Preformulation - Solid State Flashcards
Why are solids important?
Many medicines presented as solid dosage forms
Manufacture of most medicines involve solid ingredients
Solid properties can affect performance of medicines
Solid properties influence formulation decisions
Describe polymorphism
Crystalline solids only
Same chemical substance, different crystal structure
Different molecular arrangement
Functional groups in different ways
What are the different bulk properties?
Melting point Chemical reactivity Optical properties Solubility Dissolution rate Mechanical properties vapour pressure Density
What do bulk properties depend on?
Type, strength + orientation of intermolecular bonds
What is transformation?
One solid form can spontaneously convert to another
What does transformation depend on?
Favourable environmental conditions
What is the stability of metastable crystalline, amorphous + stable crystalline?
Amorphous < metastable crystalline < stable crystalline
What happens to solubility of Amorphous < metastable crystalline < stable crystalline as stability increases?
Decreases
What is the symmetry of Form I of paracetamol?
Monoclinic
What is the symmetry of Form II of paracetamol?
Orthorhombic
What is the stability of Form I of paracetamol?
Stable
What is the stability of Form II of paracetamol?
Metastable
What is the crystallisation of Form I of paracetamol?
Easy
What is the crystallisation of Form II of paracetamol?
Difficult
What is the compactability of Form I of paracetamol?
Low
What is the compactability of Form II of paracetamol?
High
What is the shape of Form I of spironolactone?
Needle-like
What is the shape of Form II of spironolactone?
Prism
What is the melting point of Form I of spironolactone?
205 degrees
What is the melting point of Form II of spironolactone?
210 degrees
What are the crystalline solid properties?
Crystal lattice Regular, repeating molecular arrangement Short + long-range order Defined geometric shape Flat faces (habit) Sharp melting point Thermodynamically stable
What are the amorphous solid properties?
Irregular molecular arrangement Short-range order only NO long-range order, lattice or habit Thermodynamically less stable than crystals No sharp melting points Glass transition temperature