Drug inhalation technologies: delivering medicines without injections
Incurable respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), are on the increase. The World Health Organisation (WHO) estimates the number of asthma sufferers at around 300 million and the number of COPD sufferers at 210 million, worldwide.
Research teams in our Centre for Drug Formulation Studies have developed treatments which help control symptoms and increase the quality of life for sufferers.
Inhaled pharmaceuticals – the challenge
Drugs delivered through an inhaler go directly into the airways, but the particle size is crucial. A dose larger than 10μm (or 10 thousandths of a millimetre) will be swallowed and never reach the lungs. Anything smaller than 1μm is exhaled. So the optimal particle size is between 2 and 5μm, but these particles can adhere together to form agglomerates much larger than the critical 5μm.
Overcoming particle adhesion
In the 1990s, research at our Centre for Drug Formulation Studies resulted in significant progress in overcoming the issue of drug-drug particle adhesion by including pharmacologically inactive materials within the formulation to modify how individual drug particles interact. Old-style inhalers delivered approximately 20% of the dose to the respiratory tract – but the amounts varied. The use of inert carrier particles means that around 50% of the dose is now delivered, consistently.
Vectura Group plc
Vectura Group plc originated from this research and is focused on the development of pulmonary products using its proprietary inhaler device and formulation technologies. The company has eight products marketed by its partners and a portfolio of drugs in clinical and pre-clinical development, some of which have been licensed to major pharmaceutical companies.
In July 2010, Vectura signed a dry powder formulation licensing deal with GlaxoSmithKline worth £20 million in up-front and milestone payments, as well as royalties on product sales.
Some of the original research team are now back at the University of Bath working on transdermal and topical drug delivery. Developments include a novel tablet which delivers a metered dose of a drug when applied to the skin via an applicator and gentle rubbing. This provides a less messy and more accurate way of administering drugs than creams.