PubMed Health⌕ Search

PubMed · 12384314

Polyanhydrides: an overview.

Abstract

Polyanhydrides have been considered to be useful biomaterials as carriers of drugs to various organs of the human body such as brain, bone, blood vessels, and eyes. They can be prepared easily from available, low cost resources and can be manipulated to meet desirable characteristics. Polyanhydrides are biocompatible and degrade in vivo into non-toxic diacid counterparts that are eliminated from the body as metabolites. Owing to their usefulness, this review focuses on the development, synthesis methods, structures and characterization of polyanhydrides, which will provide an overview for the researchers in the field. Their in vitro and in vivo degradability, toxicity, biocompatibility and applications are discussed in the subsequent chapters of this special issue on polyanhydrides and poly(ortho esters).

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Neeraj Kumar, Robert S Langer, Abraham J Domb. 2002-10-16. Polyanhydrides: an overview.. https://doi.org/10.1016/s0169-409x(02)00050-9

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Efficient preparation of proline N-carboxyanhydride using polymer-supported bases.

[Structure: see text] A procedure for the preparation of proline N-carboxyanhydride in high yield and purity is described using polymer-supported tertiary amines. The polymer-supported amine can be recycled with a basic wash and filtration of the resin. The procedure facilitates the access to the efficient preparation of the polyproline polymer with potential therapeutic interest.

Anhydrides↗

Assessment of 4-nitro-1,8-naphthalic anhydride reductase activity in homogenates of bakers' yeast by reversed-phase high-performance liquid chromatography.

A simple reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed for the simultaneous determination of yield and conversion ratio of 4-nitro-1,8-naphthalic anhydride to 4-amino-1,8-naphthalic anhydride following incubation with a crude bakers' yeast homogenate. The analytes were separated on a C18 column in gradient mode. The detection limit of 4-amino-1,8-naphthalic anhydride is 10ng/microl when using a 10microl sample injection volume. The nitroreductase activity in the homogenate system can be assessed during the bioconversion process. The method can be used for the simultaneous detection of 4-hydroxylamino-1,8-naphthalic anhydride, an intermediate with limited stability.

Anhydrides↗

Mechanism for catechol ring cleavage by non-heme iron intradiol dioxygenases: a hybrid DFT study.

The mechanism of the catalytic reaction of protocatechuate 3,4-dioxygenase (3,4-PCD), a representative intradiol dioxygenase, was studied with the hybrid density functional method B3LYP. First, a smaller model involving only the iron first-shell ligands (His460, His462, and Tyr408) and the substrates (catechol and dioxygen) was used to probe various a priori plausible reaction mechanisms. Then, an extended model involving also the most important second-shell groups (Arg457, Gln477, and Tyr479) was used for the refinement of the preselected mechanisms. The computational results suggest that the chemical reactions constituting the catalytic cycle of intradiol dioxygenases involve: (1) binding of the substrate as a dianion, in agreement with experimental suggestions, (2) binding of dioxygen to the metal aided by an electron transfer from the substrate to O(2), (3) formation of a bridging peroxo intermediate and its conformational change, which opens the coordination site trans to His462, (4) binding of a neutral XOH ligand (H(2)O or Tyr447) at the open site, (5) proton transfer from XOH to the neighboring peroxo ligand yielding the hydroperoxo intermediate, (6) a Criegee rearrangement leading to the anhydride intermediate, and (7) hydrolysis of the anhydride to the final acyclic product. One of the most important results obtained is that the Criegee mechanism requires an in-plane orientation of the four atoms (two oxygen and two carbon atoms) mainly involved in the reaction. This orientation yields a good overlap between the two sigma orbitals involved, C-C sigma and O-O sigma, allowing an efficient electron flow between them. Another interesting result is that under some conditions, a homolytic O-O bond cleavage might compete with the Criegee rearrangement. The role of the second-shell residues and the substituent effects are also discussed.

Anhydrides↗