RE lecture 2 Flashcards
What is Caco-2 and what is it used for?
- Cacpo-2 is an immortalized cell line of human colorectal adenocarcinoma cells.
- It is used to measure a drug’s permeability, where the cells are used as a model of the intestinal epithelial barrier
What are the advantages of liquid dosage forms?
- easier to swallow
- pleasant appearance which is acceptable
- Dosing is more flexible because you can adjust volume
- More rapidly absorbed than tablets/capsules
- Bitter drugs can be given flvoured
What are the disadvantages of liquid dosage forms?
- shorter shelf life
- Needs preservatives
- Bulky for transport and storage, may require special storage conditions (eg for vaccines)
- Less convenient dosing
- Dose accuracy depends on patient’s measurement
Why is bad for protein based drugs to have a pH equal to their isoelectric point?
- when pH=isoelectric point, the protein has net 0 charge
- The protein molecules cannot repel each other, so they start to aggregate and precipitate out of solution
Why are some drugs formulated as suspensions?
- They are not soluble in water
- Drugs with bad taste are made into insoluble derivatives
- Prolong the release of the drug for intramuscular and subcutaneous injections
- For people with difficulty swallowing tablets
In a suspension, why are the suspending agents usually made of long chain polymers?
They are viscous, so it makes the suspension particles settle more slowly and prevents agglomeration.
What is an emulsion?
A mixture of oil and aqueous phases stabilized by surfactants or emulsifying agents.
Why are some drugs formulated as emulsions?
- They are poorly soluble in water but readily soluble in oils
- It masks the bitter taste and odour of drugs
- The drug is more stable in the oily phase than the aqueous
- Prolong the release of the drug for sustained release
- Nutrients can be emulsified and given as IV injections
- They provide protection to drugs which are susceptible to oxidation or hydrolysis
What dosage forms can be injected?
- Solutions
- Emulsions
- Suspensions (NOT IV)
When the ratio of the area under the curve of a drug in suspension over solution is _________, they proceed with conventional formulation.
50% or more
Is it possible to inject lipophilic substances directly into the bloodstream via IV?
no
How are lipophilic substances injected via IV?
Through an O/W emulsion.
Why do single use vials not have preservatives?
They want to avoid using more excipients
Can suspensions be injected through IV, IM and SC?
- Yes for IM and SC
- No for IV
Why can’t suspensions be injected through IV?
- They may clog up arteries
- The immune system might recognise and attack it
Can the API from a cream enter the bloodstream?
Yes
What is the difference between a cream and an ointment?
- Creams contain less oil than ointments
- Ointments usually contain petrolatum
Are gels water soluble?
Yes
What are the advantages of capsules?
- Unpleasant taste is readily masked
- Easy to swallow
- Fewer excipients required than tablets
- Rapid and uniform release of medication
- Can protect light sensitive agents (opaque capsule)
Which capsule (hard or soft) can protect the drug from oxidation?
soft
Which capsule (hard or soft) is used for liquid medication?
Soft
What are the advantages of suppositories?
- Fast acting
- Good for unconscious patients
- Good for patients who can’t swallow or have nausea
What are the disadvantages of suppositories?
- Inconvenient
- Small dosage
- Variable absorption
- Potential for leakage
What is the purpose of enabling formulations?
To make drug candidates with poor dissolution characteristics more bioavailable
