Viscoelastic properties of pharmaceutical semisolids IV: Destructive oscillatory testing

✍ Scribed by Stanley S. Davis

• Publisher: John Wiley and Sons
• Year: 1971
• Tongue: English
• Weight: 549 KB
• Volume: 60
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.2600600914

✦ Synopsis

Rheogoniometer oscillatory tests of large amplitude were used to simulate the conditions of dermatological usage of semisolid ointments and creams. The onset of nonlinear viscoelastic behavior can be correlated with the yield stress found from continuous shear experiments. The rate of breakdown of viscoelastic structure follows a first-order process and is dependent on the oscillatory frequency and amplitude, product formulation, and, above all, sample thickness. Reformation of structure (thixotropy) was also studied for representative materials. The importance of these tests in product assessment and consumer evaluation is discussed.