Characteristics of Solids
- Strong intermolecular forces of Attraction
- Little kinetic energy
- Incompressible
- Fixed/definite shaoe
- Little translational motion
Types of Solids
Crystalline
Amorphous
Polymeric
Arranged in repititious 3-dimensional lattice units
Crystalline Solids
Crystalline solids
Definite melting points
With 7 common lattice units/unit cell
Anisotropic
Cubic
NaCl
Tetragonal
Urea
Orthorhombic
Ritonavir (Form II)
Rhombohedral
Iodine
Hexagonal
Iodoform
Monoclinic
Sucrose
Triclinic
Boric Acid
Amorphous Solid is also called as
“Glasses” or “Supercooled Liquids”
Amorphous Solid
- Randomly arranged particles
- No ordered long-range structure
- Non-crystalline; no definite order
- Have no definite & sharp melting points
- isotropic
Large molecules formed by the covalent assembly of smaller molecules into a chain or network of repeating structural unitd
Polymeric/Polymers
The number of repeating units in the polymer determines its ________ and _______
The number of repeating units in the polymer determines its molecular weight and size of polymer
Polymers are used as ________ in solid, semisolid, and liquid formulations
Polymers are used as excipients in solid, semisolid, and liquid formulations
Types of Polymers
Natural Polymers
Synthetic and Semisynthetic
Natural polymers
Rubber (Polyisoprene)
Polypeptides
Cellulose (Polysaccharide)
Synthetic & Semisynthetic Polymers
PVP
Polyethylene
Polystyrene
LMW PEG
Co-solvent for solution formulations
HMW PEG
Ointment and Suppository Base
Ability to exist in more than one crystalline form
Polymorphism
Polymorphism is due to changes in
Intermolecular bonding patterns
Molecular orientation difference
Polymorphs have different properties
Melting point
Solubilities
Stability
X-ray diffractions
