Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.16.2 (PCP)
 3,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The objective of this study was to evaluate the influence of the molecular mass and accordingly the polymer chain length on mucoadhesion and cohesion of thiolated polymers. Linear poly(acrylic acid)-cysteine (PAA-Cys) conjugates of 2-, 45-, 250- and 450 kDa (PAA(2)-Cys, PAA(45)-Cys, PAA(250)-Cys and PAA(450)-Cys) and polycarbophil-cysteine (PCP-Cys, 750-3000 kDa), all displaying on average 404.1+/-65.5 microMol thiol groups per gram polymer were compressed into tablets to perform disintegration tests, mucoadhesion studies and viscosity measurements. Moreover, the influence of free unbound cysteine on mucoadhesion was evaluated. Disintegration tests showed a stability of the tablets as following: PAA(2)-Cys<PAA(45)-Cys<PAA(250)-Cys<PAA(450)-Cys=PCP-Cys. According to tensile studies and tests on the rotating cylinder the following rank order in mucoadhesive properties could be established: PAA(2)-Cys<PAA(45)-Cys<PCP-Cys<PAA(250)-Cys<PAA(450)-Cys. Evidence for the formation of disulphide bonds between thiolated polymers and mucin could be provided by the addition of free cysteine resulting in strongly decreased mucoadhesion and by viscosity studies showing comparatively higher viscosity of conjugate/mucin mixtures than of unthiolated polymer/mucin mixtures. The results of the present study contribute to the development of new polymers displaying further improved mucoadhesive properties.
 ...
PMID:Mucoadhesive and cohesive properties of poly(acrylic acid)-cysteine conjugates with regard to their molecular mass. 1255 77

The aim of this study was to evaluate the impact of in situ cross-linkers on the gelling and mucoadhesive properties of thiomers. Polycarbophil-cysteine conjugate (PCP-cys) was synthesized by covalent attachment of l-cysteine to polycarbophil via amide bond formation mediated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC) and N-hydroxysuccinimide (NHS) whereas in situ cross-linkers (PAA-cys-MNA) were synthesized by the same bond formation between poly(acrylic acid) (PAA) of 2.1-, 6-, and 15kDa and 2-((2-amino-2-carboxyethyl)disulfanyl)nicotinic acid (cys-MNA) used as ligand. The in situ cross-linking properties were studied via rheological measurements of dynamic viscosity of mixtures of PCP-cys and PAA-cys-MNA with purified porcine intestinal mucus and via rotating cylinder method. The diffusion of polymers in purified porcine intestinal mucus was studied via rotating tube technique. The results showed that in situ cross-linkers (PAA 2.1-, 6-, 15kDa) increase the dynamic viscosity of PCP-cys/mucus mixtures by 5.1-, 5.6-, and 3.5-fold. Combinations of 10% of in situ cross-linkers PAA 2.1-, 6- or 15kDa and 90% PCP-cys increased the adhesion time 1.1-, 2.0- and 4.9-fold, respectively, compared to PCP-cys alone. Diffusion study showed that low molecular mass PAAs highly penetrate into the mucus gel layer due to their high polymer chain mobility compared to PCP-cys. The results provide evidence for the potential of in situ cross-linking agents as gelling and mucoadhesion enhancers.
 ...
PMID:Thiomers: Impact of in situ cross-linkers on mucoadhesive properties. 2854 80