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Comparative Rheological Characterization of Two Natural Polymers from Sesamum radiatum and Bombax buonopozense for Application in Drug Delivery
Author(s) -
Ngwuluka Ndidi,
Nep Elijah,
Ochekpe Nelson,
Odumosu Patricia,
Olorunfemi Patrick
Publication year - 2014
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.201400064
Subject(s) - rheology , sesamum , shear thinning , materials science , polymer , composite material , horticulture , biology
Summary Small deformation measurements have been used to characterize the rheological behaviour of two understudied natural polymers obtained from the leaves and calyxes of Sesamum radiatum and Bombax buonopozense respectively, by extraction with water, and then precipitation with absolute ethanol. Measurements performed on 1% w / v aqueous dispersion of each polymer at ambient conditions include viscosity, yield stress, oscillatory stress sweep, oscillatory frequency sweep, creep and recovery, and then temperature ramp. The measurements were done on the same samples on the first day and fourth day after storage at ambient temperature. The polymers exhibited shear‐ thinning with the viscosity of bombax gum remaining basically same on the 1 st and 4 th day while sesamum gum had a significant drop in viscosity by the 4 th day. Bombax gum (yield value – 5.499 Pa at shear 0.114 s −1 ) had more internal strength than sesamum gum (yield value – 0.338 Pa at shear 0.032 s −1 ). In addition, bombax gum exhibited more elasticity and extended visco‐elastic region than sesamum gum. The present study suggests that bombax gum can be used for matrices and hydrogels with improved physicomechanical strength and sustained drug release while sesamum gum may require modification to achieve similar properties.