The equilibrium constant of β-cyclodextrin–phenolphtalein complex; influence of temperature and tetrahydrofuran addition

Zarzycki, Paweł K.; Lamparczyk, H.

doi:10.1016/s0731-7085(98)00150-2

Cited by 75 publications

(41 citation statements)

References 20 publications

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“…In most cases, increasing the temperature decreases the magnitude of the apparent stability constant of the drug/CD complex, possibly due to subsequent reduction in drug/CD interaction forces such as van der Waals and hydrophobic forces 17,18) . In this study, we believed that few SVA/CD complexes occurred at 65 .…”

Section: Discussionmentioning

confidence: 99%

Controlled Release of Simvastatin Acid Using Cyclodextrin Inclusion System

et al. 2007

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Simvastatin acid (SVA) has been reported to stimulate bone formation by increasing expression of BMP-2 in osteoblasts. Due to their multi-functional characteristics and bioadaptability, cyclodextrins (CDs) are capable of forming inclusion complexes with many drugs by including a whole drug molecule inside their cavity. In the present study, we prepared SVA/CD inclusion complex solutions with different pH values. These were then used to determine their SVA release behavior after coating on titanium substrates, as well as to clarify the characteristics of SVA/CD complexes per se. Results showed that the lower the pH value of the solution, the lower the release kinetics of SVA. Besides, the amount of crystalline complexes in the coatings increased with decrease in pH. These results suggested that the release rate of SVA depended on two factors: pH of the solution and concomitant crystallinity of the coating.

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Section: Discussionmentioning

confidence: 99%

Controlled Release of Simvastatin Acid Using Cyclodextrin Inclusion System

et al. 2007

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“…The changes in the solubility of fluconazole resulting from the presence of CDs at various concentrations were used to plot phase-solubility diagrams and to evaluate the stoichiometry and stability constant of the resultant complex. The apparent stability constant (K) was estimated from the phase-solubility diagrams according to the following equation [30] :…”

Section: Evaluation Of Fluonazole Solubility In the Presence Of Cdsmentioning

confidence: 99%

Sulfoalkyl ether β-cyclodextrin derivatives synthesized by a single step method as pharmaceutical biomaterials

et al. 2009

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We report a simple "one pot" single step method to synthesize sulfoalkyl ether -cyclodextrin (-CD) derivatives in aqueous solution, which avoids the limitations associated with commonly used organic synthesis of such derivatives including multi-step reactions, use of expensive, toxic, and often environmentally hazardous organic solvents and/or reagents. Using this method, we obtained sulfopropyl and sulfobutyl ethyl -CDs. We characterized these two derivatives and evaluated their ability to enhance solubility of fluconazole, a commonly used antifungal drug with poor water solubility. Experimental results indicate that these derivatives are structurally analogous to some of the commercially available -CD derivatives. More importantly, when they formed supramolecular inclusion complexes with fluconazole, they demonstrated similar, if not better, capacity to enhance fluconazole solubility compared with commercially available -CD derivatives, suggesting that the simple "one pot" single step synthesis may provide an effective alternative approach to produce large quantity of -CD derivatives as pharmaceutical biomaterials for medicinal applications.-cyclodextrin derivatives, "one pot" synthesis, aqueous solution, solubility enhancer, fluconazole, supramolecular inclusion complex Enzymatic degradation of one of the most widely used biomaterials, starch, results in cyclic oligosaccharides that are formed with D-glucopyranose units and generally known as cyclodextrins (CDs). Depending on the number of D-glucopyranose units that form the molecule, there are -CD, -CD, -CD, and so on (with 6, 7, 8 or more D-glucopyranose units, respectively). Among them -CD is the most widely used for reasons such as wide availability and preferred cavity dimensions, providing more than 95% of today's total supply [1,2] .One of the striking features of CDs is their molecular structure that has a hydrophilic outer surface and a somewhat lipophilic central cavity, and geometrically resembles a truncated conical shape (torus) [1,[3][4][5][6][7][8][9] . This unique structure allows many poorly soluble lipophilic complexes such as drug molecules to bind to them and form water soluble inclusion complexes. Thus, CDs have recently been recognized as useful supramolecular pharmaceutical biomaterials, and -CD is especially so due to its relatively low price [1,[3][4][5][6][7][8][9][10][11][12][13] . However, natural -CD itself, like other CDs, is poorly soluble in water at room temperature, which is a severe limitation for its wide use in pharmaceutics [4,7,9,10] . Therefore, in order to achieve better water solubility and greater bioavailability, functional groups such as alkyl-, hydroxyalkyl-, carboxyalkyl-, amino-, glucosyl-, sulfoalkyl-, were added to the dextrin molecules chemically or enzymatically, which results in various -CD derivatives [1,5,9,[11][12][13][14][15][16][17][18][19][20][21] . Among these derivatives, sulfoalkyl ether -CDs are highly water soluble and low toxic due to the anionic nature of the substituents, and thu...

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“…Bar systematically investigated steroid biotransformation by Rhodococcus erythropolis in the presence of natural and chemically modified CDs, they found that the biotransformation was strongly affected by the mode of the addition of the natural CDs [14][15][16]. Zarzycki demonstrated the influence of the temperature on the association constant of host-guest complexes formed by CDs [17][18][19], which help to select appropriate experimental condition. Furthermore, mathematical model was also proposed to study the influence of ␤-CD on the kinetics of steroid biotransformation, in the model framework the formation of complexes leads to an increase of the maximal reaction rate and a decrease of substrate inhibition [10,20,21].…”

Section: Introductionmentioning

confidence: 99%