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55 Cards in this Set
- Front
- Back
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WHAT ARE THE THERAPEUTIC BENEFITS OF NOVEL DRUG DELIVERY SYSTEM
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OPTIMIZATION of duration of drug action
DECREASE in drug dosing frequency CONTROLLING site of drug release MAINTANENCE of constant drug levels |
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what are the economic benefits of novel drug deliv system
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SIMPLIFICATION of drug administrative regimens
ENHANCING patient compliance overall REDUCTION in health cost |
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what is the magic bullet concept about
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if a compound could selectively target a disease causing organism, then a toxin for that organism could be delivered along with the agent of selectivity
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what is the rationale behind dosage form design and controlled drug delivery systems
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to promote therapeutic benefits while minimizing toxic effects
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what can controlled/sustained drug delivery do
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reduce the UNDESIRABLE fluctuation of drug levels, enhancing THERAPEUTIC action and ELIMINATING dangerous side effects
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what are the three ways drugs can be delivered w/ prodrugs
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either the prodrug gets cleaved and the drug becomes active
the prodrug-drug complex undergoes a conformational change and becomes active the targeting moiety and carrier get cleaved off the active drug |
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what are the components of a targeted drug delivery system
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drug
targeting moiety carrier |
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what are the functions of targeted systems
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prevent degradation of the active components
reduce total body clearance maintain drug activity during transport to site of action release the drug at the target site from the delivery system |
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what are all the prodrugs
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Sparingly souluble salts
Acyloxymethyl derivatives Dextran derivatives Peptide modification (PEG) Other enzymatic cleavage mechanisms Esters |
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what are liposomes used for
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carry the druge to a site of action or to promote controlled release in the body
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what are some of the benefits of liposome drug delivery
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reduced toxicity and enhanced targeting
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what happens when Doxorubicin HCl is packaged in PEG stabalized liposomes or a nomal liposome
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w/ PEG it is used to treat AIDS related KS disease
w/ a normal liposome it is used to treat metastatic ovarian carinoma |
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liposomes with PEG on their surface are what and what can they do
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these liposomes are known as stealth liposomes and will be undetectable/invicible to the bodies immune system and can circulate the body w/o being taken up by macrophages
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what can targeted liposomes do
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the can attach to a specific antibody at parts of body
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what can cationic liposomes do
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molecules on surface can combine w/ gene delivery system (DNA/RNA) or short peptides
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what is a monolithic device
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a rate controlling polymer matrix throughout which the drug is dissolved or dispersed
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what is a reservoir device
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it consists of a shell like dosage form with the drug or agent contained within the rate controlling membrane
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what are laminated reservoir device
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they are designed for attachment to skin, mouth lining, or cornea of eye. (they have an adhesive backing)
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what are microparticles
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consist of a solid matrix throughout which drug is distributed
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what are nano particles
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consist of a solid matrix with minute particles (10nm to 2um). minimize drug toxicity and have tendency to accumulate in areas of inflammation in the body (useful for targeting those areas)
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what are microcapsules
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solids/liquids/gases are enveloped in a membrane which is semipermeable or impermeable but dissolves under certain conditions like pH changes. compressions of microcapsules into tablets can result in sustained action.
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what are nanocapsules
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drug in oily solution or suspension enclosed in a shell. it is used to minimize toxicity and have a tendency to accumulate in areas of inflammation in the body.
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what kind of microcapsules and nanocapsules can you have
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fused or agglomerated
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what are the biodegradable polymers in laminated reservoir device
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poly(lactic acid)
poly(glycolic acid) gluatamic acid-ethyl glutamate copolymers polyacrylamides |
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what route of drug delivery goes through first pass
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only oral
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what are the two main barriers to occular drug delivery
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cornea in the front of the eye
blood retina barrier in the back of the eye |
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what are the traditional occular drug delivery approaches
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eye drops
system injection |
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what are the drug delivery approaches to eye drops
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limited penetration in the front of the eye
no penetration in the back of the eye tear washout rapidly diluted poor patient compliance |
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what are the drug delivery approaches to injections
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traumatic
rapidly diluted circulatory process quickly reduces bioavailability repeat procedures |
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what are the drug delivery approaches to systemic
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limited penetration
high drug levels are toxic |
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what are the occular administration to optimize occular drug delivery
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good corneal penetration (ether/sulfoxides)
prolonged contact time w/ corneal epithelium simplicity of installation for patient nonirrative and comfortable form appropriate rheologic properties |
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how can prolonged drug action be achieved w/ ocular drug delivery
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reducing drainage of drug by using viscosity enhancing agents, suspensions, emulsions, erodible and nonerobile matrices
enhancing corneal penetration by using prodrugs and liposomes controlled devices |
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what is Fick's law
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M = SDKCst/h
M = accumulated amount released S = surface area D = diffusion coefficient K = partition coefficient Cs = solubility of drug in water t = time h = thickness of membrane |
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where is Surodex BDD instered and for how long
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in the fron of the eye for 7 days
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where is Posurodex BDD insterted and for how long
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in the back of the eye for 2-3 months
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why are systemic administration also possible nasal
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due to its high vascularity
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why can potent drugs be given nasally
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due to the small surface area of the nose only have to give a small dosing amount
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how does nasal administration bypass first pass
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drug absorbtion through the sinuses goes immediately into systemic circulation
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how large must particles be in order to remain in the nose
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greater than 4um
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what MW give good bioavalability
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a MW of 1000 daltons yields good bioavailability but a MW of 6000 daltons will require enhancers to improve bioavailability
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what is done to facilitate nasal absorption
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strutural modification of drug
salt or ester formation of the drug for better membrane permeability formulation design (proper excipients can improve drug stability or enhance absorption) surfactants can modify the permeability of nasal mucosa by lowering surface tension |
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what is the onset of action in pulmonary administration similar to
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IV
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what are the major challenges of pulmonary administration
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lack of reproducibility in the deposition site
rate of absorption of the drug varies due to thickness of the epithelial lining in the bronchial tree |
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what are widely used to deliver drugs to the respiratory track
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aerosols
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what does the deposition mechanism of particles depend on in pulmonary administration
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inhalation regime
particle size, shape, density |
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what particle size is filtered by the nose or cleared from the nasal and oral pharynx by coughing or sneezing
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10um
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what particle size gets trapped in mucous blanket of the airways
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5-10um
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what particle size can penetrate into bronchial and alveolar regions
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<2um
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what is the equation for sedimentation efficiency
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S = distance the particle falls during breath holding/mean regional airway diameter
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what is the mean regional airway diameter for the mouth, tracheobronchail region, and alveolar region
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5cm for mouth
.2 cm for trancheobronchial region .073 for alveolar region |
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when S >1 what is S
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1
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what is the equation for exhaled dose fraction
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E = 1 - (Fm + Ftb + Fp)
Fm = fractional deposition in mouth Ftb = fractional deposition in tracheobronchail region Fp = fractional deposition in alveolary region |
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what is the sedimentation dose fraction
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SDF = E x SVr/Vt
E = exhaled dose fraction S = sedimentation efficiency Vr = regional volume of M, TB, P Vt = total lung volume after inhalation |
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what is the regional volume of the mouth, tracheobronchial region, and alveolar region
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30, 170, 2800cm3
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what does the duration of local therapeutic activity in the lung depend on
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particle deposition
mucociliary clearance drug dissolution or release (for solid particles) absorption tissue sequestration |
