BIOL 2020 Chapter Notes - Chapter 7: Wetting, Hovercraft, Excipient
20 Apr 2020
School
Department
Course
Professor
Document Summary
Smaller, hydrophobic particles float on top of water: we want to wet powder so it can dissolve. For hydrophobic drugs, we can add exceipient to increase wettability, then compress. Macrosetae are scored with grooves measured in nanometers. Air gets trapped in spaces amount macrosetae to from air cushion which prevents legs from getting wet water repellence. Thus tablets & drugs need to be wettable in order to dissolve. If drug is insoluble, need to add excipient. Dissolution as limiting factor: dissolution is a limiting factor that influences bioavailability. Larger drugs slow to dissolve lower ba. Particles must not be too fine as flowability will decrease. Fine particles have poor flowability compared to larger particles: when preparing suspension, we need to pay attention to particle size, rate of sedimentation is related to viscosity of vehicle & particle size. Suspensions could result in particles settling at bottom. Topical formulations, ointments contain solid particles mixed w/base.
