Cyclodextrin polymer systems

Ammar, H. O., Salama, H. A., Ghorab, M., and Mahmoud, A. A. 2006. Implication of inclusion complexation of glimepiride in cyclodextrin-polymer systems on its dissolution, stability and therapeutic ef cacy. Int. J. Pharm. 320 53-57. 

M. Lahiani-Skiba, C. Barbot, F. Bounoure, S. Joudieh, and M. Skiba, Solubility and dissolution rate of progesterone-cyclodextrin-polymer systems. Drug Dev. Ind. Pharm., 32, 1043-1058, 2006. 

H.O. Ammar, H.A. Salama, M. Ghorab, and A.A. Mahmoud, Formulation and biological evaluation of Ghmepiride-cyclodextrin- polymer systems, Int. J. Pharm., 309, 129-138, 2006. 

A prehminary study of the use of larch AGs in aqueous two-phase systems [394] revealed that this polysaccharide provides a low-cost alternative to fractionated dextrans for use in aqueous two-phase, two-polymer systems with polyethylene glycol (PEG). The narrow molecular-weight distribution (Mw/Mn of 1-2) and low viscosity at high concentration of AG can be exploited for reproducible separations of proteins under a variety of conditions. The AG/PEG systems were used with success for batch extractive bioconversions of cornstarch to cyclodextrin and glucose. 

We also investigated chelate binding by dimers of a synthetic hydrophobic macrocycle, in place ofthecyclodextrins [187]. In the systems examined the chelate effect was weaker than that seen with the cyclodextrin dimers. We also studied the strong binding of cholesterol by some cyclodextrin dimers and a cyclodextrin polymer, and saw that the large sterol could occupy parts of two binding cavities [188]. 

An atypical rotaxane structure is that involving a thread covalently attached to the CyD ring. Such a system acts as both host and guest and it has to be specially designed so that the thread is induded spontaneously in a cavity other than the one bearing it intermolecular inclusion), whereas intramolecular indusion is prevented. The resulting assembly, named a daisy chain by J.F. Stoddart, is either an acyclic supramolecular polymer 8 or a cyclic supramolecular oligomer 9 [50] (Fig. 12.4). Acyclic cyclodextrin polymers were first observed in the solid state in... 

The steric structure of the matrix-carrier can make an additional contribution to the asymmetric reaction, especially if the carrier contains chiral characteristics. Thus, Smith et al. showed that o// / o-cyclodextrin as the host compound can induce asymmetric reactions in the reduction of acetophenone and Tanaka et al. showed that the pyridine-borane-cyclodex-trin system induces chirality with an ee of 91%. Pd supported on a copolymer of Z>eto-cyclodextrin-epichlorhydrin hydrogenates 2-methylpent-2-enoic acid with an ee of 9.3% whereas Pt supported on Z> to-cyclodextrin polymer produced an optical yield of up to 15.7% (Smith et al. 

GOS Gosselet, N.M., Borie, C., Amiel, C., and Sebille, B., Aqueous two-phase systems from cyclodextrin polymers and hydrophobically modified acrylic polymers, J. 

Up to this point, solely low molecular weight alcohols were used nevertheless, polymeric hydroxyl side chains can also be successfully modified. Khan and coworkers used a hydroxyl-containing poly condensate, which was derived from piperazine and 2,2 -[butane-l,4-diylbi(oxymethanediyl)]dioxirane, as starting polymer (Scheme 8) [14]. Tricyclo[3.3.1.1]decane-l-carbolyl chloride could be attached onto these poly(p-hydroxy amines). By acidic treatment, the backbone amine units were protonated and transformed the main chain into a cationic polymer system. The introduced monoadamantyl moiety could then be selectively linked to p-cyclodextrin units to create graft polymers. 

Recently, two examples of the separation of enantiomers using CCC have been published (Fig. 1-2). The complete enantiomeric separation of commercial d,l-kynurenine (2) with bovine serum albumin (BSA) as a chiral selector in an aqueous-aqueous polymer phase system was achieved within 3.5 h [128]. Moreover, the chiral resolution of 100 mg of an estrogen receptor partial agonist (7-DMO, 3) was performed using a sulfated (3-cyclodextrin [129, 130], while previous attempts with unsubstituted cyclodextrin were not successful [124]. The same authors described the partial resolution of a glucose-6-phosphatase inhibitor (4) with a Whelk-0 derivative as chiral selector (5) [129]. 

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