B-cyclodextrin

In this study, complexation of A9-THC and cannabidiol (prepared by freeze drying) with randomly methylated b-cyclodextrin and hydroxypropyl-b-cyclodextrin (HP-fi-CD) was studied by the phase-solubiHty method. The aqueous solubility of CBD and THC increased as a function of CD concentration, and the dissolution increased for THC and CBD cyclodextrin complexes significantly in contrast to plain THC and CBD. These results demonstrate that cyclodextrins increased both the aqueous solubility and dissolution rate... 

Lubda, D., Cabrera, K., Nakanishi, K., Lindner, W. (2003). Monolithic silica columns with chemically bonded b-cyclodextrin as a stationary phase for enantiomer separations of chiral pharmaceuticals. Anal. Bioanal. Chem. 377, 892-901. 

Cavalli R. et ah. Solid lipid nanoparticles as carriers of hydrocortisone and progesterone complexes with b-cyclodextrins, Int. J. Pharm., 182, 59, 1999. 

Luna EA, et al. Fractionation and characterization of 4-sulfobutylether derivatives of cyclomaltoheptaose (b-cyclodextrin). Carbohydr Res 1997 299 103. 

Palmieri, G. F., Galli-Angeli, D., Giovannucci, G, and Martelli, S. 1997. Inclusion of methoxybutropate in P- and hydroxypropy B-cyclodextrins comparison of preparation methdUlsig Develop. Ind. Pharm. 

B cyclodextrin glycosyl-transferase Ca2+ formation (and hydrolysis) of 1,4-a-D-glucoside bonds... 

Canceill, J. Jullien, L. Lacombe, L. Lehn, J.-M., (1992) 62. Channel-type molecular structures. Synthesis of bouquet-shaped molecules based on a B-cyclodextrin core Helv. Chim. Acta 75, 791. 

Tabushi, I. Kuroda, Y., Yamada, M., (1988) Dynamic molecular motions of guest molecules in modified b-cyclodextrins Tetrahedron Lett. 29, 1413-1426. 

M. Jung and V. Schurig, Extending the scope of enantiomer separation by capillary supercritical fluid chromatography on immobilized polysiloxane anchored permethyl-B-cyclodextrin (Chirasil-Dex), J. High Resolut. Chromstogr., 76 215 (1993). 

Drugs possessing a steroid structure are particularly easy to separate by CEC (see also the section on Steroids). Euerby et al. [203] published the separation of tipredane and five related compounds. A conventional capillary packed with 3 mm Spherisorb ODS-1 can be used for this purpose using acetonitrile-Tris pH 7.8 buffer (8 2) (50 mmol/1). Under these conditions it is also possible to separate the C-17 diastereoi-somer of the active compound without the addition of a chiral modifier (b-cyclodextrin is needed to achieve a comparable result in other separation modes) (Fig. 10.25). The elution order of individual compounds was exactly the same as with reversed phase chromatography, and it was concluded that with unionized species HPLC methods should be directly transferable to the CEC mode. 

However, the largest number of studies performed where chirality is induced upon dissolution of two solutes in a solvent system concerns the particular instance where the chiral solute is one of the cyclodextrins. These compounds are torus shaped, cyclic oligosaccharides consisting of six (denoted as a-cyclodextrin), seven (B-cyclodextrin), or eight (y-cyclodextrin) glucose units. Owing to their hydrophobic... 

From a study of the complexation between benzoylbenzoic acids and B-cyclodextrin [30], it was shown that the phenyl portion of the compounds was included within the cyclodextrin cavity, and that the induced CD originated from the carboxyl group. Insight into the nature of the interaction was obtained through the pH dependence of the magnitude of the induced CD, where it was noted that full ionization of the carboxyl group totally eliminated the induced CD through dissociation of the complex. 

Vibrational fine structure within the induced CD bands of several monosubstituted benzenes has been discerned when these were included in B-cyclodextrin [31]. From prior knowledge of the vibrational energies, it was possible to identify the modes which coupled into the CD bands. 

The predictions reached on the basis of the induced CD data were verified through calculations conducted using the Kirkwood-Tinoco equations. In a related work, CD induced through complexation with B-cyclodextrin in a series of ortho, meta, and para-substituted benzenes was compared [33]. The magnitude of the induced CD effects revealed that strong complexation took place only for para substitution, and that the presence of substituents at the ortho or meta positions interfered with the inclusion process. 

A novel mode of complexation across the "lid" of the cyclodextrin cavity was proposed for the interaction of p-dimethylarainobenzoic acid with 2,6-dimethyl-B-cyclodextrin [34]. Although the induced CD was weaker than that normally encountered for axial inclusion in the cyclodextrin cavity, it... 

Figure 5. CD within the near-UV region of azanaphthalenes after formation of inclusion complexes with B-cyclodextrin. Spectra are shown for (a) quinoline, (b) phthalazine, (c) isoquinoline, and (d) cinnoline (data adapted from reference [38]).

A variety of studies have been conducted in which the CD induced in pharmaceutically active compounds was used to characterize the nature of the inclusion complexes. The interaction of four barbiturates with B-cyclodextrin was studied by solubility and chiroptical methods [55]. It was found that the solubility of the barbiturates increased significantly upon formation of the inclusion complexes, and this enhancement was used to deduce the formation constants for the associated species. The induced CD data were also used to evaluate the strength of the complexes, with the relative strength of interaction with 6-cyclodextrin being phenobarbital > pentobarbital > amobarbital > barbital. 

It was found that B-cyclodextrin will form 1 1 complexes with the entire series of anti-inflammatory fanamates, with the exception of the parent compound anthranilic acid [56], Inclusion complexes could not be formed with a-cyclodextrin, indicating that the cavity of this host was too small to permit complexation. Formation of the inclusion complexes... 

Figure 10. CD spectra of (a) retinoic acid dissolved in dimethyl sulfoxide, and of (b) retinoic acid included in B-cyclodextrin (data adapted from reference [65]).

Figure 8 shows the analytical base-line separation of quebrachamine antipodes by inclusion chromatography on B-cyclodextrin polymers. 

Figure Effect of volume of methanol in the eluent on the retention times of methyl anthraquinone (-0-) and naphthalene (-0-) using a B-cyclodextrin column, 4,6 x 100 mm, and a flow rate of 1 ml/min.

Table IV Effect of column temperature on the retention of dipeptides on a B cyclodextrin column using a mobile phase of 10 Me0H/0.1 M ammonium acetate, pH 5.5...

X-ray crystal structures were used for the production of computer projected images of inclusion complexes of structural isomers, enantiomers and dlastereomers with a- or B-cyclodextrin. These projections allow for a visual evaluation of the interaction that occurs between various molecules and cyclodextrin, and an understanding of the mechanism for chromatographic resolution of these agents with bonded phase chromatography. 

This review will illustrate examples of computer projected models of inclusion complexes of structural isomers (ortho, meta, para nitrophenol), enantiomers (d- and 1- propranolol) and diastereomers [cis and trans. l(p-B-dimethylaminoethoxy-phenyl-butene), tamoxifen] in either a- or B-cyclodextrin. The use of these computer projections of the crystal structures of these complexes allows for the demonstration and prediction of the chromatographic behavior of these agents on immobilized cyclodextrin. 

Figure 3. Computer imaging of the inclusion complexes of d- A) and 1-(B) propranolol with B-cyclodextrin. The chemical structures are illustrated with van der Waals radii shown for only the secondary amine of propranolol and the 2- and 3- hydroxyl groups of the B-cyclodextrin.

Okimoto, K., Rajewski, R. A., and Stella, J. V. (1999), Release of testosterone from an osmotic pump tablet utilizing (SBE)7m-B-cyclodextrin as both a solubilizing and an osmotic pump agent, /. Controlled Release, 58, 29-38. 

Granger, C. E., Feliz, C. P., Parrot-Lopez, H., and Langlois, B. R. (2000),Fluorine containing B-cyclodextrin A new class of amphiphilic carriers, Tetrahedron Lett., 41, 9257-9260. 

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