Quiz
MD14 Routes of delivery: Occular
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Perguntas do quiz (12)
1Choose the incorrect statement.
- AThe sclera is tough and avascular, and the thickest layer.
- BThe choroid is a fatty layer under the sclera that is vascular.
- CThe retina is thin and light sensitive.
- DThe cornea adjoins the sclera and is vascular.
2[blank_start]Topical[blank_end] eye disorders: Conjunctivitis, blepharitis, dry eye, infections
[blank_start]Anterior to lens[blank_end] disorders: Corneal infection, iritis, glaucoma, cataracts
[blank_start]Posterior lens[blank_end] disorder: Viral retinitis- ATopical
- BAnterior to lens
- CPosterior lens
3Typical ingredients in OTC ocular formulations:
• [blank_start]Active[blank_end]: eg Pilocarpine, naphazoline
• [blank_start]Vehicles / lubricants[blank_end]: eg Dextran, gelatin, propylene glycol
• [blank_start]Preservatives[blank_end]: eg benzalkonium chloride, sorbic acid
• Excipients: [blank_start]Wetting[blank_end] agents, [blank_start]buffers[blank_end] and [blank_start]tonicity[blank_end] adjusters- AActive
- BVehicles / lubricants
- CPreservatives
- DWetting
- Ebuffers
- Ftonicity
4Choose the incorrect statement
- AOne of the main advantages of ocular topical delivery is that lower doses are required and it is painless.
- BThe main disadvantage of ocular topical delivery is that bioavailability is low.
- CTopical ocular delivery is effective for posterior eye segment.
5Ocular fluid or 'tears' come from the lacrimal gland which can store about [blank_start]7 microlitres[blank_end] of fluid. The tears are [blank_start]pH 6.9 - 7.4[blank_end], have a [blank_start]low[blank_end] buffer capacity, and contain [blank_start]lysozymes[blank_end]. Tears are not uniform and the tear film model shows that mucins like [blank_start]glycocalyx[blank_end] are concentrated by the corneal epithelia, and generally becomes more [blank_start]aqueous[blank_end] with soluble mucins. There is a [blank_start]lipid[blank_end] layer at the surface.
- A7 microlitres
- BpH 6.9 - 7.4
- Clow
- Dlysozymes
- Eglycocalyx
- Faqueous
- Glipid
6Max volume for eye = [blank_start]30 microlitres[blank_end]. Exceeding this volume causes spillage and [blank_start]loss[blank_end] of dose.
Ionised drugs are [blank_start]more likely[blank_end] to be cleared by the aqueous tears as they are [blank_start]more soluble[blank_end].
There is [blank_start]drainage[blank_end] via the nose to the GIT so there could be potential systemic [blank_start]side effects[blank_end], as well as this makes [blank_start]taste[blank_end] of formula a factor.- A30 microlitres
- Bloss
- Cmore likely
- Dmore soluble
- Edrainage
- Fside effects
- Gtaste
7A hydrophilic drug is more likely to pass through the cornea faster than a hydrophobic drug.
- AVerdadeiro
- BFalso
8Choose the incorrect statement about conjunctival-scleral absorption.
- AWe must consider the loss of dose to systemic circulation due to conjunctival vasculature and large surface area.
- BMay be important for small, polar compounds
- CEye drops will have a short residence time
9Optimizing topical ocular drug delivery systems:
1. Good corneal [blank_start]penetration[blank_end]
2. Prolonged [blank_start]contact time[blank_end] with corneal epithelium
3. Simple [blank_start]application[blank_end] for patient
4. [blank_start]Non-irritating[blank_end]
5. Appropriate [blank_start]molecular weight and properties[blank_end] for API- Apenetration
- Bcontact time
- Capplication
- DNon-irritating
- Emolecular weight and properties
10Formulation strategies to improve topical ocular bioavailability:
1. [blank_start]Decrease volume[blank_end] of instillation (<10microlitres)
2. [blank_start]Formulate to minimise irritation[blank_end] (buffer at pH 6.9-7.4, make isotonic)
3. I[blank_start]ncrease retention time[blank_end] (viscosity enhancing polymers, thixotropic rheological properties, gel formation)- ADecrease volume
- BFormulate to minimise irritation
- Cncrease retention time
11Ointments have a prolonged contact time because of viscosity but are not well accepted due to discomfort and interference with vision.
- AVerdadeiro
- BFalso
12Drug delivery to eye posterior:
1. Systemically: need [blank_start]high[blank_end] doses, risk [blank_start]side effects[blank_end], limited value for posterior delivery
2. Topically via cornea: accessible, but many [blank_start]loss factors[blank_end], [blank_start]low[blank_end] bioavailability
3. Injections
a) Intra-vitreal: injections need to be [blank_start]frequent[blank_end](poor compliance), lens damage risk, bleeding, [blank_start]infection[blank_end] risk
b) Sub-conjunctival injection for [blank_start]trans-scleral[blank_end] absorption
c) Retro-bulbar injections (usually for opthalmic local [blank_start]anaesthetics[blank_end])
4. Intra-vitreal inserts: surgically inserted, [blank_start]sustained release[blank_end] (5 - 8 months), [blank_start]biodegradable[blank_end] polymer- Ahigh
- Bside effects
- Closs factors
- Dlow
- Efrequent
- Finfection
- Gtrans-scleral
- Hanaesthetics
- Isustained release
- Jbiodegradable
Informações
- Descrição
- PHCY211 (Medicines) Quiz sobre MD14 Routes of delivery: Occular, criado por Mer Scott em 19-05-2018.
- Autor
- Mer Scott
- Idioma
- English
- Visualizações
- 6
- Histórico
- Criado em 19 mai 2018 · atualizado em 19 mai 2018
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