Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0267964 (PAA)
 2,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Formation and stabilization of multiresponsive micelles with a mixed poly(ethylene oxide)/polyelectrolyte shell and a temperature-responsive poly(propylene oxide) core were studied. Various poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers were mixed with poly(acrylic acid)-block-poly(propylene oxide)-block-poly(acrylic acid) (PAA-PPO-PAA) or poly(dimethylaminoethyl methacrylate)-block-poly(propylene oxide)-block-poly(dimethylaminoethyl methacrylate) (PDMAEMA-PPO-PDMAEMA) triblock copolymers. The micelles formed by binary mixtures of well-defined compositions at a specific pH were additionally stabilized by loading with pentaerythritol tetraacrylate (PETA), that was polymerized and cross-linked "in situ" with UV assistance. Depending on both the composition of the copolymers and the experimental conditions, either spherical or wormlike "stabilized polymeric micelles with a mixed shell" (SPMMS) were observed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The SPMMS that contained PAA blocks in the shell were pH-sensitive, such that a reversible transition from well-dispersed SPMMS to precipitate could be promoted. In contrast, the SPMMS with a PEO/PDMAEMA mixed shell remained well-dispersed in the 2-11 pH range. Finally, SPMMS were successfully exploited as templates for the preparation of Ag nanoparticles (Ag NPs).
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PMID:Stabilized mixed micelles with a temperature-responsive core and a functional shell. 1940 18

The purpose of this study was to develop and evaluate the bioadhesivity, in vitro drug release, and permeation of an intravaginal bioadhesive polymeric device (IBPD) loaded with 3'-azido-3'-deoxythymidine (AZT) and polystyrene sulfonate (PSS). Modified polyamide 6,10, poly(lactic-coglycolic acid), polyacrylic acid, polyvinyl alcohol, and ethylcellulose were blended with model drugs AZT and PSS as well as radio-opaque barium sulfate (BaSO4) and then compressed into caplet devices on a tableting press. One set of devices was coated with 2% w/v pentaerythritol polyacrylic acid (APE-PAA) while another remained uncoated. Thermal analysis was performed on the constituent polymers as well the IBPD. The changes in micro-environmental pH within the simulated human vaginal fluid due to the presence of the IBPD were assessed over a period of 30 days. Textural profile analysis indicated that the bioadhesivity of the APE-PAA-coated devices (3.699 +/- 0.464 N; 0.0098 +/- 0.0004 J) was higher than that of the uncoated devices (1.198 +/- 0.150 N; 0.0019 +/- 0.0001 J). In addition, BaSO4-facilitated X-ray imaging revealed that the IBPD adhered to pig vaginal tissue over the experimental period of 30 days. Controlled drug release kinetics was obtained over 72 days. During a 24-h permeation study, an increase in drug flux for both AZT (0.84 mg cm(-2) h(-1)) and PSS (0.72 mg cm(-2) h(-1)) was realized up to 12 h and thereafter a steady-state was achieved. The diffusion and dissolution dynamics were mechanistically deduced based on a chemometric and molecular structure modeling approach. Overall, results suggested that the IBPD may be sufficiently bioadhesive with desirable physicochemical and physicomechanical stability for use as a prolonged intravaginal drug delivery device.
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PMID:Investigation of the physicochemical and physicomechanical properties of a novel intravaginal bioadhesive polymeric device in the pig model. 2044 71

The electrostatic complexation between lysozyme and stabilized polymeric micelles (SPMs) with a poly(acrylic acid) (PAA) or a mixed poly(ethylene oxide)/poly(acrylic acid) (PEO/PAA) shell (SPMs with a mixed shell, SPMMS) and a temperature-responsive poly(propylene oxide) (PPO) core was investigated by means of dynamic, static, and electrophoretic light scattering. The SPMs and different types of SPMMS used resulted from the self-assembly of PAA-PPO-PAA triblock copolymer chains, or PAA-PPO-PAA and PEO-PPO-PEO triblock copolymer chain mixtures (with varying chain lengths and molar ratios) in aqueous solutions at pH 10 and the subsequent cross-linking of their PPO cores via loading and photo-cross-linking of pentaerythritol tetraacrylate (PETA). The solution behavior, structure and properties of the formed complexes at pH 7 and 0.01 M ionic strength, were studied as a function of the protein concentration in the solution (the concentration of the stabilized micelles was kept constant) or equivalently the ratio of the two components. The complexation process and properties of the complexes proved to be dependent on the protein concentration, while of particular interest was the effect of the structure of the shell of the SPMs on the stability/solubility of the complexes. Finally, the fluorescence and mid infrared spectroscopic investigation of the structure of the complexed protein showed that, although a small stretching of the protein molecules occurred in some cases, no protein denaturation takes place upon complexation.
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PMID:Complex Formation Between Lysozyme and Stabilized Micelles with a Mixed Poly(ethylene oxide)/Poly(acrylic acid) Shell. 2688 45