Module 2l-Otic delivery systems

Question 1

What effect does swimming have on the external auditory canal?

Answer 1

It causes hydration of the keratin layer, increasing susceptibility to pathogenic organisms. Because as most organisms responsible for otitis externa and chronic superlative otitis grow best at alkaline pH(7.2-7.6).

Question 2

Discuss the formulation requirements for the ideal cerumenolytic preparation?

Answer 2

The ideal cerumenolytic preparation (a hypo-osmolar, alkaline, aqueous solution) has not been developed yet. It should be able to lyse keratin cells of the cerumen and allow for easy disimpaction.

Question 3

What type of otic dosage for, is not likely to cause pain on administration?

Answer 3

Powder preparations

Question 4

Discuss the significance of ototoxicity with respect to otic drug delivery systems?

Answer 4

Ototoxicity is of most concern when there is a perforation in the tympanic membrane-
Ototoxic drugs
Antiseptics, antibiotics, neomycin, chloramphenicol
No Ototoxicity
Quinalones, corticosteroids
The risk of hearing loss resulting from otitis media is generally higher however than from an Ototoxic agent. Risk increased in perforated ear drum.

Question 5

Describe how the various glands in the external auditory canal provide antimicrobial activity?

Answer 5

The s-shaped anatomy of the EAC provides protection from foreign bodies. EAC is normally has a isoelectric point of acidic (pH 4-5) because of keratin which consists of desquamated epithelium cells. All these help in reducing foreign bodies and infections.
Glands
Sweet glands-release muramidase a lysozyme which is effective in lysing staphylococcus epidermis and other G+ found on the surface of the ear canal.
Sebaceous glands- release Unsaturated fatty acids from the breakdown of lipids-antimicrobial G- and anti-fungal