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  • 1
    ISSN: 1573-904X
    Keywords: anionic polymer ; rheology ; nonaqueous solvent ; frog palate ; mucociliary transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The influence of formulation variables on the rheology of polyanionic formulations and the relationships between viscoelastic properties and mucociliary transport rate were investigated. Polymeric samples were oscillated from 0.001 to 5 Hz using either a "cone and plate” or a "coaxial cylinder” measuring system. The mucociliary transport rates of polymeric samples were determined and compared movement of charcoal powder on the frog palate. For the linear polymeric solutions, sodium carboxymethylcellulose and sodium alginate, the elastic modulus (G′) increased with increasing amplitudes during frequency scan. However, the G′ or viscous modulus (G″) of partially cross-linked polyacrylic acid (cPAA) samples did not change significantly under oscillation. Both G′ and G″ of cPAA samples were significantly influenced by the amount of salt present in the formulation. The rheology of 2% (w/w) cPAA in 90:10 (w/w) propylene glycol:alcohol changed from a viscous fluid to a coarse suspension after neutralization. The pH increased gradually when the nonaqueous formulation reacted with water and the maximum dynamic moduli were obtained after incorporating 20% (w/w) water in the formulation. A negative correlation was found between the G′ of linear polyanionic samples and the relative transport rate. However, the lowest mucociliary transport rate was observed when the loss tangent (G″/G′) was around 0.4–0.5.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-904X
    Keywords: viscoelastic property ; mucociliary transport ; frog palate ; theoretical modeling of mucociliary transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The effect of viscoelastic properties on mucociliary transport rate was investigated using the frog palate ciliated model. Mucociliary transportability of several hydrophilic polymeric gels with widely different viscoelastic characteristics were tested on the frog palate mucociliary model. An apparent negative relationship is observed between the relative transport rate (TR) and storage (G1) or loss (G2) modulus. However, a minimum in relative transport rate is observed at an apparent loss tangent (tan δ) value of between 0.7 and 0.9. A theoretical model for mucociliary transport is presented. The model predicted a minimum in transport rate at tan δ equal to 1.74 after adjustment for primary variation due to storage modulus (G1) which is in agreement with the observed frog palate transport rate. The model isolates the loss tangent (tan δ) and the magnitude of the complex modulus (|G*|) as the important viscoelastic parameters for mucociliary transport. Optimum rheological characteristics with respect to slow transport rate can be achieved by using hydrophilic polymer gels with a large complex modulus and simultaneously with a loss tangent equal to 1.74.
    Type of Medium: Electronic Resource
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