Drug Stability

Question 1

What is the definition of drug stability

Answer 1

-The capacity of particular drug formulation in a specific container
-to remain within a particular
-chemical,microbiological,therapeutic,physical and toxicological specification
-in a specified period of time

Question 2

Drug instability definition

Answer 2

-The incapability for the pharmaceutical dosage form
-to maintain the physical,chemical, therapeutic and microbiological properties
-during the time of storage and usage by the patients

Question 3

Shelf life definition

Answer 3

The time required to degrade a pharmaceutical dosage form to 10% which pharmaceutically acceptable.

Question 4

Definition of expiry date

Answer 4

The point of time when the pharmaceutical dosage form is no longer within an acceptable condition to be considered effective for the patient and the medication reaches the end of its useable ‘shelf life’

Question 5

Factors that affecting drug stability

Answer 5

-pH
-Temp.
-moisture
-humidity
-light
-storage and closures and containers
-oxygen
-particles size
-additives
-molecular binding
-diffusion of drugs and excipients

Question 6

Meaning of hydrolysis

Answer 6

A chemical reaction that occurs when a molecule reacts with water resulting a cleavage of chemical bond within that molecule.

Question 7

Preventive measures from hydrolysis

Answer 7

-adjustment of pH
~low pH, increase the drug stability
~rate decomposition depends on the pH
-choices of solvent
-addition of the surfactant
~improve stability due to the micelles formation
-production of the insoluble form of drug
~making suspension
~prepare insoluble salt of drug
-modify the chemical structure of the drug
-presence of complexing agent

Question 8

Characteristics of autooxidation

Answer 8

-occurs spontaneously
-in the presence of air or oxygen without direct involvement of an external oxidizing agent
- involve reactive oxygen species

Question 9

Photooxidation

Answer 9

-chemical process that undergo oxidation reaction under the influence of light
-involves the absorption of photons by molecules

Question 10

Isomerization

Answer 10

-the process by which one molecule is transformed into another molecule which has exactly the same atoms but the atoms are rearranged

Question 11

Cis-trans isomerization

Answer 11

= the conversion of cis isomer to trans isomer or vice versa.
-with the involvement of the breaking and reforming double bond.

Question 12

Tautomerization

Answer 12

= involve the conversion of tautomer that differ in the position of protons and double bonds to another.
- involve the transfer of proton from one atom to another

Question 13

Epimerization

Answer 13

=the conversion of one epimer to another which differ configuration at the chiral center.
-involve in breaking and reforming of the covalent bond

Question 14

Conrotatory ring opening

Answer 14

-involve the opening of a cyclic compound to form linear compound
-involving breaking and reforming of pi bonds.

Question 15

E/Z isomerization

Answer 15

-involve the conversion of a molecule from E/Z isomer to another that differ in configuration around double bond.
-involve the rotation of groups around double bond.

Question 16

Polymerisation

Answer 16

=the process by which two or more drug molecules are combine together to form complex molecule
-prevented by adding 10-15% of methanol to the solution.