Oral Drug Delivery Flashcards
What are advantages to an oral delivery route?(7)
- Patient acceptability and compliance 2. Large surface area for absorption in GI tract 3. Rich blood supply
- Prolonged retention 5. Possible for zero-order controlled release 6. Inexpensive 7. For local or systemic delivery
What is something to be noted about patient compliance?
Many drugs taste bad and it is difficult for people to be perfectly compliant patients.
Why do we want drugs to be near a zero order controlled release?
Body releases substances at very consistent levels and we should try to emulate this with drugs
Why do some drugs cause adverse reactions to an organ that they have nothing to do with?
Body does not like when given a high dose of anything, and may make a person feel sick, headache, vomiting.
What are three factors effecting systemic absorption and bioavailability of a drug? (3)
- Physicochemical properties of the drug
- Formulation factors
- Anatomy and physiology of the drug absorption site
What are some examples of Physicochemical properties effecting systemic absorption and bioavailability of a drug? (3)
Which of these is the biggest problem for drug delivery?
- Drug pKa
- log P
- solubility
- solubility
What are some examples of formulation factors effecting systemic absorption and bioavailability of a drug? (4)
- Type of formulation
- particle size
- surface area
- excipients
What are some examples of anatomy and physiology of the drug absorption site factors effecting systemic absorption and bioavailability of a drug?
(7)
- Transport routes & mechanisms
- GI motility
- pH
- Metabolism
- P-gp efflux
- Presence of food
- Individual variations
-acid in a an acid is
Unionized (less of it in solution)
-acid in a a base is
Ionized (more of it in solution)
-base in a base is
Unionized (more of it in solution
-base in an acid is
Ionized (more of it in solution)
What are ideal log P ranges?
Do most drugs follow these?
1-3
No
What are some dosage forms used for drugs?
7
- Solutions
- Emulsions
- Suspensions
- Powders
- Tablets
- Capsules
- Modified release granules, tablets & capsules (aka controlled, sustained, extended release)
What are dis-advantages to an oral delivery route?(4)
- Variability in patient population
- Adverse reactions
- Proteins & peptides cannot be delivered
- Metabolism & efflux issues
Why does particle size matter?
-Smaller particles of the same amount have much greater surface area. Smaller particles allow for greater dissolution
What is formulation are drugs in to give greatest surface area?
Micronized or microcrystalline drug forms
What are 5 examples of excipients?
- Wetting agents/ surfactants
- Diluents
- Binders (adhesives)
- Disintegrants
- Lubricants
What is an excipient?
An excipient is a natural or synthetic substance formulated alongside the active ingredient of a medication
What are wetting agents/ surfactants?An example? (2)What do they do?
-Surfactants are compounds that lower the surface tension between two liquids or between a liquid and a solid. Also help with absorption of drugs.-Polysorbate 80 and Sodium dodecyl sulfate
What is a diluent?What are they for?
-Something used to bulk up drugs for oral consumption-Allow for a person to pick up a drug.-
What are some examples of diluents? (3)
Lactose, dextrose, sucrose, microcrystalline cellulose
Hydrophilic diluents cause …
rapid tablet disintegration (want the tablet to go all at once)
Hydrophobic diluents …
decrease dissolution rate of drug (extended release)
What is a binder?
Something that you organize your papers with. lulz jkHelp bind powders during the granulation processes & help with compression
What are examples of binders?(3)
What is a particularly good binder?
- Starch mucilage
- gelatin
- polyvinylpyrrolidone
- Starch mucilage
How can binders control drug release rate?
-For a slower release coating drug particles with starch (which is a slowly dissolving binder)-For faster release coating drug particles with gelatin or PVP (which are soluble binders)
What is something to note about particles that are used in binding?
When you look at them they have very jagged edges.
What are Disintegrants?What are they for?
-Swell in presence of water to burst open tablet-They are for rapid dissolution and higher bioavailability
What are lubricants?What are they used for?What are two key properties they should have?
-substance introduced to reduce friction between surfaces in mutual contact-help tablet ejection from machines and; improve flow-Tend to be hydrophobic and; retard dissolution
What are some examples of lubricants used in pharmacy?
Stearic acid its Mg and Ca salts widely used
What is the pH of saliva?
What is transit time approximately?
pH: 6.5-7.5
Transit time: less than 1 minutes
What is the pH of the stomach?
What is transit time approximately?
pH: 1-3.5
Transit time for liquids: 8-12 minutes
Transit time for solids: 144-277 minutes
What is the pH of the duodenum?
What is transit time approximately?
pH: 5-7
Transit time for liquids: 2-60 minutes
Transit time for solids: 2-60 minutes
What is the pH of the jejunum and Ileum?
What is transit time approximately?
pH: 6-7.5
Transit time for liquids: 1-3 hours
Transit time for solids: 1-5 hours
What is the pH of the Colon?
What is transit time approximately?
pH: 5.5-7
Transit time: 12-48 hours
What is the pH of the Rectum?
pH: 7
What is something that the FDA requires on all tablets?
That they are able to disenergrate
What happens to stomach pH as more food is consumed?
The pH increases (Volume of liquid expands)
Liquids vs. solids which one gets processed faster by the GI tract?
Liquids
What is the colons main job?
to reabsorb water
Where are really hot or really cold foods kept until they reach a normal temperature?
The stomach
What is pH in the GI tract most affected by?
Diet
