Multimodal inclusion complexes of ampicillin with β-cyclodextrins in aqueous solution

Aki, Hatsumi; Niiya, Tokihiro; Iwase, Yukiko; Kawasaki, Yuhsuke; Kumai, Kaori; Kimura, Takayoshi

doi:10.1016/j.tca.2003.01.004

Cited by 30 publications

(10 citation statements)

References 11 publications

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“…However, the proposed complexes were not stable along the simulation time of 2.5 ns, reverting to structure A2 or to complexes in which the AMP molecule interacted with hydroxyl groups outside the b-CD cavity (structures not shown). This result is also in accordance with previous MD simulations, 41 in which the AMP guest gradually slipped out of the CD cavity after 20 ps when the interactions occurred through its polar moiety.…”

Section: Theoretical Calculations Of B-cd:amp Complexessupporting

confidence: 93%

Superstructure based on β-CD self-assembly induced by a small guest molecule

Sousa

Lima

Denadai

et al. 2012

Phys. Chem. Chem. Phys.

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The size, shape and surface chemistry of nanoparticles play an important role in cellular interaction. Thus, the main objective of the present study was the determination of the β-cyclodextrin (β-CD) self-assembly thermodynamic parameters and its structure, aiming to use these assemblies as a possible controlled drug release system. Light scattering measurements led us to obtain the β-CD’s critical aggregation concentration (cac) values, and consequently the thermodynamic parameters of the β-CD spontaneous self-assembly in aqueous solution: ΔaggGo = − 16.31 kJ mol−1, ΔaggHo = − 26.48 kJ mol−1 and TΔaggSo = − 10.53 kJ mol−1 at 298.15 K. Size distribution of the self-assembled nanoparticles below and above cac was 1.5 nm and 60–120 nm, respectively. The number of β-CD molecules per cluster and the second virial coefficient were identified through Debye’s plot and molecular dynamic simulations proposed the three-fold assembly for this system below cac. Ampicillin (AMP) was used as a drug model in order to investigate the key role of the guest molecule in the self-assembly process and the β-CD:AMP supramolecular system was studied in solution, aiming to determine the structure of the supramolecular aggregate. Results obtained in solution indicated that the β-CD’s cac was not affected by adding AMP. Moreover, different complex stoichiometries were identified by nuclear magnetic resonance and isothermal titration calorimetry experiments.

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Section: Theoretical Calculations Of B-cd:amp Complexessupporting

confidence: 93%

Superstructure based on β-CD self-assembly induced by a small guest molecule

Sousa

Lima

Denadai

et al. 2012

Phys. Chem. Chem. Phys.

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“…The cavity size is suitable for common pharmaceutical drugs with molecular weights between 200 and 800 g mol −1 (3,14). Many drugs have been complexed with βCD, leading to a significantly increase in solubility of these molecules (2,4,(15)(16)(17)(18).…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Properties and Dissolution Studies of Dexamethasone Acetate-β-Cyclodextrin Inclusion Complexes Produced by Different Methods

et al. 2008

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Inclusion complexes between dexamethasone acetate (DMA), a poorly water soluble drug, and beta-cyclodextrin (betaCD) 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 betaCD (33-fold) and was classified as A(L)-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.

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“…If i is equal to or greater than 2, it is assumed that several types of inclusion complex are independently formed. 18 The analysis of the calorimetry data allows the determination of the affinity constant (K i ), the stoichiometry number (n i ) and the complexation enthalpy (DH ITC i ) for each type of complex, using the equation:…”

Section: Isothermal Titration Microcalorimetry (Itc)mentioning

confidence: 99%

“…Previous articles have reported the formation of several types of 1:1 complexes for systems comprising barbiturates or ampicillin and HP-b-CD, due to the inclusion of the drug through different hydrophobic groups into the CD cavity. 10,18,23,24 SN structure contains three rings with potential affinity for the HP-b-CD cavity. At pH 1.2, imidazolyl group is protonized; the chlorobenzothiophene and the 2,4-dichlorophenyl groups being the most likely to enter into the CD cavity (Fig.…”

Section: Complexes Of Sn:hp-b-cd In Solutionmentioning

confidence: 99%