title: Non-covalent nano-adducts of co-poly(ester amide) and poly(ethylene glycol): preparation, characterization and model drug-release studies.
abstract: Biodegradable, biocompatible poly(ester amide)s (co-PEAs), composed of amino acids, fatty diols and carboxylic acids, have been synthesized. To improve the performance of co-PEAs in Federal Drug Administration-approved solvents such as water and ethanol, these polymers were complexed with poly(ethylene glycol) (PEG) of 10 kDa molecular mass have been prepared by solution blending. The non-covalent adducts were purified by precipitation into hexanes. Co-PEAs are soluble in organic solvents but are insoluble in water and ethanol; however, the co-PEA/PEG (0.8:1, w/w) adducts are soluble in ethanol and slightly soluble in water. 2D-NOESY NMR spectroscopy suggests that the non-covalent adducts are held together by multiple non-covalent interactions between the -CH2- groups of the two polymers (co-PEA and PEG). Differential scanning calorimetry studies indicate that the two polymers are interacting in the non-covalent adducts; the thermal properties of the adducts are different from those of the pure polymers. The solid-state adduct structures have been determined by atomic force microscopy (AFM). By one sample preparation method, nanoscale pancake-like structures were observed with an average diameter of 260 nm and an average height of 16 nm. Films of co-PEAs and (co-PEA)/PEG adducts containing Rhodamine B Base (RhBB), a model hydrophobic drug, were prepared. From the adduct/RhBB film containing 3% RhBB, 20% of the total RhBB was released within the first 2 h. Film and adduct composition may be varied to obtain different release profiles. The studies reported here demonstrate that non-covalent conjugation is a relatively easy and effective approach in developing new materials for application as biomaterials.
authors.affiliation: Department of Chemistry, Georgian Technical University, Tbilisi 0175, Georgia, USA.
authors.forename: Irakli
authors.initials: I
authors.lastname: Legashvili
authors.forename: Nino
authors.initials: N
authors.lastname: Nepharidze
authors.forename: Ramaz
authors.initials: R
authors.lastname: Katsarava
authors.forename: Biswajit
authors.initials: B
authors.lastname: Sannigrahi
authors.forename: Ishrat M
authors.initials: IM
authors.lastname: Khan
mesh_terms: D000577:Amides / Q000138:chemical synthesis / Q000737:chemistry*; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry*; D002021:Buffers; D002152:Calorimetry, Differential Scanning; D016503:Drug Delivery Systems; D000431:Ethanol / Q000737:chemistry; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D008970:Molecular Weight; D010710:Phosphates / Q000737:chemistry; D011091:Polyesters / Q000138:chemical synthesis / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D012235:Rhodamines; D012995:Solubility; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D000577:Amides; D001672:Biocompatible Materials; D002021:Buffers; D005456:Fluorescent Dyes; D010710:Phosphates; D011091:Polyesters; D012235:Rhodamines; D014867:Water; D000431:Ethanol; D011092:Polyethylene Glycols; C029773:rhodamine B