This document discusses the different states of matter - solids, liquids, and gases. It describes the key properties of each state, including how the particles are arranged and how they move. It then focuses on solids, explaining that solid particles are tightly packed and vibrate about a fixed position. The document discusses crystalline and amorphous solids, polymorphism, crystal structures, crystal growth, and precipitation. It provides examples to illustrate these concepts and differences between solid state forms that can impact a drug's therapeutic properties.
3. STATES OF MATTER
SOLIDS
•Particles of solids are
tightly packed,
vibrating about a fixed
position.
•Solids have a definite
shape and a definite
volume.
4. STATES OF MATTER
LIQUID
Particles of liquids
are tightly packed,
but are far enough
apart to slide over
one another.
Liquids have an
indefinite shape
and a definite
volume.
5. STATES OF MATTER
GAS
Particles of
gases are very
far apart and
move freely.
Gases have an
indefinite shape
and an indefinite
volume.
6. Solid
refers to the state of matter in which the particles
are locked into place without much freedom of
movement. They can be locked into crystal
lattices or just kind of stuck together with
intermolecular forces so tightly that they can’t
really move around.
Solids differ from liquids in that the particles in
liquids, while still stuck together, do have some
freedom of motion.
Solids differ from gases in that gas molecules really
don’t interact with each other much, flying all over
the place
7. PHASE CHANGES
Description of
Phase Change
Term for Phase
Change
Heat Movement During
Phase Change
Solid to
liquid
Melting
Heat goes into
the solid as it
melts.
Liquid to
solid
Freezing
Heat leaves the
liquid as it
freezes.
8. PHASE CHANGES
Description
of Phase
Change
Term for Phase
Change
Heat Movement During
Phase Change
Liquid to gas
Vaporization,
which includes
boiling and
evaporation
Heat goes into the
liquid as it vaporizes.
Gas to liquid Condensation
Heat leaves the gas as
it condenses.
Solid to gas Sublimation
Heat goes into the
solid as it sublimates.
9. STATES OF MATTER
SOLID LIQUID GAS
Tightly packed, in a
regular pattern
Vibrate, but do not
move from place to
place
Close together with
no regular
arrangement.
Vibrate, move
about, and slide
past each other
Well separated with
no regular
arrangement.
Vibrate and move
freely at high
speeds
10. 10
What is solid…..to pharmacy?
Majority of drugs and excipients exist as solids
Various dosage forms are prepared
e.g. tablets, emulsions
13. 13
Crystal Structure
• Crystals contain highly
ordered molecules or
atoms held together by
non-covalent
interactions
• E.g. NaCl has the cubic
structure
14. 14
Can be defined on the basis of
variations on the themes of 7 systems
Types of Crystal Structure
1. Cubic
- sodium chloride
2. Tetragonal
- urea
3. Hexagonal
- iodoform
4. Rhombic
- iodine
5. Monoclinic
- sucrose
6. Triclinic
- boric acid
7. Trigonal
15. 15
Angles & lengths that describe crystal habit
α = between length & breadth
β = between breadth & height
γ = between length & height
Crystal Angle of axes Length of axes Examples
Cubic (regular) α = β = γ = 90º x =y =z NaCl
Tetragonal α = β = γ = 90º x =y ≠z NiSO4
Orthorhombic α = β = γ = 90º x ≠y ≠z K2MNO4
Monoclinic α = β = γ ≠ 90º x ≠y ≠z Sucrose
Triclinic (asymmetric) α ≠β ≠ γ ≠ 90º x ≠y ≠z CuSO4
Trigonal (rhombohedral) α = β = γ ≠90º x =y =z NaNO3
Hexagonal Z at 90º to base - AgNO3
20. 20
Bravais Lattices
1. End-centred
i. Monoclinic
ii. orthorombic
2. Face-centred
i. Cubic (NaCl)
ii. Orthorombic
3. Body-centred
i. Cubic tetragonal
ii. Orthorombic
Total of 14 possible
types of unit cells
For drugs, only 3 types:
1. Triclinic
2. Monoclinic
3. Orthorombic
21. 21
FCC Structure of NaCl
• Small spheres
represent Na+ ions,
large spheres
represent Cl- ions.
• Each sodium ion is
octahedrally
surrounded by six
chloride ions and
vice versa.
22. 22
Crystallisation
Crystallisation steps from solution:-
1. Supersaturation of the solution
e.g. cooling, evaporation, addition of
precipitant or chemical reaction
2. Formation of crystal nuclei
e.g. collision of molecules, deliberate
seeding
3. Crystal growth around the nuclei
23. 23
Crystal Growth
Steps involved:
1. Transport of molecules to the surface
2. Arrangement in the lattice
Degree of agitation in the system affects the
diffusion coefficient, thus affects crystal
growth.
24. 24
Precipitation
1. Induced by altering pH of solution to reach
saturation solubility.
2. By chemical reaction to produce precipitate from a
homogeneous solution.
The rate of reaction is important in determining
habit.
25. 25
Crystallization from Supersaturated Solutions
of Sodium Acetate
• Description: A supersaturated
solution of sodium acetate is
crystallized by pouring it onto a
seed crystal, forming a stalagmite-
like solid. Heat is radiated from the
solid.
26. 26
Polymorphisms
• When compounds crystallise as different
polymorphs, properties change.
• Molecules arrange in two or more ways in the
crystal: packed differently in crystal lattice,
different orientation, different in
conformation of molecules at lattice site.
• X-ray diffraction patterns change.
27. 27
Polymorphism of Spironolactone
• A diuretic (no potassium loss)
• 2 polymorphic forms and 4 solvated crystalline
• Form 1: spironolactone powder is dissolved in
acetone at a temperature near boiling point
and cooled to 0 deg. C within a few hours –
needle-like
• Form 2: powder dissolved in acetone or
dioxane or chloroform and acetone allowed to
evaporate for several weeks – prism
29. 29
Amorphous Solids
• E.g. silica gel, synthetic plastics/polymers
• Irregular shape
- molecules are arranged in a random manner
• No definite melting point
- no crystal lattice to break
• Exhibit characteristic glass transition temperature, Tg
• Flow when subject to pressure over time
• Isotropic i.e. same properties in all direction
• Affect therapeutic activity e.g. amorphous antibiotic
novobiocin is readily absorbed and therapeutically active
compared to the crystalline form
