Week 7 solids solutions and size Flashcards
States of matter / phases
Solid, liquid, vapour (gas), plasma
Phase diagram, allows you to pinpoint what state a substance will be in at a specific temprature
Sublimation, where a substance moves from being a solid directly to being a gas
Triple point -> temperature and pressure where all three phases are existing in equilibrium
Critical point -> Point on temperature and pressure line where there are no clear boundaries between liquid and gas
Pharmaceutical solids
Can broadly exist in two forms, a crystalline form and an amorphous form
Crystalline form
All solids in a very ordered crystalline tructure
-Polymorphs
-Solvates and hydrates
-Co-crystals
Polymorphs
Different arrangements of the molecule, still crystalline structure but a slightly different crystalline structure, still has a very rigid order
Solvates / hydrates
Still solids but a solvent molecule has become incorporated into the crystalline structure, can get different arrangements of solvates with different numbers of water molecules per drug molecule - when that solvent is water we refer to it as a hydrate rather than a solvate
Co-crystals
Solids that are crystalline materials that are composed of two or more molecules in the same crystalline lattice
Amorphous
Solids that have no fixed arrangement, no defined order of arrangement of the individual molecules
Polymorphism
Where crystals formed by a single molecular species take different forms
The structure of these forms is dependent on the intermolecular attractions between molecules
We may use the term isoform to refer to polymorphic structures
Genetic equivalents
When a drug is first launched there will be a branded product made by the pharmaceutical company that has developed that product. The product will have a patent protecting that drug, which means no one else can profit off that particular new drug, only the company that made it can do it
When that patent expires, it means that any company can make that drug formulation and start selling it -> these are referred to as the generic equivalent product
Solution
Mixture of two or more components that form a single phase that is homogenous to the molecular level
Solvent
The component that determines the phase (usually present is the greatest quantity and typically a liquid)
Solute
The other component(s) which are dispersed as molecules / ions throughout the solvent - these components are in solution
Dissolution
The process whereby molecules or ions from the solid phase move into solution
Solution -> single phase system
Suspension / emulsion -> two - phase
Saturated system
If you keep adding solute to the solution there will reach a point where that drug will stop entering solution -> equilibrium is reached where no more solute can dissolve
Equilibrium is dependent on the conditions
Solid in liquid solutions
1)Solutions of non-electrolytes (non-ionic)
->Does not conduct an electric current, is not being broken down into charged ions
2)Solutions of electrolytes
->Will split into its ions upon dissolution, will conduct an electric current
-Strong electrolytes - fully ionise over a wide pH range
- Weak electrolytes - ionisation dependent on pH
Liquid in liquid solutions
1)Completely miscible
Miscibility -> mutual solubility of components in liquid-liquid systems
2)Partially miscible
-Affected by temperature
-Partially miscible binary liquids are used with a separating funnel to determine partition coefficients
Gas in liquid solution
Solubility of gases is determined by temperature and pressure
Solubility generally decreases as temperature rises
Different to a solid, typically with solids as you increase temperature solubility increases
Solubility generally increases with pressure in gases
Water for injections
Water for injections is the name for a particular ingredient that is often used when we are preparing injections
Want to make sure there is limited gas dissolved in the water for injections so it is important to ensure heat is considered
