Lecture 18- Kinetics Of Degradation 1 Flashcards
Drug stability
Ability of a pharmaceutical dosage form to maintain the physical, chemical, therapeutic and microbial properties during the time of storage and usage by the patient
Drug stability; shelf life
Time during which the medicinal product is predicted to remain fit for its intended use under specified conditions of storage
Time from manufacture/prep until the original potency/content of the active ingredient has been reduced by 10%- limit of chemical degradation
Types of stability which are of concern to pharmaceutical industry
Chemical- each active ingredient retains its chemical integrity and labelled potency within the specified limits
Physical- original physical properties; including appearance, palatability, mp, clarity + colour of solution, moisture, particle size etc are retained
Microbiological- sterility/ resistance to microbial growth is retained according to specified requirements.
Therapeutic- effects remain unchanged
Toxicological- no significant increase in toxicity occurs
Purpose of stability testing in the context of drug substances and formulations
Provides evidence on how the quality of a drug substance or drug product varies with time under the influence of environmental factors such as; temp, humidity, oxidation, light + microbial exposure
- used to establish the shelf life for a drug product
Stress testing and its role in the development of pharmaceutical formulations
Process that involves degradation of drug products + drug substances under conditions exceeding those used for accelerated testing + generates degredation products that can be studied to determine the stability of the molecule
Stress testing + what is pt is its role continued
-Establish degredation pathways of drug substances and drug products
-Differentiate degradation products that are related to drug substances from those that are generated from non-drug substances in a formulation
-Elucidate the structure of degradation products
-Determine the intrinsic stability of a drug substance in a formulation
- Understand chemical properties of drug molecules
Long term + Accelerated stability studies
Long term;
Study is performed at 25 degrees; 60 RH/ 30 degrees; 65 RH
Parenterals= stability has to be carried out 2-8 degrees
Drugs stored in the freezer= testing should be done at -20 degrees
Accelerated;
Storage conditions of 40 degrees; 75 RH (relative humidity)
Studies carried out 6 months
Rates and orders of reactions
Rates;
Speed or velocity of a reaction with which a reactant or reactants undergo a change
Determined by the change in concentration of the reactants/products as a function of time
Rate, velocity or speed of a reaction given by the expression;
dc/dt= Rate= kc
Dc is increase/decrease of conc over a time interval
