Term
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Definition
a device which is surgically/manually embedded in the body
transplant is a organ or tissue from 1 person to another |
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Term
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Definition
pumps with prefilled reservoir
coated stent
pure drug
polymeric formulations designed to achieve types of release (diffusion or erosion) |
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Term
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Definition
prolong drug delivery
joints, stents, joint cements, dental
overcoming poor compliance
vet med |
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Term
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Definition
1st order kinetics: (drug elimination is proportional to its conc)
2nd order kinetics: (drug elimination is independent of the drugs conc)
improved complication
less administration
mainly zero order
reduced toxicity
avoid 1st pass effect
avoids handling of cytotoxic meds
early release from hospital |
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Term
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Definition
a device controls the rate of drug release not the conc.
ensures a steady amount of drug release over time, minimising peaks/trough and S/E, while maximising drug conc and desired levels
important for narrow therapeutic index (NTI) |
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Term
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Definition
may dose dump if payload is high and give toxic effect
high daily dose is unsuitable for implants
unpleasant admin
slow onset |
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Term
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Definition
biodegradable: polylactic acid, polyglycolic acid, poly caprolactone
non-biodegradable: silastic, ethylene vinyl acetate |
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Term
| biodegradable matrix (naltrexone) |
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Definition
competitive mu-opioid antagonist
greater affinity for mu receptors than opioid agents and blocks effects
may eliminate use of opioid
triggers a withdrawal syndrome
rapid detoxification before using naltrexone |
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Term
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Definition
release thru diffusion or erosion
no removal required
need to know location (if needs to be removed)
use for less admin and reduced withdrawal relapse between doses |
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Term
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Definition
local anaesthetic
7mm incision
in subcut fat
use sterile syringe with pellets
implant approx. 8mm in diameter and 5mm in thickness
weighs 310mg containing 108mg of naltrexone |
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Term
| therapeutic requirements of naltrexone implant |
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Definition
blood level: >2ng/ml
1.7g implant: 90 days
3.4g implant 188 days
release rate: 0.4% w/w |
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Term
| histological changes at site |
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Definition
biopsies taken 1 to 38 months post
12 months post show inflammation and foreign body reaction
therefore implants are well tolerated
removal from allergic reactions or infection, but small amount
reduced gradually to normal by 25 months |
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Term
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Definition
contains 68mg of etonogestrel in EVA (copolymer core enclosed an EVA coating non-bio)
not true zero-order release: 60-70ug/day initially to 35-45 after 1 year to 25-30 end of 3rd year |
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Term
| insertion of implanaon nxt |
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Definition
local anaesthetic with device provided
removed by forceps 3 yrs later |
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Term
| pure implants (oestradiol) |
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Definition
treat hormone deficiency
compressed pure drug (nothing else)
admin minor surgical procedure
no removal required
release rate depend on SA
re-implant every 4-8 months
testosterone implants are similar
dose dumping not a concern |
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Term
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Definition
eye drops (aqueous or oily sterile solution, emulsion or suspension)
eye lotions: aqueous solutions used undiluted for bathing eye)
eye ointments: apply the conjunctival sac or margins of eyelids
contact lens : lub, clean and hydrate lens |
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Term
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Definition
| anaesthetics, anti-inflammatory, antiseptics, diagnostic, miotics, mydratics and artificial tears |
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Term
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Definition
sterile (P aeruginosa)
free from foreign particles
pain and irritation: unfavourable osmotic pressure, pH, medicament and preservative
viscosity: easy to filter, sterile, compatible |
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Term
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Definition
active ingredient
vehicle
preservative
adjuvants (pH, viscosity, tonicity)
suitable container |
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Term
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Definition
maintain stability and sterility
eyes are very susceptible to organisms especially cornea and damaged epithelia
for surgical use no need for preservative |
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Term
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Definition
benzalkonium Cl
chlorhexidine acetate or gluconate
chlorobutanol
organic mercurials |
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Term
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Definition
isotonic with lachrymal (0.9% NaCl)
can tolerate 0.7-1.5% NaCl
hypotonic need adjusting
hypertonic need avoiding
can use the FD1% method of adjusting tonicity w=0.52-a/b |
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Term
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Definition
increase viscosity-increase MRT-increase drug penetration_therapeutic effect
most products are 15-25mPas
a 50ul drop should drain from the conjunctival sac with 30 secs and no trace after 20 mins |
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Term
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Definition
hypermellose at 0.5-2% w/v
polyvinyl alcohol 1.4% w?v |
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Term
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Definition
lachrymal fluid pH7.22-7.4
pH offer stability during storage, therapeutic effect and comfort to patient
most are weak base salts
buffer agents: boric acid, phosphate buffer, citrate buffer |
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Term
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Definition
antioxidants for adrenaline, tetracaine
chelating agents: for heavy metals can catalyse breakdown of active ingredients by oxidation (disodium edetate 0.1%) |
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Term
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Definition
active ingredient added at end to final vol.
filtered in final container
terminal sterilised (so all parts of the final container need to withstand this) |
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Term
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Definition
| sterilised by ionising radiation prior to filling under aseptic conditions |
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Term
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Definition
natural: can withstand 115 at 30 mins
synthetic rubber: withstand dry heat, but not good for aqueous preparation because of water vapour permeable
rubber absorbs preservative and antioxidants during storage and autoclaving |
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Term
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Definition
autoclaving at 115/30 mins or 121/15 mins
membrane filter sterilisation: 0.22um pore
dry heat 160/2 hrs for non-aqueous |
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Term
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Definition
remain the principle route for local ophthalmic dd
limitations: barrier to solute flux provided by corneal epithelium
precorneal drug loss occurs by ay or tear drainage and turnover |
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Term
| problems with eye drops (ED) |
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Definition
<5% reaches intraocular tissues
major dose abs systemically thru conjunctiva and eye lid margins
more systemic abs occurs by way of nasolacrimal duct and nasopharyngeal mucosa |
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Term
| nasolachrymal drainage and ed |
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Definition
dilution by the lacrimal fluid, tear aided by blinking
low permeability of corneal tissue, low F 0.2-2%
loss thru the lacrimal duct and rolling down side of face |
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Term
| overall problems of topical ocular dosage forms |
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Definition
some can diffusion-dissolution and erode, but some can irritate and induce lacrimation-drainage-loss
once in tear film it can go 4 ways-irritation induced lacrimation or lacrimal turnover-drainage-loss or metabolism non-productive abs-loss or abs conjuncival-drug in aqueous humour and internal ocular structure-elimination |
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Term
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Definition
diabetes: crystalised lens
retina: blood vessel rupture
blind spots: increased fluid in eyeball
increased IOP: lens problem, iris dysfunction, vitreous humour gets cloudy, optic nerve damage |
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Term
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Definition
| rarely used, too much risk and to expensive |
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Term
| drug deliver for eye ball: |
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Definition
trans-corneal into anterior chamber: ED or ointments
across conjunctiva and sclera to anterior uvea: ED or ointments
via blood aqueous barrier to anterior chamber: systemic
drug leaving anterior chamber via: aqueous humour turnover
drug leaving via systemic circulation: uveoscleral
blood retinal barrier BRB (posterior): systemic
intravitreal drug adm: injection
posterior elimination: BRB
drug elimination via posterior to anterior: vitreous |
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Term
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Definition
harder to deliver, because of access and BRB
vitreous humour dilutes drug too much
drug metabolism
so systemic need high dose or injection into eyeball, but gets eliminated quickly |
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Term
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Definition
| DD to posterior chamber using dye and laser |
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Term
| problems with DD to posterior chamber |
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Definition
systemic: need high dose
ED: short contact time
injection: evasive and dilutes quick
photodynamic: limited and need injections |
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Term
| overcoming posterior chamber problems: |
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Definition
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Term
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Definition
blood aqueous barrier (BAB) and BRB are the blood ocular barrier: obstacle for tx for systemic meds (needs manipulation)
BRB: blood outward movement
BAB: blood into eye |
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Term
| eyeball delivery timeframe |
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Definition
ED and gels: hours-days
intraocular NP, MP & lipo: days-weeks
biograd implants and polymeric injections: weeks-months
nonbio implants years |
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Term
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Definition
no repeat injections
stabilization of drug
nonbio: more controllable delivery
bio: no need to remove |
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Term
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Definition
insertion is invasion and can have problems eg. retinal detachment, intravitreal haemorrhage
nonbio: need surgery to harvest device
bio: have a final burst in their drug release |
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