Biodegradation cyclodextrin

Drug-Conjugated Biodegradable Cyclodextrin-Based Polyrotaxane... 

Cyclodextrins have ecologically advantageous properties. Not only are they produced from natural and replenishable sources, they are biodegradable, non-toxic and possess no allergenic potential [32,33]. They are commercially available in bulk quantities at an optional degree of purity and have been used for many years in pharmaceuticals. 

In conclusion, it is noteworthy that cyclodextrins, liposomes and chitin derivatives are all readily available from renewable biochemical sources and offer advantages of biodegradability and safety in use. However, it needs to be borne in mind that this fact alone does not necessarily mean that they are entirely environmentally innocuous in the long run. Demands on resources for the husbanding and processing of bioforms that may be necessary in order to sustain demand for commercially viable qualities and quantities can exert deleterious effects, not least because they may give by-products that present problems of utilisation or disposal [70]. 

Main biodegradation products of LAS, sulfophenyl carboxylates (SPCs), were separated by CE using a-cyclodextrin as the chiral selector [6]. The best separation of enantiomers was achieved with 60 mM a-cyclodextrin in a 20 mM citrate buffer at pH 4.0 with an uncoated fused-silica capillary. The method was applied for the qualitative and quantitative analysis of SPC in primary sewage effluents with a detection limit of 1 p,g L-1. 

The reaction was first conducted with success on sucrose [82], The degree of substitution (DS) obtained was controlled by the reaction time. Thus, under standard conditions (0.05% Pd(OAc)2/TPPTS, NaOH (1 M)/iPrOH (5/1), 50 °C) the DS was 0.5 and 5 after 14 and 64 h reaction time, respectively. The octadienyl chains were hydrogenated quantitatively in the presence of 0.8-wt.% [RhCl(TPPTS)3] catalyst in a HjO-EtOH (50/10) mixture, yielding a very good biodegradable surfactant (surface tension of 25 mN m-1 at 0.005% concentration in water) [84]. Telomerization reaction was also conducted with success on other soluble carbohydrates such as fructose, maltose, sorbitol and /i-cyclodextrin. 

Investigating the bioavailability and biodegradation of various organic compounds in the presence of cyclodextrins for in situ environmental applications. 

Evaluating the effect of hydroxypropyl cyclodextrine (HPCD) on phenan-threne solubilization and biodegradation, showing HPCD significantly increased the apparent solubility (i.e., the bio availability) of phenanthrene, having a major impact on the biodegradation rate of phenanthrene [193]. 

One last consideration during the selection process of a suitable surfactant or other facilitating agent must be an examination of toxicity and biodegradability issues so that no adverse impact on the environment or on human health occurs. For example, upon completion of SEAR, any residual HOCs or surfactants remaining in the aquifer should be easily biodegradable or, at minimum, have a relatively low toxicity. Because NOMs and cyclodextrins are naturally-occurring materials, they may have less of an environmental impact than conventional chemical surfactants and may be... 

Chemical modification of both the primary and secondary hydroxyl substituents has been used to further improve their toxicity, water solubility, and biodegradability. Since the hydroxyl groups differ in chemical reactivity, chemical modification typically produces thousands of regio- and stereoisomers resulting in a substantially less crystalline molecule. The amorphous character of chemically modified cyclodextrins has beneficial effects on aqueous solubility and toxicity. Variation of the degree of substitution provides a means for optimizing physical and chemical parameters of the molecules in specific applications. 

Because CDs are nontoxic, biodegradable, and bioabsorbable, they may be used in medical applications, as well as providing for the fabrication of more environmentally responsible polymer materials. In this report we have summarized almost exclusively our own recent studies employing the cyclic starch derivatives called cyclodextrins to both nanostructure and functionalize polymer materials. Lest the reader gets the erroneous impression that our studies have been carried out in isolation, we refer to a recent review [120], and a summary [121], describing related... 

Yui s group has investigated biodegradable polymers based on the cyclodextrin-based polyrotaxanes over the course of the last decade [128-139]. First, they prepared polyrotaxanes from a-cyclodextrin and PEG bisamine (Scheme 23) [128]. For example, l-phenylalanine was employed as an enzymatically hydrolyzable endcap. The in vitro degradation experiments using papain showed that a-cyclo dextrin was indeed released only when the terminal peptide linkages were hydrolyzed. They have prepared various kinds of polyrotaxanes based on cyclodextrin and have demonstrated that these polyrotaxanes are effective as drug delivery systems. 

Yang YK, Tsui CP, Tang CY et al (2010) Functionalization of carbon nanotubes with biodegradable supramolecular polypseudorotaxanes from grafted-poly(E-caprolactone) and a-cyclodextrins. Eur Polym J 46 145-155... 

Journal of Applied Polymer Science 74, No.4, 24th Oct. 1999, p.937-47 FORMATION OF ANTIBIOTIC, BIODEGRADABLE/BIOABSORBABLE POLYMERS BY PROCESSING WITH NEOMYCIN SULFATE AND ITS INCLUSION COMPOUND WITH BETA-CYCLODEXTRIN Lei Huang Taylor H Geiber M Omdorff P E ... 

Cyclodextrins have proven to be the most popular enzyme mimics, catalyzing various reactions. Cyclodextrin-based neoglycoenzymes with improved efficiency have also been designed and synthesized. Cyclodextrin-modified enzymes have potential application as biosensors as well as in the formulation of effective and biodegradable drug delivery systems for enzyme replacement therapy [84]. 

Li, J. Li, X. Ni, X. Wang, X. Li H. andLeong, K. W. Self-assembled supramolec-ular hydrogels formed by biodegradable PEO-PHB-PEO triblock copolymers and a-cyclodextrin for controlled drug delivery. Biomater. 2006, 27, 4132 140. 

Fenyvesi, E, K Gruiz, S Verstichel, BD Wilde, L Leitgib K Csabai and N Szaniszlo (2005). Biodegradation of cyclodextrins in soil. Chemosphere, 60,1001-1008. 

Jianbin, T. Xingping, W. Xinping, W. Meihua, S. Weiwei, M. Youqing, S. p-Cyclodextrin-based biodegradable dendrimers for drug delivery. J. Control. Release 2011, 752 (Suppl. 1), el-el32. 

Kayaman-Apohan, N., Akyiirek, E. Synthesis and drug-release properties of biodegradable hydrogels having -cyclodextrin. 

Over the last decades, several academic and industrial research programs have been focused on the development and production of appropriate biocompatible formulations that provide enhanced therapeutic performance. Three different strategies can be discerned that are applied separately or in combination (i) addition of excipients to proteins, such as protease inhibitors, penetration or absorption enhancers like bile salts, fatty acids, cyclodextrins or surfactants " (ii) modification of the physicochemical properties of proteins, e.g. by attachment of lipophilic or hydrophilic moieties or (iii) incorporation of proteins into polymeric or liposomal delivery carriers. " A variety of polymeric vectors has been developed and exploited for this purpose, including biodegradable nanoparticles, nanogels, micelles, polymer bioconjugates and soluble nanocomposites. These polymeric carriers are more extensively described in the following sub-sections. 

---