state of matter

Cohesion

attraction of like molecules

Adhesion

attraction of unlike molecules

Attractive forces

are necessary in order that molecules cohere/adhere

Repulsive forces

necessary in order that the molecules do not interpenetrate one another.

Van der Waals Forces • Keesom Forces

• Orientation Effect • Attraction between polar molecules • Strongest

Van der Waals Forces • Debye Forces

• Induction effect • Attraction between nonpolar and polar molecules

Van der Waals Forces • London Forces

• Attraction between nonpolar molecules • Weakest

Ion-induced dipole forces

• Attractions occur between nonpolar molecules and ions.
• Ion- induced dipole forces are involved in the formation of the iodide complex.
• These types of interactions account in part for the solubility of ionic crystalline substances in water

Ion-Dipole Forces

Attractions occur between polar molecules and ions

Hydrogen Bonding

It is a special type of dipole-dipole in which hydrogen is bonded to an electronegative element.
It can exist as Intramolecular and Intermolecular forces of attraction.

. Hydrophobic Interactions

Forces of attraction between non-polar atoms and molecules in water.

sublimation

solid to gas

evaporation

liquid to gas

deposition

gas to solid

total pressure (Pt)

the sum of the individual partial pressure of each component in the system.

Kinetic Molecular Theory

The theory developed to explain the behavior of gases and supported the validity of the gas laws

Critical Temperature

maximum temperature, above which a liquid can no longer exist

374°C or 647°K,

Critical Temperature of water

218 atm

critical pressure value

Critical Pressure

pressure required to liquefy a gas at its critical temperature, which is also the highest vapor pressure that the liquid can have.

Adiabatic expansion

an expansion which allows an ideal gas to expand so rapidly that no heat enters the system.

Joule – Thomson effect

This cooling effect is observed when a highly compressed non-ideal gas expands into a region of low pressure. In this case, the drop in temperature results from the energy expended in overcoming the cohesive forces of attraction between the molecules.

Aerosols

The basic principle involved in the preparation of pharmaceutical aerosols is when pressure is reduced, the molecules expand and the liquid revert to a gas.

Propellant

A material that is liquid under the pressure conditions existing inside the container but that forms a gas under normal atmospheric conditions.

Equilibrium Vapor Pressure

When the rate of condensation equals the rate of vaporization at a definite temperature, the vapor becomes saturated and a dynamic equilibrium is established.
• It is the pressure of the saturated vapor above the liquid

Vapor

is a substance that is liquid or solid at room temperature and that passes into the gaseous state when heated to a sufficiently high temperature

Manometer

device used to measure the vapor pressure

Crystalline Solids

Are substances whose constituent atoms, molecules, or ions are arranged in an ordered or arranged in repetitious 3 dimensional lattice units infinitely throughout the cell.

• The nature of unit cells has different properties such as solubility, stability and compressibility.

• The macroscopic crystals can have different geometric shape such as plates, needles, blades, prisms and blocks.

Crystalline Solids

They are anisotropic

Four types of Units Cells (crystalline solids)

o Primitive (P)
o Body centered (I)
o Face centered (F)
o Side centered (C)

Enantiotropic

If one of the polymorph is the most stable over a certain temperature range while the other polymorph is the most stable over a different temperature range below the melting point

reversible

Monotropic

If one polymorph is ALWAYS the most stable for all temperatures below the melting point, with all the other polymorphs being less stable.

• Gamma form • Alpha form • Beta prime form • Beta stable form

4 polymorphs

Gamma form

18 deg celsius, least stable form

Alpha form

22 cel =, unstable in room temp

Beta prime form

28 c moderately stable

Beta stable form

34.5, most stable form

Pseudopolymorphs

• Solvents are trapped within a crystal lattice structure through crystal engineering. • Solvents could be water or other solvents. • The water/solvent is usually present in stoichiometric ratios.

Salt Crystals

form when drug substance react in acid or base to create new crystalline structure
• Aside from solvents, crystal lattice can accommodate other molecules, such as acids and bases, to form salts.
• If there is a pKa difference of two between the molecules, a proton is transferred to form two ionized species.

coformer

used to improve or after the physicochemical properties of API without changing the drug’s molecular structure

Co-Crystals

They contain two or more distinct molecules arranged to create a new crystal form whose properties are often superior to those of each of the separate entities.
• The pharmaceutical cocrystals are formed between a molecular or ionic drug and a cocrystal former that is a solid under ambient conditions

Amorphous Solids

May be considered as super cooled liquids in which the molecules are arrange in a random manner somewhat as in the liquid state. • Examples: coal, glass, plastic and rubber

Liquid Crystalline State

They are the fourth state of matter. • They can be formed by heating solids or the action of certain solvents

nematic phase

parallel

smectic phase

layers

cholesteric phase (chiral nematic phase)

directional and stack in helical pattern

discotic phase (columnar phase)

disc shape

• Apatone • Olecine

Latest development in Liquid crystalline technology

J. Willard Gibbs the Phase rule

It is a useful device for relating the effect of the least number of independent variables (temperature, pressure, and concentration) upon the various phases (solid, liquid, gas) that can exist in an equilibrium system containing a given number of components. • The phase rule is expressed as follows: F = C – P + 2

Phase Rule

how changes in variable like temperature affect different phase in system