New test system will speed development of inhalers and drugs

VariDose, an optical instrument that speeds up the measurement of drug inhaler performance, has been developed by anglo-american company Cambridge Consultants and is being launched in Edinburgh at the 'Drug Delivery to the Lungs' exhibition and conference on 7 - 9 December 2005.

The instrument, which is to be marketed by the UK-based company VariDose, employs opto-electronics and takes less than 60 seconds to run each test. It enables drug delivery and pharmaceutical companies to quickly and efficiently test a wide range of drug-device combinations at the development stage, without relying on standard inhaler testing methods.

Heightened interest in innovative pulmonary drug delivery is being fuelled by the emergence of inhaled systemic drugs and global concern over the rise in respiratory conditions such as asthma and chronic obstructive pulmonary disease.

The device provides additional valuable information on the detailed characteristics of the particle or droplet cloud emitted by the inhaler and can also be positioned in-line with other measurement devices, a breathing simulator or a patient.

VariDose measures the cloud of drug released from an inhaler as it passes through a tube intersected by co-planar beams of red, blue and infra-red light. Sensors are able to monitor the structure of the evolving drug cloud as the light passes through. Detailed analysis is then presented on a standard Windows-enabled PC or laptop. Results can be used to investigate essential cloud characteristics related to variability in particle size distribution, fine particle frac-tion and dose to pinpoint how design modifications could improve both drug and device effectiveness.

'Current measurement systems, such as cascade impactors and impingers, have been around for over 20 years and are inflexible and labour intensive. The use of VariDose during r&d will dramatically increase the efficiency of the development process,' said Peter Smith, Professor of Photonics at Loughborough University and co-inventor of VariDose, with Dr Olga Kusmartseva.