scholarly journals Soluble 1:1 complexes and insoluble 3:2 complexes – Understanding the phase-solubility diagram of hydrocortisone and γ-cyclodextrin

2017 ◽  
Vol 531 (2) ◽  
pp. 504-511 ◽  
Author(s):  
Christian Schönbeck ◽  
Tobias L. Madsen ◽  
Günther H. Peters ◽  
René Holm ◽  
Thorsteinn Loftsson
2009 ◽  
Vol 22 (3) ◽  
pp. 232-241 ◽  
Author(s):  
Freimar Segura-Sanchez ◽  
Kawthar Bouchemal ◽  
Geneviève Lebas ◽  
Christine Vauthier ◽  
Néréide S. Santos-Magalhaes ◽  
...  

2012 ◽  
Vol 8 ◽  
pp. 1644-1651 ◽  
Author(s):  
Hai Ming Wang ◽  
Gerhard Wenz

Various hydrophilic γ-cyclodextrin (CD) thioethers, containing neutral or ionic side arms were found to form molecular disperse solutions of C60 in water reaching concentrations of 15 mg/L. Equilibrium state was approached after seven days without the use of organic cosolvents. The 1:2 stoichiometry of the C60/γ-CD thioether complexes was demonstrated by a parabolic phase-solubility diagram. In contrast, native γ-CD forms nanoparticles with C60. Particle sizes of C60 were determined by dynamic light scattering.


2012 ◽  
Vol 506 ◽  
pp. 433-436 ◽  
Author(s):  
W. Samprasit ◽  
Theerasak Rojanarata ◽  
Prasert Akkaramongkolporn ◽  
Tanasait Ngawhirunpat ◽  
Praneet Opanasopit

Cyclodextrin complexation and pH adjustments have been reported as useful tools to increase the solubility of drug. The aim of this study was to investigate the influence of both cyclodextrin and pH on the overall solubility of ketoprofen. β-cyclodextrin (β-CD) and hydroxypropyl β-cyclodextrin (HP-β-CD) were used for the preparation of inclusion complex by shaking method in aqueous solution at pH 2, 5, 7 and 10. It was found that the solubility of ketoprofen significantly increased with increasing pH and cyclodextrin concentration, showing AL type phase solubility diagram. However, the apparent stability constant of complex (KC) was found to decrease with increasing pH due to the decreased affinity of ionized drug to cyclodextrin cavity. The ionization of ketoprofen increased when the pH was raised, corresponding with its higher zeta potential. The result indicated that the solubility of ketoprofen could be improved by using a combined approach of pH adjustments and complexation with cyclodextrin. Moreover, the unionized drug that was formed by pH adjustments interacted with cyclodextrin more strongly than the ionized drug.


2020 ◽  
Vol 13 (2) ◽  
pp. 132-144
Author(s):  
Prajapati Jagruti B. ◽  
Sawant Krutika K. ◽  
Bhramanand Dubey

Background: Many CNS drugs have low bioavailability due to their poor water solubility of extensive first-pass metabolism and hence have less effectiveness. Objective: The present study aims to enhance the solubility and oral bioavailability of poorly watersoluble antipsychotic drug Amisulpride (AMS) through complexation with 2-hydroxypropyl β- cyclodextrin (HPβCD). It has slow and erratic absorption after oral administration. Methods: This report describes the study of the phase solubility diagram, preparation of the inclusion complex and tablet of prepared inclusion complex, characterization of the physico-chemical properties of the inclusion complex and tablet. Results: In-vitro study (100 % drug release in 15 minutes), and in-vivo study of an AL-type (linear type) phase solubility diagram indicated a complex of AMS-HP-β-CD with the constant complex formation of 13245 M−1 at 37°C. The complex formation was confirmed by DSC, IR, and X-ray diffraction. The extent of absorption of the complex was determined in rats and was compared with that of pure drug and the market product. The peak plasma concentration of pure drug was 30.05 ± 1.3 ng/ml (Cmax) at 60 ± 3 min, whereas with the market product the value was 54.85 ± 1.2 ng/ml at 40 ± 1 min and with AMS-HPβCD inclusion complex the value was 79.01 ± 1.5 ng/ml. The AUCtot of the pure drug was 2980.34±3.6, the market product was 7238.73±2.9 and of the inclusion complex was 11871.1±2.8. Conclusion: Pharmacodynamic studies in mice showed improved effectiveness of drug compared to pure drug. The oral bioavailability of AMS was improved from 48% to 78%.


2013 ◽  
Vol 11 (2) ◽  
pp. 107-116 ◽  
Author(s):  
Shivanand Hiremath ◽  
Ganesh Godge

Nelfinavir is a poorly water-soluble antiretroviral drug with relatively low bioavailability. In the present study, the practically insoluble drug, nelfinavir (NFV) and its inclusion complexes with hydroxypropyl-?-cyclodextrin (HP-?-CD) were investigated to improve the aqueous solubility and the dissolution rate of the drug, thus enhancing its bioavailability. The phase solubility diagram with HP-?-CD was classified as AL-type at all temperatures investigated, indicating the formation of higher order complexes. The apparent complexation constants (K1:1) calculated from phase solubility diagram were 145.49, 188.45 and 255.54 M-1 at 25, 37 and 45 ± 0.5°C, respectively. Aqueous solubility and dissolution studies indicated that the dissolution rates were remarkably increased; this could be mainly attributed to the improved solubility and dissolution associated with inclusion complex between drug and HP- ? -CD. Absence of endothermic and characteristic diffraction peaks corresponding to NFV was observed for the inclusion complex in DSC and PXRD. FT-IR study indicated that the presence of intermolecular hydrogen bonds between NFV and HP-?-CD in inclusion complex, resulting in the formation of amorphous form. DOI: http://dx.doi.org/10.3329/dujps.v11i2.14558 Dhaka Univ. J. Pharm. Sci. 11(2): 107-116, 2012 (December)


2005 ◽  
Vol 73 (3) ◽  
pp. 147-161 ◽  
Author(s):  
Charumanee S. ◽  
Weiss-Greiler P. ◽  
Wolschann P. ◽  
Viernstein H. ◽  
Titwan A. ◽  
...  

Thermodynamic studies of piroxicam in aqueous solution complexed with β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD) and two β-cyclodextrin derivatives, hydroxypropyl-β-cyclodextrin (HP-P-CD) and methyl-β-cyclodextrin (Me-β-CD) were performed at different temperatures and pH values using the phase solubility method. The phase solubility diagrams of β-CD, γ-CD and HP-β-CD is of AL-type behavior, indicating the formation of 1:l complexes. The related stability constants range from β-CD > γ-CD > Me-β-CD > HP-β-CD, respectively. An Ap-type solubility diagram is observed for Me-β-CD, indicating the formation of 1:2 complexes at higher CD concentrations. From the temperature dependence of the equilibrium constants the reaction enthalpies and entropies have been determined. The contributions of the reaction entropies are small and no enthalpy-entropy-compensation is observed, except for γ-CD, where a very small negative reaction entropy could be estimated. Moreover, the influence of the pH value is rather high because the differently charged forms of piroxicam show different solubility behavior in water.


2020 ◽  
Vol 103 (3) ◽  
pp. 743-746
Author(s):  
Ana Carolina Kogawa ◽  
Leena Peltonen ◽  
Hérida Regina Nunes Salgado ◽  
Marlus Chorilli

Abstract Background Rifaximin is an oral antimicrobial with a daily dose ranging from 600 to 800 mg. It is classified as Class IV in the Biopharmaceutic Classification System. Thus, rifaximin-based samples were developed by complexation to β-cyclodextrin using a phase solubility diagram, and malaxation and decreasing particle size using wet milling. Objective Concomitant to the pharmaceutical technology, a stability studywas undertaken with the objective of verifying the integrity of the drug. Methods The stability of the new samples were studied for 6 months, without interruption, under controlled conditions of temperature and humidity in a climatic chamber. They were analyzed simultaneously by HPLC and microbiological turbidimetry at zero, 3, and 6 months. Results Two of the samples follow second reaction order and one follows zero reaction order. Microbiological analysis proved to be important in assessing the potency of rifaximin in one of the samples, and its results were more consistent than the results by HPLC. Conclusions The rifaximin-based samples were stable under controlled temperature and humidity conditions and the physical-chemical and microbiological methods were able to evaluate their behavior during the 6-month study. Highlights It is worth considering the development of these products, since the design process of formulation and pharmaceutical technology is financially more attractive than the development of new drugs that require high levels of investment in research and development, innovation of public policies, and regulatory actions.


2015 ◽  
Vol 11 ◽  
pp. 2763-2773 ◽  
Author(s):  
Waratchada Sangpheak ◽  
Jintawee Kicuntod ◽  
Roswitha Schuster ◽  
Thanyada Rungrotmongkol ◽  
Peter Wolschann ◽  
...  

The aim of this work is to improve physical properties and biological activities of the two flavanones hesperetin and naringenin by complexation with β-cyclodextrin (β-CD) and its methylated derivatives (2,6-di-O-methyl-β-cyclodextrin, DM-β-CD and randomly methylated-β-CD, RAMEB). The free energies of inclusion complexes between hesperetin with cyclodextrins (β-CD and DM-β-CD) were theoretically investigated by molecular dynamics simulation. The free energy values obtained suggested a more stable inclusion complex with DM-β-CD. The vdW force is the main guest–host interaction when hesperetin binds with CDs. The phase solubility diagram showed the formation of a soluble complex of AL type, with higher increase in solubility and stability when hesperetin and naringenin were complexed with RAMEB. Solid complexes were prepared by freeze-drying, and the data from differential scanning calorimetry (DSC) confirmed the formation of inclusion complexes. The data obtained by the dissolution method showed that complexation with RAMEB resulted in a better release of both flavanones to aqueous solution. The flavanones-β-CD/DM-β-CD complexes demonstrated a similar or a slight increase in anti-inflammatory activity and cytotoxicity towards three different cancer cell lines. The overall results suggested that solubilities and bioactivities of both flavanones were increased by complexation with methylated β-CDs.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Runmiao Wang ◽  
Hui Zhou ◽  
Shirley W. I. Siu ◽  
Yong Gan ◽  
Yitao Wang ◽  
...  

Cyclodextrins are widely used for the solubilisation of poorly soluble drugs in the formulations. However, current cyclodextrin formulation development strongly depends on trial-and-error in the laboratory, which is time-consuming and high cost. The aim of this research was to compare three modeling approaches (Docking, molecular dynamics (MD), and quantum mechanics (QM)) for cyclodextrin/drug complexation. Ibuprofen was used as a model drug. Binding free energy from three simulation methods was calculated as an important parameter to compare with the experimental results. Docking results from AutoDock Vina program showed that the scoring of complexation capability between ibuprofen and cyclodextrins is alpha (α), gamma (γ), beta (β), and HP-beta-cyclodextrins, which indicated similar ranking with the results from phase, solubility diagram experiments. MD simulation indicated that ibuprofen could form the stable complexes withβ-,γ-, and HP-β-cyclodextrins, but not for alpha cyclodextrin. Binding free energies from the MD simulation forβ-,γ-, and HP-β-cyclodextrins were −3.67, −0.67, and −3.87 kcal/mol, individually. The enthalpies of QM simulation forβ-,γ-, and HP-β-cyclodextrins were −17.22, −14.75, and −20.28 kcal/mol, respectively. Results from all three modeling approaches showed similar ranking between ibuprofen and four cyclodextrin molecules as the experimental data. However, MD simulation with entropy calculation had the closest value to experimental data forβand HP-beta-cyclodextrins. Thus, MD simulation with MM-PBSA method may be fit toin silicoscreen for cyclodextrin formulations.


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