REDS :( Flashcards
What is potential energy?
Energy by virtue of position
What is P (partition coefficient)
Its applied to solid equilibriums, used to work out gibbs at 0
Define solution
Mixture of two or more components that form a single homogenous phase at the molecular level
Steps of dissolution process
- Drug molecule liberated from surface areas of particle
- Drug concentrated in solution at surface
- Solute migrates through boundary layer to bulk liquid by diffusion or convection
- Local concentration of drug drops as it migrates from boundary layer
Consequences of drug being too hydrophobic (too lipophilic) or hydrophilic
- If a compound is too lipophilic, it may be insoluble in aqueous media, it means it may bind too strongly to plasma proteins and therefore blood conc will be too low to have desired effect
- If its too polar it may not be absorbed through gut due to lack of membrane solubility
- SO its important lipophilicity of drug is known, we measure this using LogP
Name some excipients used
Name three different types of polyelectrolytes
- Polymers having ionisable functional groups
- Sometimes we might ionise it to for form this because it may have better properties e.g. soluble in water
What is the isoelectric point (IEP)
IEP is the pH at which the effective net charge on a macromolecule is zero
The different molecular structure/conformation of macromolecules in solution
Define and the equation of Rheology
Rheology is the study of flow and deformation of properties of a matter
Viscosity of a polymer in thermodynamically good solvent is LOWER OR HIGHER compared to the viscosity in thermodynamically poor solvent
HIGHER
In relatively concentrated solutions the viscosity of polymers depends on the BLANK (non-Newtonian)
In relatively concentrated solutions the viscosity of polymers depends on the shear stress (non-Newtonian)
Polymers can be precipitated from solutions upon addition of a BLANK
Polymers can be precipitated from solutions upon addition of a non-solvent
In solutions macromolecules can change their conformations in response to the changes in BLANK
In solutions macromolecules can change their conformations in response to the changes in environmental conditions
Three things to add to stabilise a suspension (pd or emulsion)
- ADD Electrolyte concentration - These create an electric double layer, leading to electrostatic repulsion between particles. This prevents particles from aggregating or settling
- ADD Surfactants: reduce interface tension between two phases - prevents seperation
- ADD hydrophilic polymer - cause steric hind, increase viscosity and wetting agents