Exam 2 Flashcards
What are excipients?
The key ingredient(s) for Controlling Drug Delivery
What are some examples of excipients and what they do?
Coatings can be applied to control diffusion rates
and modify the release properties of the drug from
the interior. Disintegrants can be used to control regions of release based on physicochemical properties * Lubricants can slow dissolution based on properties * Internal excipients can be used to modify the release rates as well Swellable matrices - Non-swelling matrices - inert plastics.
What is important to know about coatings?
Coatings are applied to the outside of solid dosage forms
to accomplish the following:
-protection of agent from air and/or humidity
-mask taste
-provide special drug release
-aesthetics
-prevent inadvertent contact with drug
What should you know about enteric coatings?
The primary reasons for Enteric Coating:
1. To prevent acid sensitive APIs from gastric fluids
2. To prevent gastric distress from the API
3. To target API delivery to a site in the intestine
4. To provide a delayed/sustained release.
5. To deliver the API in a higher local concentration in
the intestines where it may be absorbed and have a higher bioavailability.
What is sustained release?
The onset of pharmacologic action is delayed, but its therapeutic effect has a sustained duration.
What is controlled release?
Goes beyond sustained release. Therefore the kinetics from one dosage unit is reproducible and predictable from one unit to another. Allows us to maintain a narrow drug plasma concentration-Steady State.
What are some examples of traditional controlled released release formulations?
Coated beads, granules, microspheres, multi tablet system, microencapsulated,
What is steady state?
At steady state, the rate going into the body must equal the disposition (the rate distributing early and being metabolized, and/or being excreted from the body throughout
What characteristics make for a oral controlled release formulation?
-Exhibit neither slow or fast rates of absorption
and excretion
-Uniformly absorbed from the gastrointestinal
tract
-Administered in relatively small doses
-Have good safety/therapeutic window * Chronic therapies better suited than acute
What are physiological factors that affecting absorption?
- Absorbing Surface Area
- Residence Time at Absorption Site
- pH changes in lumen
- Permeability/(Perfusion)
– Functional and molecular characteristics of transporters and metabolism - Dietary Fluctuations/Effects
- Complexation/protein binding
- Biliary uptake and clearance
What is important to know about epithelia?
Predominantly used for external surfaces although endothelial cells are epithelioid.
There are several types, simple squamous, simple columnar, translational and stratified squamous.
What is the composition of biological membranes?
All living cells are enclosed by one or more membranes.
The cell membrane is semi-permeable allowing some chemicals to pass through and holding back others.
