P6

What is the Eustachian tube?

Tube that connects to the inner ear and runs to throat

Define Otitis media?

Common ear infections, build up of fluid and inflammation

Define Meniere's disease?

Vertigo

How are middle ear infections usually treated?

Systemically

How are inner ear infections treated?

Not systemically

What is the first line of defence in the ear?

Tympanic membrane

Describe the outer layer of the Tympanic membrane?

keratinised epithelium, that is slowly moving up and becoming flatter

Describe the middle layer of the Tympanic membrane?

Collagen-rich layer, provides structure support, flexibility to accommodate pressure

Describe the inner layer of the Tympanic membrane?

Cuboidal mucosal epithelium

What is the Tympanic membrane soluble to?

Mainly lipophilic membrane

What is ear wax made up of?

Sebum, skin cells, sweat and dirt

What is the function of ear wax?

Protective coating and trap particulates

How is the ear wax protective?

Moves particulates away from TM via the hair and is acidic so bacteria can’t grow

What is ear wax impaction?

When ear wax gets trapped in the narrow auditory canal via the overproduction of cerumen or it is pushed in there?

What can ear wax impaction lead to?

Increases residence time for toxic particulates leading to tinnitus, vertigo and ear pain, live insects can cause issues

Describe treatment for ear wax?

Olive oil or sodium bicarbonate to soften wax

What types of TM perforations are there?

Acute/chronic wet/dry

What is the likely outcome if the TM perforation is acute and wet?

Heals quickly, a few weeks, responds to topical therapies

Summarise that natural healing process of TM?

Epidermis closes first, flooding of cells and growth factors, fibrous layer reconstruction, maturation, long term remodelling

How to treat a chronic TM perforation ?

Needs surgery using grafts

What is the auditory organ?

Cochlear contains hair cells that movements generates nerve impulses that transmit to the brain

What are the organs of balance?

Vestibular systems

How drugs reach the inner ear?

Drugs travel through the round window but distribution depends on inner ear fluids and the other barriers

Why are children’s ear medication different to adults?

The difference is in administration due the difference in shape of ear canal

Describe the methods that can get drug across TM?

Non invasive diffusion into the middle ear, Invasive injection/device crossing TM, Invasive drug delivery on RM allowing diffusion of drug to inner ear

What do otic drug formulations aim to do?

Increase residence time using things such as hydrogels and nano particles, use of chemical permeation enhancers to enhance flux

What types of drugs are administered as topical formulations for the ear?

Antibiotics, antifungals, gels and foams

Advantages of topical otic formulations?

Have good patient compliance, high concentrations locally not systemically allowing mixture of treatments, work rapidly

Disadvantages of topical otic formulations?

Ototoxicity with high concentration, over time

Define ototoxicity?

Adverse reaction to drugs affecting inner ear or auditory nerve via degeneration, affects cochlear or vestibular systems

Name some of the non-invasive delivery systems?

Hydrogels, chemical permeation enhancers, nanocarriers, peptides

Describe topical hydrogels benefit?

Prolongs release via reverse thermal gelling

Describe topical chemical permeation enhancers benefit?

Increases flux across barriers via surfactants and changes to pH and absorption

Why are topical nanocarriers beneficial?

Are less than one micron so can pass through barriers

Describe how invasive hydrogels can be useful?

Clearance via Eustachian tube can be avoided

Name invasive techniques for otic drug delivery?

Hydrogels, nanoparticles, ultrasound, pump/catheter

Describe how invasive nano particles can be useful?

Can be pH sensitive as pH of inflamed tissues is different, can modify their surface to have enhanced permeation properties

Describe how an invasive pump/catheter can be useful?

Precision control of drug release and a programmable device