Kinetics of degradation 1

Question 1

what is drug stability

Answer 1

the ability of a drug to maintain physical, chemical, toxicological, microbial and therapeutic properties during the time of storage and usage by patient

Question 2

Types of stability which are of concern to Pharmaceutical Industry DESCRIBE/EXPLAIN

Answer 2

Chemical
Each active ingredient retains its chemical integrity and labelled potency within the specified limits.

Physical
The original physical properties, including appearance, palatability, melting point, clarity and colour of solution, moisture, particle size, uniformity, dissolution & suspendability are retained.

Microbiological
Sterility or resistance to microbial growth is retained according to the specified requirements. Antimicrobial agents retain effectiveness within specified limits.

Therapeutic
The therapeutic effects remain unchanged.

Toxicological
No significant increase in toxicity occurs.

Question 3

what is shelf life?

Answer 3

The time during which the medicinal product is predicted to remain fit for intended use under specified conditions of storage.

Time from manufacture / preparation until original potency or content of active ingredient has been reduced by 10% [t10 or t90] which is the limit of chemical degradation

Question 4

Stability testing important in

Answer 4

Provide evidence on how the quality of a drug substance or drug product varies with time under the influence of a variety of environmental factors.

temperature, humidity, oxidation, light and microbial exposure

Stability testing is also used to establish the shelf life of a drug product and the recommended storage conditions.

Question 5

What is stress testing

Answer 5

Is a process that involves degradation of drug products and drug substances under conditions exceeding those used for accelerated testing and thus generates degradation products that can be studied to determine the stability of the molecule.

Question 6

Long term stability studies

Answer 6

25ºC/60% RH or 30ºC/65% RH – 12 months (or minimum of 6) (parenteral 2-8ºC, freezer -20ºC)

Question 7

Intermediate studies

Answer 7

30ºC ± 2C / 65% ± 5% RH – 6 months

Question 8

Accelerated testing

Answer 8

40°C and relative humidity of 75% RH for drug substances and drug products

Question 9

Rates and orders of reaction

Answer 9

The speed or velocity of a reaction with which a reactant or reactants undergoes a change.
Determined by the change in the concentration of the reactants or products as a function of time.

Question 10

The rate, velocity or speed of a reaction is given by the expression

Answer 10

dc/dt = Rate = kc
Where dc is increase or decrease of concentration over a time interval dt.

Question 11

Stress testing and its role in the development of pharmaceutical formulations

Answer 11

1. To establish degradation pathways of drug substances and drug products
2. To elucidate the structure of degradation products
3. To establish stability indicating nature of a developed method
4. To understand the chemical properties of drug molecules
5. To generate more stable formulations
6. To solve stability-related problems