title: Block ionomer complexes as prospective nanocontainers for drug delivery.
abstract: Nanosized environmentally responsive materials are of special interest for various applications, including drug delivery. Block ionomer complexes (BIC) composed of graft-comb copolymers of Pluronic and poly(acrylic acid) (Pluronic-PAA) and a model cationic surfactant, hexadecyltrimethylammonium bromide (HTAB), were synthesized by mixing the polymer and surfactant in aqueous media. According to TEM, the resulting BIC represented spherical particles of nanoscale size (50 to 100 nm). The stability of the BIC in the aqueous dispersion depended on the lengths of the hydrophilic poly(ethylene oxide) and hydrophobic poly(propylene oxide) chains in Pluronic molecules as well as on the surface charge of the resulting complexes. The latter was controlled by changing the ratio of the Pluronic-PAA and HTAB in the BIC and by changing the pH due to reversible ionization of the PAA chains. The acidification of the media below pH 6.0 resulted in the appearance of a strong positive charge on the BIC, which in the intracellular environment can trigger interaction of such BIC with the cell membranes. An efficient solubilization of a model hydrophobic molecule, Sudan III, and a drug, Etoposide, in such BIC was demonstrated with the loading capacities of about 6 to 15% by weight of the dispersed complex. Overall, these BIC wield a promise as environmentally responsive nanocarriers for pharmaceuticals.
authors.affiliation: College of Pharmacy, Department of Pharmaceutical Science and Center for Drug Delivery and Nanomedicine, 985830 University of Nebraska Medical Center, Omaha, Nebraska 68198-5830, USA.
authors.forename: Kyung T
authors.initials: KT
authors.lastname: Oh
authors.forename: Tatiana K
authors.initials: TK
authors.lastname: Bronich
authors.forename: Lev
authors.initials: L
authors.lastname: Bromberg
authors.forename: T Alan
authors.initials: TA
authors.lastname: Hatton
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Kabanov
mesh_terms: D000180:Acrylic Resins; D001391:Azo Compounds / Q000737:chemistry; D000077286:Cetrimonium; D002593:Cetrimonium Compounds; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004396:Coloring Agents / Q000737:chemistry; D016503:Drug Delivery Systems; D005079:Excipients; D020100:Hydrogels; D006863:Hydrogen-Ion Concentration; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D049329:Nanostructures; D009391:Nephelometry and Turbidimetry; D010316:Particle Size; D020442:Poloxamer; D012995:Solubility; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
chemical_list: D000180:Acrylic Resins; D001391:Azo Compounds; D002593:Cetrimonium Compounds; D004396:Coloring Agents; D005079:Excipients; D020100:Hydrogels; D008823:Micelles; D020442:Poloxamer; C006903:carbopol 940; C033006:sudan III; D000077286:Cetrimonium