Murdan, S

UCL Discovery

Painting Medicines on the NailWhile nail cosmetics abound, medicines that are applied to the nail are few and far between, eventhough nail diseases are not uncommon. And because the nail (at least the fingernails) is part of ourphysical appearance, nail diseases affect not only their function, but also our day-to-day interaction withothers. A remarkably wide range of afflictions can affect the nail and alter its size, shape, colour,integrity, mechanical strength, growth, its attachment to the underlying tissue, as well as causeinflammation of the skin surrounding the nail. Some of these only pose minor cosmetic concerns suchas white spots on the nail which grow out with the nail, while others, e.g. infections caused by ingrowntoenails cause considerable distress. Still, other nail disorders are not limited to the nail, but aresymptoms of more serious, internal disease. For example, nail clubbing where the nail is excessivelyovercurved and the fingertip mass is increased, can be a sign of problems with the lungs. Changes in thenail can also be caused by medication (taken for other diseases). Obviously, in the latter two instances,treatment of the other disease or a change in the nail-altering medication should alleviate the nailproblem.The most common nail disease is fungal infection, which affects between 10 to 40% of the population. Itfollows therefore that most nail medicines that are applied to the nail are for this indication. In the UK,the most recent is Curanail (also called Loceryl®) which is a nail varnish containing drug. Once appliedonto the nail, Curanail dries within a few minutes and a transparent film is formed on the nail. The anti-fungal drug then moves out of the film and into the nail. Unfortunately, because the nail is not verypermeable, only a very small percentage of the drug that is present in the film penetrates into the nail,and Curanail is only recommended in early or mild infection in up to 2 nails, or when only the nailsurface is affected or when the patient cannot take other antifungal drugs by mouth. Curanail is applied1-2 times weekly, for 6 months for fingernails and 9-12 months for toenails. In addition to Curanail,Trosyl® and Phytex® are also available in the UK, though Trosyl® can only be obtained on prescriptionand Phytex® is thought to be less suitable. Like Curanail, these liquids are only recommended in milddisease and are applied on the nail for a very long time. Unlike Curanail however, they are applied twicea day, as they are easily removed during normal daily activities such as washing.I mentioned earlier that medicines for application to the nail are few and far between. This situationmay soon change as many more pharmaceutical scientists and companies are now working in this field.The nail varnish remains a popular choice as a drug carrier, although other types of formulations, suchas, patches and films, are also under investigation. The major challenge is to substantially increase theamount of drug that enters the nail, so that treatments can be shorter and more successful than existingmedicines. To this end, scientists are exploring using electricity, sound waves, lasers, acid and otherchemicals, as well as drilling holes into the nail. Electricity pushes more drug into the nail, while theother techniques damage the nail to certain extents, allowing more drug to enter. Obviously, the levelof these enhancers would be sufficiently low so that the patient suffers no discomfort. Research intothese avenues is exciting, although much more funding is needed to bring new and more effective nailmedicines to patients.Dr Sudaxshina Murdan, The School of Pharmacy, 29-39 Brunswick Square, London. Dr Murdan isresearching a number of methods to increase drug penetration into the nail.

Painting Medicines on the Nail

http://discovery.ucl.ac.uk/1351482/1/1351482_Nail%20Medicines.pdf

Painting Medicines on the Nail

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