pharmaceutical chemistry, Subject- process chemistry topic- Crystallization from Aqueous and Non-aqueous solvent

1. Crystallization from Aqueous, Non-aqueous Solutions
Presented by
• Kamal Lochan Misra
• Roll No. 2208257020
• M. Pharm 2nd Semester
• Department of Pharmaceutical Chemistry
• Institute of Pharmacy and Technology, Salipur,
Cuttack

2. CONTENT
 Introduction
 Types of Solid Forms
 What is Crystallization
 Importance of Crystallization
 Crystallization from Aqueous Solution
 Crystallization from Non-aqueous
Solution
 Factors Affecting Crystallization

4. Crystals
 Crystals can be defined as a solid particle, which is formed by the solidification process under
suitable environment in which structural units are in which, structural units are arranged by a
fixed geometric pattern or lattice.
 The smallest geometric portion, which repeats to builds of the whole crystal is called a unit
cell.

7. Introduction
 Crystallisation is a chemical solid-liquid separation technique in which, mass transfer of solute
from a liquid
solution to the pure solid.
 It is a spontaneous arrangement of the particles into a repetitive orderly array like, regular
geometric pattern.
 Technique used to purify solid compound.

8. What is Crystallization ?
Crystallization is the process of atoms or molecules arranging into a well-defined, rigid crystal lattice in
order to minimize their energetic state. the smallest entity of a crystal lattice is called a unit cell, which
can accept atoms or molecules to grow a macroscopic crystal.
During crystallisation, atoms and unit cells bind together with well-defined angles to form a
characteristic crystal shape with smooth surfaces and facets.
Crystallization can occur in nature but also has broad industrial applications as a separation and
purification step in the pharmaceutical, chemical and food industries

10. Importance of Crystallization
 Purification of Drugs.
 To improve bioavailability of drug and choose the most stable form.
 A crystalline powder is easily handled, stable, possesses good flow properties and an attractive
appearance.
 Crystallization of a solution is important industrially because of the variety of materials that are
marketed in crystalline form.
 Crystallization afford a practical method of obtaining pure chemical substances in a satisfactory
condition for packaging and storing.

11. Crystallization from Aqueous Solution
 Water of crystallization are water molecules that are present inside the crystals.
 Water is often incorporated in the formation of crystals from aqueous solution.
 Water of crystallization is the total mass of water in a substance at a given temperature.
 Water of crystallization refers to water that is found in the crystalline framework of metal complex or a salt,
which is not directly bonded to the metal cation.
 Crystallization from Aqueous Solvent 12 of metal complex or a salt, which is not directly bonded to the metal
cation.
 Upon crystallization from water or moist solvents, many compounds incorporate water molecule in their
crystalline frameworks.
 Water of crystallization can generally be removed by heating a sample but the crystalline properties are often lost.
 Ex. In case of sodium chloride, the dehydrate unstable at room temperature compared to inorganic salt protein
crystallize with amount of water in the crystal lattice.

13. Crystallization from Non-Aqueous Solution
 Crystal growth in non aqueous solutions often allows realization of special crystallization aims by control of the
solution properties.
 Solvents are classified to further understand solubility of electrolytes and non electrolytes.
 Several solvents and solubility effects are then pointed out such as the effect on the nucleation, which is easier when
solubility is higher in the crystallization of polymorph and on the surface morphology of the crystals.
 Solvent also change growth rate altering properties of the adsorption layer.
 In non electrolyte solution, the molecules of the solute are not dissociated during that dissolution process.
 Solvent and Solubility:
With the use of non aqueous solvent it is sometime possible to fit the solute-solvent system to some aims such as
modification of habit and morphology or even simple use of high low solute concentration.

15. Presence of another substance in mother liquor :
Sodium chloride crystallized from aqueous solutions produces cubic crystals.
If sodium chloride is crystallized from a solution containing a small amount of urea, the crystal
contain will have octahedral faces.
Solvent Consideration :
Hydrogen bonding can influence crystallization.
Presence of benzene can help crystal growth.
Avoid highly volatile solvents.
Avoid long chain alkyl solvents can significantly disordered in crystal.
Choose solvents with ‘ Rigid geometric’

16. Crystal Growth :
Crystal grow by the ordered deposition of the solute molecules onto the surface of
a pre-existing crystals.
Crystal growth is facilitated by the environment changing slowly over time.
Keep Cystal growth away from sources of mechanical agitation (e.g. Vibrations).
Set up away from vacuum pumps, doors, drawers, and so on. Leaves samples for 1
week, “ Don’t check it” with it in case protein.

18. Thank you