Flashcards in Stability of drugs Deck (18):
Lactams are more susceptible to hydrolysis than esters. True or false?
Imides are less susceptible to hydrolysis than amides. True or false?
Which are most susceptible to hydrolysis, esters or amides?
Hydrolysis is a zero order reaction. True or false?
False - first order
Hydrolysis is pH dependent - so the lower the logK, the higher the rate of hydrolysis and so the more the drug will degrade. True or false?
False - the higher the logK the more the drug will degrade
Oxidation is promoted in the presence of oxygen. What else promotes oxidation?
presence of oxidising agents
Highly conjugated metals are susceptible to photodegradation. True or false?
Energy increases as wavelength increases. True or false?
False - energy increases with decreasing wavelength
What is light induced degradation called?
Isomeric change may affect pharmacological and toxicological activity. True or false?
The L form of adrenaline is more active than the D form. True or false?
Optical rotation is used to detect isomeric change because there is no change in mass so mass spec etc. is not useful. True or false?
The chemical stability of proteins and peptides is dependent on amino acid composition and sequence. True or false?
How do inert gases stabilise pharmaceutical preparations?
They protect from auto-oxidation
Why is procaine more prone to hydrolysis than lidocaine?
Procaine is an ester so more prone to hydrolysis than lidocaine, an amide
What is the equation for half life of a first order reaction?
T1/2 = In(2)/k
What is the equation for shelf life of a first order reaction?
T90 = In(1.11)/k