Tablet Behaviour Flashcards
Unit Cell Def
Simplest repeat unit in a crystal
Crystal Habit Def
Shape of drug crystal, observes by visual inspection
Crystal Lattice Def
3D arrangement of unit cells. Permits optimal attractive interactions between particles in a solid
Amorphous Solid Def
No patterns in solid. No distinguishable crystal lattices. More soluble and less stable
Polymorphism Def
Crystals that contain more then 1 pattern. Effects properties eg; dissolution rate, surface free energy, hygroscopicity and molecular volume/density
Anhydrous Def
Crystal without water in it’s structure
Solvate Def
Crystal with solvent in it’s structure
Hydrate Def
Crystal with water in it’s structure. Dissolves faster
Solid State Analytical Technique Bulk
Microscopy, Differential Scanning Calorimetry (heat) and Thermogravimetric Analysis (thermal)
Solid State Analytical Molecular Techniques
IR spectroscopy, nuclear magnetic resonance and powder x-ray diffraction
Calorimetry Outline
Heat transfers during physical and chemical processes. Measures physicochemical properties in relation to temp change
Differential Scanning Outline
Sample and reference heated at the same time at constant rate. Instrument measures amount of energy needed. Records: endo/exothermic, melting, recrystallisation and glass transitions
X Ray Diffraction Outline
How an xray is spread out when passing through a sample. Follows Bragg’s Law
Powder X Ray Diffraction Outline
Polymorph ID gold standard. Unit cells have different refractions, each having a unique finger prints
Does anhydrates or hydrates have better division
Anhydrates are more structured, better solubility and betetr packing
Tableting Considerations
Large amount of energy can disrupt physical structure. Increase amorphous/polymorph formation. Amorphous forms when substance cools to fast to restructure
Process Examples
Milling (particle size reduction), drying (spray/freeze) and granulation (wetting, grinding)
