Skin and nail group

Overview

The skin is the largest organ in the human body and provides an essential barrier to prevent in ingress of chemicals in to the body and to prevent the loss of endogenous substances such as water from the body.

The skin is an attractive target for drug delivery for both local and systemic effects due to its large easily accessible surface area and the potential to avoid first pass metabolism.  

Nail disorders affect up to 10% of the population and range from innocuous discoloration of the nail plate, commonly seen in smokers, to chronic infections, which can be very painful and disfiguring for the sufferer.

Nail infections are especially serious for immunocompromised patients and diabetics where they can cause major complications such as limb amputation.

There are many highly effective compounds available to treat infections found in the nail but, the ungual keratin represents a highly effective barrier against absorption following topical drug administration, and therefore, the delivery of therapeutic agents to the site of action, ie within the nail plate and the nail bed, represents a significant challenge.

At present, topical treatments used for nail disorders such as fungal infections or psoriasis require long-term application, hence patient compliance is often poor and relapse common.

  The Group is part of the Research Centre for Topical Drug Delivery and Toxicology (TDDT).

What the group does

As part of the TDDT research centre we have successfully developed a centre of excellence for topical drug absorption screening drawing on the expertise of many members of the pharmaceutics team and colleagues from other disciplines.

The centralisation of this knowledge and experience, as well as the availability of excellent research facilities and equipment has led to many successful research grants and publications. In addition an in vitro testing laboratory has been established which has a strong track record of producing high quality data to the principles of GLP, for a range of commercial clients.

Services offered include:

• formulation optimisation
• release testing
• franz cell experiments
• permeation studies using radiolabelled substances.      

Complementary characterisation analysis of formulations can also be performed including rheological testing, differential scanning calorimetry (DSC), Raman microscopy and ATR-FTIR spectroscopy.

In summary, our activities currently include:

• Formulation optimisation
• Release testing
• Franz cell experiments
• Radiolabelled permeation studies
• Ungual permeation studies
• Clinical research trials (topical formulations)

Key projects

A fundamental study to determine the difference in barrier properties of healthy and diseased nail in order to aid the development of ungual drug delivery systems

BBSRC/ MRC funded three-year post doctoral research position. This prestigious grant was awarded to a collaboration of universities headed by the School of Pharmacy, University of Hertfordshire in collaboration with the School of Pharmacy, University of London and Division of Pharmaceutics, King's College London. Together these institutions form an internationally-recognised centre of excellence in the research of nail disease.  

Skin permeation of nanoparticles using a flexing skin model

This Health Protection Agency funded PhD studentship is investigating the potential for nanoparticles, such as titanium dioxide and zinc oxide from sunscreens to be absorbed in to the skin. 'Sebum as a biomonitoring matrix'. The objectives of this internally-funded project are to establish the normal mixture of chemicals present on the skin surface and to subsequently identify the presence of individual chemicals which may be indicative of disease states or exposure to environmental pollutants.  

Prediction of skin irritation and sensitisation using an ex vivo skin culture model

In collaboration with MedPharm Ltd this project is developing a model using excised human skin to predict the irritancy index and degree of sensitisation of topical excipients, APIs and formulations. The model is intended to reduce the need for animal testing thus presenting a cheaper, quicker and more ethically acceptable technique to existing models such as the Draize test. It advances current in vitro alternatives through its use of actual human skin and the combination of permeation and mechanistic parameters.   

Tamperproof transdermal formulation development

This industrially-funded PhD studentship seeks to design transdermal formulations which can resist the extraction and abuse of an active drug contained in the formulation. Abuse of prescription medications is a serious issue and this project intends to develop a platform that can be used to limit this for transdermal formulations improving the product safety.

Development of a novel heat producing system for dermal drug delivery

Often the barrier properties of human skin make it difficult to develop medicines that are capable of delivering sufficient quantities of drug across the skin. One strategy to improve this is the application physiologically tolerable heat to improve drug permeation across the skin.

This Medpharm Ltd funded PhD studentship seeks to explore the effects of heat on the delivery of different model drugs across skin and to develop a suitable platform which can use heat to improve therapeutic treatment.

Contact details

Please contact Matt Traynor by email or by post: Department of Pharmacy, University of Hertfordshire, Hatfield, AL10 9AB, UK.