dosage forms 5 Flash Cards

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Title:	dosage forms 5
Description:	mobely pg 7 and on
Number of Cards:	70
Save Count:	1
Author:	wlm05c7
Created:	2008-12-16
Tags:	2 amadre dosage forms uf
Private	No

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- Question
- Answer
- Side 3

- t/f
  The major pathways for a topical ophthalmic to reach intraocular tissues are through the cornea and sclera
- true
- t/f
  The major pathways for a topical ophthalmic to reach intraocular tissues are through the cornea and sclera
  passage through the sclera dominates
- false,
  passage through the cornea dominates
- what are the names of the three layers that make up the tear film?
- (1) Mucoid layer
  o Involved in adhesion of the aqueous tear fluid.
  o Keeps the cornea wettable
  (2) Tear fluid
  o Aqueous solution of inorganic electrolytes, proteins and glucose
  o Proteins in tears: enzymes and immunoglobulins
  
  (3) Lipid film
  o A layer of wax and cholesterol esters adsorbed to the tear fluid.
  o Lipid film: reduces evaporation of the tear fluid
- t/f
  the *tear fluid* is involved in adhesion of the aqueous tear fluid. Keeps the cornea wettable
- false-Mucoid layer
  
  the Tear fluid
  -Aqueous solution of inorganic electrolytes, proteins and glucose
  Proteins in tears: enzymes and immunoglobulins
- t/f
  Lipid film is a layer of wax and cholesterol esters adsorbed to the tear fluid.
  Lipid film: reduces evaporation of the tear fluid
- true
- what layer of the tear film keeps the cornea wettable?
  
  a-mucoid layer
  b-tear fluid
  c-lipid film
- mucoid layer-
  it also is involved in adhesion of the aqueous tear fluid
- what layer of the tear film reduces evaporation of the tear fluid?
  
  a-mucoid layer
  b-tear fluid
  c-lipid film
- lipid film
  it also is a layer of wax and cholesterol esters absorbed to the tear fluid
- what layer of the tear flim has enzymes and immunoglobulins?
  
  a-mucoid layer
  b-tear fluid
  c-lipid film
- tear fluid
  also has aqueous solution of inorganic electrolytes, proteins and glucose
- what factor of a drug provides the driving force for passive diffusion through the cornea?
- concentration of the drug
  
  passive diffusion dominates corneal permeation
- Put the layers of the cornea in order from outer to inner:
  
  stroma
  endothelium
  epithelium
- outer-epithelium
  middle-stroma
  inner-endothelium
- what layer(s) of the cornea are lipophilic?
  what layer(s) of the cornea are hydrophilic?
  
  a-Epithelium
  b-stroma
  c-endothelium
- epithelium and endothelium are lipophilic
  
  the stroma is hydrophilic
- what layer of the cornea is continuous with the conjuctiva but with a different thickness?
  
  a-Epithelium
  b-stroma
  c-endothelium
- corneal epithelium
- what layer of the cornea is about 60 thin lamella, each composed of collagen fibers.
  
  a-Epithelium
  b-stroma
  c-endothelium
- stroma
- what layer of the cornea is the main barrier for drug passage through the cornea?
  
  a-Epithelium
  b-stroma
  c-endothelium
- epithelium
- what layer of the cornea is mostly water?
  
  a-Epithelium
  b-stroma
  c-endothelium
- stroma
- what layer of the cornea is made up of stratified epithelium?
  
  a-Epithelium
  b-stroma
  c-endothelium
- epithelium
- what layer of the cornea contains enzymes such as esterase , peptidases, and proteases?
  
  a-Epithelium
  b-stroma
  c-endothelium
- epithelium
- what layer of the cornea consists of a single cell layer that provides metabolic exchange between the cornea and the aqueous humor
  
  a-Epithelium
  b-stroma
  c-endothelium
- endothelium
  
  up to 200 times more permeable than the epithelium
- what layer of the cornea consists of squamous cells on the surface and these cells are surrounded by tight junctions and have microvilli?
  
  a-Epithelium
  b-stroma
  c-endothelium
- epithelium
- t/f
  drugs with a moderate ethanol/water partition at physiological pH are best absorbed
- false,
  drugs with a moderate octanol/water partition at physiological pH are best absorbed - because of the diverse barriers
- t/f
  the epithelium of the cornea is made of a single cell layer that provides metabolic exchange between the cornea and the aqueous humor
- false
  the endothelium is made of asingle cell layer that provides metabolic exchange between the cornea and the aqueous humor
- t/f
  less effective absorption occurs through damaged epithelium
- false
  greater absorption occurs through damaged epithelium
- the time to peak aqueous humor concentrations often range between ___and ___minutes
- 20-60 minutes
- normally, less than ___% of the dose (instilled as drops) will traverse the cornea
- 5%
- applied drug can be removed from the surface of the eye by spillage and by the _____ drainage
- nasolacrimal drainage
- what is the range of an eyedrop? (volume)
  
  tear?
- eyedrop= 25 to 56 microliters
  
  normal tear volume=7 microliters
- t/f
  a possible source of drug loss before crossing the cornea is that less than 30% of the dose(instilled in drops) will traverse the cornea
- false 5% of the dose will traverse cornea
- how much volume can be accommodated in the lower cul-de-sac without spillage?
  
  A-5 microliters
  b-20 microliters
  c-30 microliters
  d-60 microliters
  e-100 microlites
  f-1 microliters
- 30 microliters
- ____ forces fluid to the nasal cavity
- blink pumping
  
  gravity and blink pumping mechanism forces fluid through the puncta to the nasolacrimal apparatus
- what is the most common drug binding protein?
  
  a-dextrose
  b-lacarin
  c-benzalkonium chloride (BAC)
  d-mannatol
  e-Melanin
  f-glycerin
- melanin
  -some drugs can bind to melinin in the iris
- t/f
  when treating the posterior region of the eye, a topical product is usually used
- false,
  treating posterior region problems are typically not achievable with a topical product
- t/f
  drugs can not enter the systemic circulation from the eye
- false, drugs can enter the systemic circulation from the eye
- t/f
  the cornea is more permeable than the conjuctiva and covers a much greater surface area
- false
  
  the conjuctiva is more permeable than the cornea and covers a much greater surface area
- t/f
  the conjuctiva is highly vascularized
- true
- t/f
  there is no hepatic first pass with absorption from within the eye
- true
- over ___% of the instilled dose can be systemically absorbed and you can get systemic effects
- 50%
- what is the organism that can cause problems in ophthalmics?
  
  A- S. bacilli
  b- S. pneumonia
  c- P. Streptococcus
  D- Corynebacterium
  E- P. aeruginosa
- pseudomonas aeruginosa
- t/f
  Pseudomonas aeruginosa can cause blindness
- true
- ___ is used as a antimicrobial preservative to fight off pseudomonas aeruginosa. It can damage corneal epithelium if too concentrated.
  
  a- Polyquad (polyquaterium-1)
  b- thimerosal
  c-benzalkonium chloride (BAC)
  d-oxidants
- benzalkonium chloride
- what antimicrobial preservative is the alternative to BAC that doesn't penetrate the cornea well, and is almost nonsensitizing?
  
  a- Polyquad (polyquaterium-1)
  b- thimerosal
  c-benzalkonium chloride (BAC)
  d-oxidants
  e-antioxidants
- polyquad
- what antimicrobial preservative is a organic mercurial and hypersensitivity is a problem?
  
  a- Polyquad (polyquaterium-1)
  b- thimerosal
  c-benzalkonium chloride (BAC)
  d-oxidants
  e-antioxdants
- thimerosal
- what do we use to kill bacteria naturally?
  
  a- Polyquad (polyquaterium-1)
  b- thimerosal
  c-benzalkonium chloride (BAC)
  d-oxidants
  e-antioxidants
- oxidants
- what is the normal pH ot tears?
- 7-7.4
- which are strong acids used to buffer pH levels in the eye?
  
  strong Base?
  A-HCl
  b-NaOH
  c-H2SO4
  d-PO4
  E-HSO4
- Strong acid-HCl or H2SO4
  
  Strong base- NaOH
- what is the normal osmolarity of tears? mOsm/kg
  
  a- 302-318
  b-318-332
  c- 402-418
  d-418-432
- 302-318 mOsm/kg
- what are the 3 most common tonicity modifiers?
  
  A-NaCl
  B-SO4
  C-Mannitol
  D-glycerin
  E-cellulose derivatives
  f-dextrose
  g-Polyvinyl alcohol
  h-PEGs
- NaCl, Mannitol, dextrose(isotonic)
- Increase viscosity of eye fluid (increases or decreases) bioavailability
  
  what does viscosity do to retention time and drainage rate?
- increase retention time/reduce drainage rate so it:
  
  increase bioavailability
- what are some examples of viscosity modifiers used in artificial tear products?
  
  A-NaCl
  B-SO4
  C-Mannitol
  D-glycerin
  E-cellulose derivatives
  f-dextrose
  g-Polyvinyl alcohol
  h-PEGs
- Glycerin, cellulose derivatives (hydroxyethylcellulose), polyvinyl alcohol, PEGs
- what are HCl, H2SO4, and NaOH used to modify?
  A-pH
  B-Osmolarity (tonicity)
  C-Viscosity
  d-sterility
- buffer pH:
  H2SO4 and HCl -strong acids
  NaOH- strong base
- what are
  Glycerin, cellulose derivatives (hydroxyethylcellulose), polyvinyl alcohol, PEGs
  used for?
  
  A-pH
  B-Osmolarity (tonicity)
  C-Viscosity
  d-sterility
- viscosity
- what is benzalkonium chloride (BAC), polyquad (polyquaternium 1), thimerosal used for?
  modification of:
  A-pH
  B-Osmolarity (tonicity)
  C-Viscosity
  d-sterility
- sterility
- what does blinking and reflex tearing accomplish?
- speeds up drug elimination from the eye surface. (caused by osmolarity outside the normal range of 302-318 mOsM/KG)
- what are NaCl, Mannitol, dextrose(isotonic)used for?
  
  modifiers of:
  
  A-pH
  B-Osmolarity (tonicity)
  C-Viscosity
  d-sterility
- tonicity modifiers
- what are two methods of sterilizing liquid Ophthalmic) eyedrop solutions?
- heat or membrane filter
- what size are the particles reduced to in an eyedrop (liquid ophthalmic) suspension?
- less than 10 micrometers
- how do you get a eyedrop suspension clean?
- can't filter-sterilize (will remove drug particles), so must aseptically add the sterilized solid to the sterilized solution.
- t/f
  Ophthalmic suspentions are used for poorly lipid soluble drugs or to improve stability
- false
  Ophthalmic suspentions are used for poorly *water-soluble* drugs or to improve stability
- t/f
  ophthalmic suspensions do not provide a drug depot, they mix with tears less rapidly.
- true
  
  (*thus remain in the cul-de-sac longer)
- when you see sulfite, think:
  
  A-suspension
  b-solution
  c-chelator
  d-antioxadant
  e-oxidant
- antioxidant
- what is EDTA?
  
  A-suspension
  b-solution
  c-surfactant
  d-antioxadant
  e-oxidant
  f-chelator
- chelator
- other than it's ability ot limit oxidation by chelating metals, EDTA has another important function, what is it?
- EDTA increases the activity of BAC (benzalkonium chloride) against P. aeruginosa.
- Polysorbate 80 (tween)is an example of :
  
  A-suspension
  b-solution
  c-surfactant
  d-antioxadant
  e-oxidant
  f-chelator
- surfactant
  used as a wetting agent for suspentions and can facilitate spreading of the drops-reduce surface tension
- why are standard volums of eyedrops less than 30ml?
- because you SHOUld not have them for over a month
- what is the main advantage to ophthalmic ointments
- prolonged contact time
  cleared very slowly, as slowly as 0.5% per minute
- what is the main disadvantage to ophthalmic ointments?
- can cause blurred vision and matting of the eyelid
- what is the usual base of ophthalmic ointment?
  
  a-petrolatum
  b-white petrolatum
  c-yellow petrolatum
- white petrolatum
  
  with or without mineral oil, mineral oil reduces viscosity
- how do you sterilize an ophthalmic ointment?
- heat ointment base, then filter while molten.
- when is a ophthalmic ointment most often used?
- following surgery
- what is the least common type of semisolid ophthalmic?
- gel
- what do ophthalmic gels incorporate to make the gel jelly?
- carbomer or gums