Two types of inclusion realized in the complexation between phenobarbital and 2-hydroxypropyl-ß-cyclodextrin in aqueous solution

Multimodal Inclusion Complexes Between Barbiturates and 2‐Hydroxypropyl‐β‐Cyclodextrin in Aqueous Solution: Isothermal Titration Microcalorimetry, 13C NMR Spectrometry, and Molecular Dynamics Simulation

“…3 can be expressed in the form where [G t ] represents the total concentration of barbiturates, [CD f ] is the free concentration of HPCD, and K i and Δ H i are the association constant and the enthalpy change for the i th type of inclusion complex (G:CD) i , respectively. The values of these parameters can be computed from the actual calorimetric data with an iterative nonlinear least‐square method using the FACOM M 380R computer program 18,19,36. The initial value of Δ H was experimentally estimated from the slope of the initial part of the titration curve.…”

“…Isothermal titration microcalorimetry is an ideal analytical method for this purpose. The values of K , n , and Δ H were directly calculated from the data using programs both on the basis of a multiple‐stepwise model and also multiple types of inclusion complexes at a molar ratio of 1:1 in a single experiment at a suitable temperature 9,17–20. This method also allowed simultaneous determination of the thermodynamic parameters (Δ G and Δ S ) using the well‐known thermodyamic formula: Δ G = Δ− RT ln K = ΔH − T Δ S where R is gas constant and T is temperature.…”

“…For complexation between phenobarbital (PHB) and 2‐hydroxypropyl‐β‐CD (HPCD) in aqueous solution, two different inclusion types with a 1:1 stoichiometry were detected by microcalorimetry, 13 C NMR spectroscopy, and molecular dynamics simulations 18. A single type of complex with a 1:1 stoichiometry in the solid state was distinguishable using fast atom bambardnent (FAB) mass spectrometry 19.…”

Sertaconazole/hydroxypropyl-β-cyclodextrin complexation: Isothermal titration calorimetry and solubility approaches

“…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.…”

The Determination of Non-covalent Complexes of Diclofenac Sodium and Cyclodextrins by Electrospray Ionization/Time-of-Flight Mass Spectrometry

“…The resulting CD inclusion complexes with drugs are widespread application in the pharmaceutical industry as the complexes can improve solubility, stability, and bioavailability of the guest molecules. [13][14][15][16][17][18][19][20] However these applications are probably limited when the guest is less soluble or insoluble in water, such as sodium {2-[(2,6-dichlorophenyl) amino] phenyl} acetate (diclofenac sodium, DS) which we discussed in this article. When a guest molecule is bulky or long relative to the dimensions of CD cavity, two CD molecules are frequently bound to a single guest molecule to form a 2:1 CD-guest non-covalent complex.…”