexes displayed the maximum dissolution rate in comparison with drug and other complexes, confirming the influence of the preparation method on the physicochemical properties of the products. 相似文献
13.
Complexation of celecoxib with hydroxypropyl β-cyclodextrin (HPβCD) in the presence and absence of 3 hydrophilic polymers—polyvinyl
pyrrolidone (PVP), hydroxypropyl methylcellulose (HPMC), and polyethylene glycol (PEG)—was investigated with an objective
of evaluating the effect of hydrophilic polymers on the complexation and solubilizing efficiencies of HPβCD and on the dissolution
rate of celecoxib from the HPβCD complexes. The phase solubility studies indicated the formation of celecoxib-HPβCD inclusion
complexes at a 1∶1M ratio in solution in both the presence and the absence of hydrophilic polymers. The complexes formed were
quite stable. Addition of hydrophilic polymers markedly enhanced the complexation and solubilizing efficiencies of HPβCD.
Solid inclusion complexes of celecoxib-HPβCD were prepared in 1∶1 and 1∶2 ratios by the kneading method, with and without
the addition of hydrophilic polymers. The solubility and dissolution rate of celecoxib were significantly improved by complexation
with HPβCD. The celecoxib-HPβCD (1∶2) inclusion complex yielded a 36.57-fold increase in the dissolution rate of celecoxib.
The addition of hydrophilic polymers also markedly enhanced the dissolution rate of celecoxib from HPβCD complexes: a 72.60-,
61.25-, and 39.15-fold increase was observed with PVP, HPMC, and PEG, respectively. Differential scanning calorimetry and
X-ray diffractometry indicated stronger drug amorphization and entrapment in HPβCD because of the combined action of HPβCD
and the hydrophilic polymers.
Published: September 29, 2006 相似文献
14.
Mamdouh M. Ghorab Heba M. Abdel-Salam Marwa A. El-Sayad Mohammed M. Mekhel 《AAPS PharmSciTech》2004,5(4):63-68
The purpose of this research was to evaluate β-cyclodextrin (β-CD) as a vehicle, either singly or in blends with lactose (spray-dried
or monohydrate), for preparing a meloxicam tablet. Aqueous solubility of meloxicam in presence of β-CD was investigated. The
tablets were prepared by direct compression and wet granulation techniques. The powder blends and the granules were evaluated
for angle of repose, bulk density, compressibility index, total porosity, and drug content. The tablets were subjected to
thickness, diameter, weight variation test, drug content, hardness, friability, disintegration time, and in vitro dissolution
studies. The effect of β-CD on the bioavailability of meloxicam was also investigated in human volunteers using a balanced
2-way crossover study. Phase-solubility studies indicated an AL-type diagram with inclusion complex of 1∶1 molar ratio. The powder blends and granules of all formulations showed satisfactory
flow properties, compressibility, and drug content. All tablet formations prepared by direct compression or wet granulation
showed acceptable mechanical properties. The dissolution rate of meloxicam was significantly enhanced by inclusion of β-CD
in the formulations up to 30%. The mean pharmacokinetic parameters (Cmax, Ke, and area under the curve [AUC]0−∞) were significantly increased in presence of β-CD. These results suggest that β-CD would facilitate the preparation of meloxicam
tablets with acceptable mechanical properties using the direct compression technique as there is no important difference between
tablets prepared by direct compression and those prepared by wet granulation. Also, β-CD is particularly useful for improving
the oral bioavailablity of meloxicam. 相似文献
15.
Ana Figueiras Jorge M. G. Sarraguça Alberto A. C. C. Pais Rui A. Carvalho J. Francisco Veiga 《AAPS PharmSciTech》2010,11(1):233-240
In this study, we investigate how the effect of l-arginine (ARG) and cyclodextrins upon omeprazole (OME) stability and solubility. The effect of the presence of ARG on the
apparent stability constants (K1:1) of the inclusion complexes formed between OME and each cyclodextrin, β-cyclodextrin (βCD), and methyl-β-cyclodextrin (MβCD)
is studied by phase solubility diagrams and nuclear magnetic resonance (NMR) spectroscopy. The interaction of OME with those
cyclodextrins, in the presence of ARG, is characterized using NMR spectroscopy and molecular dynamics simulations. ARG significantly
increases the drug solubility and complex stability, in comparison to inclusion complexes formed in its absence. The effect
is more pronounced for the OME:βCD complex. ARG also contributes to a larger stability of OME when free in aqueous solution.
The combination of ARG with cyclodextrins can represent an important tool to develop stable drug formulations. 相似文献
16.
The aim of this study was to improve the solubility and oral bioavailability of clozapine (CLZ), a poorly water-soluble drug subjected to substantial first-pass metabolism, employing cyclodextrin complexation technique. The inclusion complexes were prepared by an evaporation method. Phase solubility studies, differential scanning calorimetry, X-ray powder diffraction, and Fourier transform infrared spectroscopy were used to evaluate the complexation of CLZ with hydroxypropyl-β-cyclodextrin (HP-β-CD) and the formation of true inclusion complexes. Characterization and dissolution studies were carried out to evaluate the orally disintegrating tablets (ODTs) containing CLZ/HP-β-CD complexes prepared by direct compression. Finally, the bioavailability studies of the prepared ODTs were performed by oral administration to rabbits. The ODTs showed a higher in vitro dissolution rate and bioavailability compared with the commercial tablets. It is evident from the results herein that the developed ODTs provide a promising drug delivery system in drug development, owing to their excellent performance of a rapid onset of action, improved bioavailability, and good patient compliance. 相似文献
17.
Peixiao Tang Lei Wang Xiaoli Ma Kailin Xu Xinnuo Xiong Xiaoxiang Liao Hui Li 《AAPS PharmSciTech》2017,18(1):104-114
Posaconazole is a triazole antifungal drug that with extremely poor aqueous solubility. Up to now, this drug can be administered via intravenous injection and oral suspension. However, its oral bioavailability is greatly limited by the dissolution rate of the drug. This study aimed to improve water solubility and dissolution of posaconazole through characterizing the inclusion complexes of posaconazole with β-cyclodextrin (β-CD) and 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD). Phase solubility studies were performed to calculate the stability constants in solution. The results of FT-IR, PXRD, 1H and ROESY 2D NMR, and DSC all verified the formation of the complexes in solid state. The complexes showed remarkably improved water solubility and dissolution rate than pure posaconazole. Especially, the aqueous solubility of the DM-β-CD complex is nine times higher than that of the β-CD complex. Preliminary in vitro antifungal susceptibility tests showed that the two inclusion complexes maintained high antifungal activities. These results indicated that the DM-β-CD complexes have great potential for application in the delivery of poorly water-soluble antifungal agents, such as posaconazole. 相似文献
18.
Maria Florencia Mazzobre Cristina Isabel dos Santos Maria del Pilar Buera 《Food biophysics》2011,6(2):274-280
In the present work, inclusion complexes of α-terpineol (Terp) and β-cyclodextrin (BCD) were prepared by the coprecipitation
method. Phase solubility studies were performed and thermodynamic parameters involved in the complex formation were calculated.
The solubility of Terp increased linearly as the concentration of BCD was increased, confirming the 1:1 stoichiometry of the
complex. The stability constants decreased along with increasing temperature. The negative value of the enthalpy and of the
Gibbs free energy demonstrated that the process is exothermic and spontaneous. Since complexation gives more ordered systems,
the negative value obtained for the entropy change evidenced the encapsulation of Terp. Terp was completely encapsulated in
BCD at the preparation conditions and studied molar ratios, as confirmed in the freeze-dried samples by differential scanning
calorimeter. The presence of Terp greatly modified the BCD water sorption curves, and the amount of adsorbed water was lower
for the complexes. The limited water solubility of Terp could be overcome by the formation of BCD inclusion complexes, and
the complexes were stable at different storage conditions (relative humidities 11–97% and 25 °C). The obtained phase solubility
data are useful for food or pharmaceutical products formulation involving cyclodextrins and stability predictions. 相似文献
19.
《Bioscience, biotechnology, and biochemistry》2013,77(12):2340-2345
The complexation between two isomers of citral in lemongrass oil and varying types of cyclodextrins (CDs), α-CD, β-CD, and HP-β-CD, were studied by molecular modeling and physicochemical characterization. The results obtained revealed that the most favorable complex formation governing between citrals in lemongrass oil and CDs were found at a 1:2 mole ratio for all CDs. Complex formation between E-citral and CD was more favorable than between Z-citral and CD. The thermal stability of the inclusion complex was observed compared to the citral in the lemongrass oil. The release time course of citral from the inclusion complex was the diffusion control, and it correlated well with Avrami’s equation. The release rate constants of the E- and Z-citral inclusion complexes at 50 °C, 50% RH were observed at 1.32×10?2 h?1 and 1.43×10?2 h?1 respectively. 相似文献
20.
The aim of the present work was to improve the solubility and dissolution profile of Irbesartan (IRB), a poorly water-soluble
drug by formation of inclusion complex with β-cyclodextrin (βCD). Phase solubility studies revealed increase in solubility
of the drug upon cyclodextrin addition, showing AL—type of graph with slope less than one indicating formation of 1:1 stoichiometry inclusion complex. The stability constant
(K
s) was found to be 104.39 M−1. IRB–βCD binary systems were prepared by cogrinding, kneading using alcohol, kneading using aqueous alcohol, and coevaporation
methods. Characterization of the binary systems were carried out by differential scanning calorimetry, Fourier transform infrared
spectroscopy, scanning electron microscopy, X-ray diffraction, and proton nuclear magnetic resonance. The dissolution profiles
of inclusion complexes were determined and compared with those of IRB alone and physical mixture. Among the various methods,
coevaporation was the best in which the solubility was increased and dissolution rate of the drug was the highest. The study
indicated the usefulness of cyclodextrin technology to overcome the solubility problem of IRB. 相似文献