Lecture 12C - Topical Administration (Other locations) Flashcards
What formulation is used for nails?
solid formulations such as a nail lacquer
What is the structure of the nail?
hard keratinised structure
delivery through the nail plate is challenging
What is needed to increase diffusion of the drug through the nail plate?
keratolytic components such as urea
Example of nail treatment?
amorolifine (nail fungal infection)
What do keratolytic components do?
make the nail more porous and allows the delivery if the drug through the nail plate
What is the barrier to drug absorption in the eye?
caused by physiological and biochemical mechanisms (tears and blinking)
What must formulations applied to the eye be?
sterile
Most common formulation used in the eyes?
solutions (eye drops)
90% of ocular formulations
Advantages of eye drops?
easy to administer
homogenous (better dose uniformity)
Disadvantages of eye drops?
rapidly drained out of the eye (even with the presence of viscosity enhancers)
lack of efficacy
Example of a viscosity enhancer?
polyvinylalcohol
How long are eye drops retained in the eye?
90% elimination after 30 seconds
How much of a dose of eyedrops reaches the aqueous humour (site of action)?
1-5% of the instilled dose
Examples of eye drops?
chloramphenicol, ciprofloxacin (corneal ulcers)
Ointments for eyes?
mainly used of lipophilic excipients (petrolatum, lanolin)
Advantages of eye ointments?
reduce drug drainage caused by tear flow
increase of corneal residence time
sustained drug release (2-4h)
incorporation of drugs with poor aqueous solubility
Disadvantages of eye ointments?
more difficult to administer
more variable administered dose
blurring of vision (reduction in patient compliance)
Examples of eye ointments?
chloramphenicol, ciprofloxacin (corneal ulcers)
Administration to the ear?
solutions (ear drops)
Advantages of ear drops?
same as for eye drops
Formulation of ear drops?
viscous formulations (by adding glycerol, PEG)
increase of residence time of the formulation and prolonged contact with area of infection
Examples of ear drops?
chloramphenicol, clotrimazole for the treatment of ear infection (otitis)
Administration to the nose?
creams and ointments
removal of the drug from the nasal cavity
What do formulations administered to the nose need?
increasing nasal residence time by bioadhesion, increase formulation viscosity
ointments and creams
Examples of nose formulation?
mupirocin, chlorhexidine, neomycine (eradication of staphylococci)
Oropharyngeal administration?
solutions, gels, suspensions, mucoadhesive buccal tablets
What do suspensions do?
deposit antimicrobial drug on the mucosa surface, which improves the residence time of the drug but dissolution needed prior permeation
Examples of oropharyngeal administration?
miconazole gel and mucoadhesive tablets (fungal infections such as thrush, candidiasis)
nystatin suspension (fungal)
chlorhexidine mouthwash
Vaginal administration?
gels, creams, pessaries, ovules
What are pessaries?
vaginal suppository
solid, single dose formulations, of ovoid shape
What are ovules?
vaginal capsules, shell pessaries
solid, single dose formulations similar to an oral soft capsule, but their shape is often elongated
larger size ovoid
Advantages of vaginal administration?
treatment of local infections with a much lower dose than with oral administration
no need of absorption of the drugs for local action
Disadvantages of vaginal administration?
release of the drug is influenced by varying volumes of vaginal fluids
Examples of vaginal administration?
clotrimazole (cream, pessary)
antifungal miconazole (ovule)
metronidazole (gel)
What is glycerol?
helps to increase the residence time of ear drops
What is lanolin?
can be used to formulate eye ointments
What is urea?
keratolytic, which helps increase diffusion of drug through the nail plate
What is polyvinylalcohol?
viscosity enhancer, which helps to reduce the elimination of eye drops
