ABSTRACT
The octet-compliant group 13 organometallics with highly polarized bonds in the metal coordination sphere exhibit a significant tendency to maximize their coordination number through the formation of adducts with a wide range of neutral donor ligands or by self-association to give aggregates containing tetrahedral and higher coordinated aluminium centres, and even in some cases molecular complexes equilibrate with ionic species of different coordination numbers of the metal centre. This work provides a comprehensive overview of the structural chemistry landscape of the group 13 carboxylates. Aside from a more systematic approach to the general structural chemistry of the title compounds, the structure investigations of [R2M(µ-O2CPh)]2-type benzoate complexes (where M = B, Al and Ga) and their Lewis acid-base adducts [(R2M)(µ-O2CPh)(py-Me)] are reported. DFT calculations were also performed to obtain a more in-depth understanding of both the changes in the bonding of group 13 organometallic carboxylate adducts with a pyridine ligand.
ABSTRACT
The polyester- and poly(ester-carbonate)-paclitaxel conjugates with low molecular weight were synthesized using dicyclohexylcarbodiimide (DCC) and dimethylaminopyridine (DMAP) as catalysts. Polymeric matrices were obtained by ring-opening polymerization of É-caprolactone (CL), rac-lactide (rac-LA), l-lactide (LLA) and trimethylene carbonate (TMC). The macromolecular conjugates were characterized by using spectroscopic techniques, such as (1)H, (13)C NMR and FTIR. The degree of degradation of polyester- and poly(ester-carbonate)-paclitaxel conjugates was tested in vitro under different conditions. The preliminary results of drug release were discussed.
Subject(s)
Antineoplastic Agents, Phytogenic/chemistry , Dioxanes/chemical synthesis , Drug Carriers , Paclitaxel/chemistry , Polyesters/chemical synthesis , Caproates/chemistry , Catalysis , Delayed-Action Preparations , Dicyclohexylcarbodiimide/chemistry , Dioxanes/chemistry , Drug Liberation , Lactones/chemistry , Pyridines/chemistryABSTRACT
The controlled release of 5-fluorouracil (5FU) from aliphatic poly(amide urethane)s (PURs) was studied in vitro. Linear PUR conjugates were prepared by the reaction between oligo(É-caprolactone) (PCL), oligolactide (PLA), copolymers of É-caprolactone (CL) and rac-lactide (rac-LA), dihydroxy(polyethylene adipate) (OEDA) with 1,6-diisocyanatohexane (HDI). Release of 5FU from PURs was found to depend on the nature of oligoester units and consist of soft and hard segments.
Subject(s)
Antimetabolites, Antineoplastic/administration & dosage , Delayed-Action Preparations/chemistry , Fluorouracil/administration & dosage , Polyurethanes/chemistry , Antimetabolites, Antineoplastic/chemistry , Fluorouracil/chemistryABSTRACT
New polymeric conjugates were prepared coupling ofloxacin to two-, three-, four and six-arm, star-shaped poly(É-caprolactone) and polylactide. The homopolymers were synthesized via ring-opening polymerization of É-caprolactone, l-lactide and rac-lactide in the presence of glycerol, penthaerythritol, dipentaerythritol and poly(ethylene glycol) as initiators and stannous octoate as a catalyst. The conjugates were characterized by GPC, MALDI-TOF MS, NMR, IR and viscosity methods. Content of Sn has been investigated in polymers by electrothermal atomic absorption spectrometry. Toxicity of monomers, initiators and polymers were evaluated with bacterial luminescence test and two protozoan assays. The in vitro release of ofloxacin from obtained conjugates in pH 7 was investigated.
