Application of dynamic mechanical testing to characterize the viscoelastic properties of powder-filled semisolids

• Published in: Journal of pharmaceutical sciences 1984-05, Vol.73 (5), p.590-594
• Main Authors: Radebaugh, Galen W., Simonelli, Anthony P.
• Format: Article
• Language: English
• Subjects: application to the viscoelasticity of powder-filled semi-solids; Biological and medical sciences; Chemical Phenomena; Chemistry, Pharmaceutical; Chemistry, Physical; dynamic mechanical testing; Dynamic mechanical testing-viscoelastic properties of powder-filled semisolids; Dynamic mechanical testing—viscoelastic properties of powder‐filled semisolids, starch‐anhydrous lanolin model, Kerner equation; Elasticity; General pharmacology; Kerner equation; Kerner equation-dynamic mechanical testing; Kerner equation—dynamic mechanical testing, application to the viscoelasticity of powder‐filled semi‐solids, starch‐anhydrous lanolin model; Lanolin; Medical sciences; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Powders; Starch; starch-anhydrous lanolin model; Temperature; Viscoelasticity-powder-filled semisolids; Viscoelasticity—powder‐filled semisolids, starch‐anhydrous lanolin model, dynamic mechanical testing, Kerner equation; Viscosity
• ISSN: 0022-3549; 1520-6017
• DOI: 10.1002/jps.2600730504

A nondestructive technique, dynamic mechanical testing, was used to characterize the viscoelastic properties of dispersions of powdered starch in anhydrous lanolin. The elastic shear modulus (G'), viscous shear modulus (G'), and loss tangent (damping; tan δ) were determined as a function of shear frequency, temperature, and the volume fraction of starch. The results of these studies show that constitutive mathematical models, derived to predict the mechanical behavior of solid‐filled polymeric materials, can be applied to solid‐filled semisolid Pharmaceuticals. In particular, the Kerner equation was useful in describing the influence of starch on the G′ of the dispersions. Even though the Kerner equation was unable to predict viscoelastic behavior at all shear frequencies, temperatures, and starch volume fractions, it proved beneficial in postulating mechanisms for starch‐starch and starch‐anhydrous lanolin interactions within the dispersions. In addition, damping was able to differentiate the influence of temperature. Data obtained from three temperature ranges, where anhydrous lanolin exists in three different structural states, shows that the influence of starch on damping is dictated by the structural state of anhydrous lanolin.