Dosage Forms Exam 4 Flashcards
What happens in hydrolysis?
-water often reacts and degrades drugs
-never store medicine in a humid environment
accelerated stability
-accelerated breakdown of a drug in aqueous solution if temperature is increased
-a solution drug will only be stable at a given: concentration, for a certain time, at a certain temperature, at a certain degree of light exposure
-a solid drug will be stable at: all the same except not at a given concentration
Chemical reactions that can cause degradation: hydrolysis, photolysis, Oxidation-reduction
functions of dosage forms
-provide an accurate dose
-promote drug dissolution
-promote delivery to site of action
-ensure drug stability
-control drug delivery to the body
-determine dosing interval
How can hydrolysis of esters and lactones be prevented?
-protect from moisture
-protect from heat
-control pH in solution formulations
How can hydrolysis of amides and lactams be prevented?
-protect from moisture
-protect from heat
-control pH in solution formulations
summary
-oxidation is a common, and complicated, route of drug degradation
-Photolysis is drug degradation caused by exposure to light
-many different functional groups are subject to oxidation
-oxidation can be minimized by protecting from air, light and metals, excipients added to the formulation
What is zero-order kinetics?
rate of drug degradation is constant, independent of concentration
What are some stability issues for biologics?
-more fragile
-more bonds that can break (because they are larger)
-lost activity if they unfold
-can aggregate (increase/decrease potency, increased potential for adverse immune response)
How do protein drugs degrade?
-chemical degradation (breaks covalent bonds/form new ones, Hydrolytic reactions, oxidation reactions)
-Physical degradation (changes protein structure, covalent bonds not broken, unfolding, aggregation)
What are some common routes of protein degradation?
Hydrolytic reactions (asparagine deamination; peptide bond hydrolysis)
Oxidation reactions (methionine oxidation; disulfide bond scrambling)
Aggregation
Solubility and Bioavailability
-depends not only on having the drug in solution, but also on the drug’s permeability
Enteric polymers
-release drug in small intestine
Matrix tablet
-drug embedded in polymer matrix
-release via diffusion or erosion
Describe the elementary osmotic pump
-single or double chamber
-osmotic drug core
-fills up with water and drug goes through delivery orifice
What are types of innovation?
Group A types- involves tweaking already exisiting products
Group B types- based on analogy
Group C types- wild ideas
Innovation pipeline- lots need to go in for something to come out (idea, concept, experiment, Pilot, Launch)
