Formulation of Advanced or Complex Medicines 23 Flashcards
Why are organic mercurials used as preservatives in eye drops?
Effective against most bacteria and fungi
What are the disadvantages of using organic mercurials as preservatives in eye drops?
Mercury deposition
Allergy
Hypersensitivity to thiomersal
- prolonged use not recommended
What are the advantages of using organic mercurials as preservatives in eye drops?
Non-irritant
No tear film disruption
Why is chlorbutol used in eye drops as a preservative?
Effective at 0.5% against most bacteria and fungi
Well tolerated
Compatible with most drugs
- but NOT fluorescein
What are the problems with using chlorbutol as a preservative in eye drops?
Volatile
Only stable in acidic solution
Does not withstand autoclaving
What are the pharmacopoeial requirements of eye drops?
Solutions should be practically clear and particle-free
Suspensions are suitable dispersed and comply with Particle Size Test
Multidose container contain a suitable antimicrobial preservative at appropriate concentration
If not prescribed with a preservative product, should be supplied as a single-dose container
Multi-dose containers should contain maximum of 10ml
- unless justified and authorised
Storage in tamper-evident containers of compatible components
Approved code names can be used on single-dose units
Label states single use only or, for multi-dose, the period after which contents should be used
- should not exceed 4 weeks
- 28 days
What are semi-solid eye preparations?
Sterile ointments, creams or gels intended for application to the conjunctiva or to the eyelids
Why are eye ointments used, compared to drops?
When prolonged duration of activity required
What are eye ointments made of?
Usually paraffin base, with melting temperature close to body temperature
- drugs incorporated into oily phase, aqueous phase or as a fine powder
What other excipients might be included in eye ointments?
Dispersants
- to disperse into aqueous phase
Stabilisers
- to improve stability in aqueous phase
Preservative
- antimicrobial preservation
Give examples of water based gelling agents used in eye ointments
Polyacrylic acid
Hypromellose
Carbomer
How does the base used control the viscosity of the eye ointment?
Proportions of Yellow Soft Paraffin, Liquid Paraffin and Hard Paraffin may be varied
- cold climates
- hot climates
But the active ingredients must remain the same
How are semi-solid eye preparations packaged?
Packed in small, sterilisable, collapsible tubes fitted or provided with a cannula and having a content of < 10g
- unless larger can be justified
Container must be tamper evident and facilitate administration without contamination
How should semi-solid eye preparations be stored?
Storage at <25C unless otherwise stated
Label states the period after which contents should not be used
- should not exceed 4 weeks
- 28 days
What is an eye lotion?
Sterile, aqueous solutions intended for use in rinsing or bathing the eye or for impregnating eye dressings
