PREFORMULAITON 2 Flashcards
what are the different solid state forms of a drug?
Crystalline
Chiral
Habits
Amorphous
Definition of a crystalline structure
a crystal is composed of periodical aligned building blocks called unit cells. These unit cells reveal the crystal structure and symmetry specific for each substance. (7 unit cells)
What are the 7 primitive unit cells of a crystalline structure
cubic, tetragonal, trigonal, monclinic, Tricliinic, Hexagonal and Orthorombic
what are molecules that can arrange themselves into 14 different configuration known as?
Bravias Lattices
what crystalline structures does paracetamol exist as?
Exists in two polymorphic forms, monoclinic and orthohombic.
Drugs are usually monoclinic, orthohombic and triclinic
What is crystal form?
Crystal form means ordering of atoms and molecules to form crystal structure, it does not mean outer appearance (habit)
what do we call it when the same chemical compound exists in different crystal forms ?
POLYMORPHISM
what is enantiomorphism?
when chiral molecules crystallise as mirror image of each other
what is crystal habit?
The external shape of a crystal. the crystal habit is associated with the way solute molecules orientate themselves
classes of polymorphs
form 1 and form 2
FORM 1 properties
lower density
lower lattice energy
lower melting point
faster dissolution rate
FORM 2 properties ?
higher density
Higher lattice energy
HIGHER MELTING POINT
Lower bioavailability
what are solid forms hydrates?
formed from organic compounds in the presence of water.
where is hydrate most stable and least soluble?
Most stable solid form in water and least soluble in the GI environment
what are AMORPHOUS solid forms
solid in which there’s no long range order of the positions of moleucles
