Preformulation of Solid Dosage Forms Flashcards
What is the aim of a dosage form?
To facilitate the delivery of Therapeutic Drugs
What is a preformulation?
The first step in the ‘rational approach’ to developing a drug into a medicine
What must a dosage form be?
Safe
Efficient
Reproducible
Convenient
What does In-vivo mean?
In a living organism
What does In-vitro mean?
In a lab environment
What is a preformulation exercise?
generates mathematical and statistical data, that helps the development of a dosage form.
What is the aim of a preformulation exercise?
To create a mathematical model for drug behaviour in the dosage form being studied.
If a drug is given by GI…
The drug MUST permeate the gut epithelium
Controlling factors of GI dosage forms
dissolution and solubility
Optimal solubility for GI dosage forms
10mg/ml
What should be done if the solubility is less than 1mg/ml
Put in a salt form
How do you determine the dissolution rate
Noyes Whitney equation
Is Solubility a Constant or a Variable
Constant
Is dissolution a constant or variable
Variable
What affects dissolution rate?
diffusion layers
concentration of drug solution
How many classes are in the Biopharmaceutical Classification?
4 Classes
Which Biopharmaceutical Class has high solubility, high permeability?
Class 1
Which Biopharmaceutical Class has high solubility low permeability?
Class 3
Which Biopharmaceutical Class has low solubility, high permeability?
Class 2
Which Biopharmaceutical Class has low solubility and low solubility
`Class 4
How are drugs with low solubility described
Brick Dust
How to fix low solubility?
Make it a Salt
Polymorph (change the structure)
Reduce the particle size
When do you convert a drug to its salt?
When it has a poor aqueous solubility
it is a weak acid
Or a weak base
The equation to find the pH of a drug?
Henderson Hasselbach Equation
What are the solid-state forms?
Crystalline, Chiral, Habits, Amorphs.
What does the physical form of the Drug affect?
performances,
development
patentability
manufacturing
profitability
What are the 3 most common primitive structures
monoclinic
triclinic
orthohombic
What is enantiopolymorphism?
Changing a chiral crystalline form to its enantiomer
What is pseudopolymorphism?
When solvent molecules form a crystal lattice
What does enantiotropic mean?
Reversible transitions to a different form that does not undergo a phase change.
What does monotropic mean?
Irreversible transitions to a different form that undergo a state change first,
What does changing polymorphic form affect?
Melting point
Density
Stability
Compressibility
and more
Where are hydrates most stable?
Water
Where are hydrates least stable?
GI environment
What are the 3 types of Amorphous forms?
Solid, Lipophillized, Oral Fast dissolving Tablets
