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)

A new binding assay for a protein and its ligand based on a spectroelectrochemical method was demonstrated using avidin-biotin and 17beta-estradiol-antiestradiol antibody. The sensor consists of a selective film coated on an optically transparent electrode (OTE) consisting of indium tin oxide (ITO). Attenuated total reflection (ATR) was used for optical detection. The binding event of the ligand to the protein was detected using the ligand labeled with the electroactive dye Nile blue (NB). The spectroelectrochemical behaviors of NB and the labeled ligand were investigated using various ion-exchange films, such as perfluorosulfonated ionomer (Nafion), Nafion-silica, poly(acrylic acid) (PAA)-silica, poly(styrenesulfonic acid) (PSSA)-silica, and heparin-silica films, which were spin-coated on the ITO electrode. The optical signal was monitored to follow the accumulation of labeled ligand in the film and its electrochemical modulation. The signal from the labeled ligand possesses three modes of selectivity based on charge-selective partitioning, the chosen electrolysis potential, and the particular wavelength for measuring absorbance. The interaction between the labeled ligand and its protein was observed by the decrease in the changes of optical response of the labeled ligand, indicating the specific binding of labeled ligand to the protein.
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PMID:Simultaneous multiselective spectroelectrochemical sensing of the interaction between protein and its ligand using the redox dye Nile blue as a label. 1907 69

In this study, the ability of 7 chemically diverse polymers [Eudragit E100 (E100), poly(acrylic acid) (PAA), poly(vinylpyrrolidone) (PVP), poly(vinylpyrrolidone-vinyl acetate) (PVPVA), poly(styrene sulfonic acid) (PSSA), hydroxypropylmethylcellulose (HPMC) and hydroxypropylmethylcellulose acetate succinate (HPMCAS)] to inhibit the crystallization of 8 readily crystallizable model compounds [benzamide (BD), phenacetin (PH), flurbiprofen (FB), flufenamic acid (FFA), chlorpropamide (CP), chlorzoxazone (CZ), bifonazole (BI) and lidocaine (LI)] was investigated. Films of the different drug-polymer combinations were prepared by rapid evaporation from solution, using a spin coating method. A total of 7 different drug/polymer weight ratios [90/10, 75/25, 60/40, 50/50, 40/60, 25/75 and 10/90 (w/w)] were evaluated for each drug-polymer combination. Crystallization behavior of the films was monitored using polarized light microscopy over 7 days of room temperature storage under dry conditions. It was observed that compounds having a higher crystallization tendency for the pure compound tended to be more difficult to stabilize using the polymeric additives; more polymer was required. In addition, the stabilizing ability of the polymers varied considerably for the individual compounds, with the acidic polymers PAA and PSSA showing the most extreme behavior. The acidic polymers were good stabilizers for the drugs with basic and amide functional groups, but extremely poor stabilizers for acidic drugs. A reasonable correlation between crystallization inhibition in spin coated films versus bulk powders (prepared by rotary evaporation) was observed. The small scale screening method is thus a potentially useful technique to evaluate the role of drug-polymer chemistry in the stabilization of amorphous solid dispersions.
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PMID:Small scale screening to determine the ability of different polymers to inhibit drug crystallization upon rapid solvent evaporation. 2053 63