3M Drug Delivery Systems 3 Chris Blatchford & Gemma Nixon, 3M Drug Delivery Systems, Morley St, Loughborough, UK. Graham Hargrave, Tim Justham & Edward Long, Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, UK.. Text Here – Body copy will vary in size depending on how much text you have to fill the whole poster NOTE* - You cannot reduce your Body Copy smaller than 12 pt type on this template. Two analytical techniques, high speed laser imaging and plume force measurements have been investigated for measuring the ex-actuator plume from pulmonary and nasal products. The advantages and disadvantages of the techniques are discussed with an analysis of data from a range of marketed products. 3M Drug Delivery Systems An Evaluation of Analytical Techniques for Characterising the Plume Velocity and the Plume Force of Pulmonary and Nasal Products The authors would like to thank Mark Copley for helpful discussions and for the loan of a Copley SFT1000 Spray Force Tester Gabrio B, Stein S and Velasquez D. A New Method to Evaluate Plume Characteristics of Hydrofluoroalkane and Chlorofluorocarbon Metered Dose Inhalers. International journal of Pharmaceutics, Volume 186, Issue 1, 10 September 1999, Pages Guo C and Doub W. Development of a Novel Technology to Measure impaction Force of Nasal Sprays and Metered Dose Inhalers Using the Texture Analyser. Respiratory Drug Delivery Leading edge velocity and spray force measurements are both useful analytical techniques for the characterisation of spray plumes and this has been demonstrated on a wide range of commercially available inhalation products. The data from three pMDI products show that both plume force and leading edge velocity measurements have detected similar trends i.e. those plumes with a higher leading edge velocity tend to have a higher spray force. Leading edge velocity measurements require sophisticated research equipment and customised software which is not available as a commercial product. The Copley Scientific SFT1000 Spray Force Tester is much easier to use and is a less costly option, however there were some imitations including the vibration of the instrument when the operator presses the buttons or actuates the MDI and from the resonance frequency in the force sensor. Header Here - light blue background Spray Force Experimental The Copley Scientific SFT1000 Spray Force Tester has an integrated Mecmesin AFG 2.5N Force sensor which records the spray force from the evolved plume. During initial testing it was found there was mechanical interference both actuating the unit and pressing the tare button on the force sensor. The instrument was used in a modified configuration with the force sensor and plate re-positioned so they were facing in the opposite direction and the actuator held in a separate jig, as shown in Figure 1. High Speed Laser Imaging Experimental Conclusions Figure 1 – Spray Force Tester Modified Set-Up The Spray Force Tester can be set up in two modes, either to measure the maximum force over the duration of the spray plume, or a high speed analogue output. High speed analogue data capture showed that when a force was applied to the plate there was a resonance set up in the sensor at about at about 1kHz. This resonance interfered with the high frequency force of the plume and therefore all further studies were performed with the instrument in maximum force mode. The equipment was used to analyse a wide range of commercially available pMDI products (Figure 2) and nasal spray products (Figure 3) at a firing distance of 5cm using 3 shots from 3 devices for each product (n=9). Three pMDI products were also measured at 3cm, 5cm and 7cm (Figure 4) for comparison with the leading edge velocity experiments. The pMDI units were held at an angle so that the plume had a horizontal trajectory. The actuation was triggered by a solenoid valve with a compressed air supply held at 60psi. The trigger was also synchronised to start the video camera. The high resolution images were transferred to a PC and the digital data manipulated using specifically designed in-house software. Software algorithms were set up to follow the leading edge of the ex-actuator plume over the first 10 cm and the distance/time data was converted into distance/velocity data as shown in Figure 5. The spray force data showed that there was a very high range of forces for different products and there was a large overlap in the plume forces for pMDI and nasal spray products (Figures 2 and 3). Figure 2 – Spray Force of pMDI products Figure 3 – Spray Force of nasal spray products The data from three selected pMDI products also show that measurements can be taken at different distances and there is obvious consistency of the data at the different distances (Figure 4). The Leading edge velocity data gives a better indication of the way the plumes from different pMDI products dissipate with distance (Figure 5). Some devices have plumes with leading edge velocities of more than 20 msec -1 when close to the actuator but at a distance of 5 cm these have typically reduced to below 15 msec -1. Product B has consistently lower plume force and leading edge velocity between 3 and 7 cm firing distance, whereas Product C has the highest force and the highest leading edge velocity. Figure 4 – Peak Spray Force using Copley Scientific Spray Force Tester for Products A, B and C Figure 5 – Leading edge velocity by High Speed Laser Imaging for Products A, B and C A method was developed using a pulsed laser (20nsec pulse width) and a synchronised high speed video camera to record images of the ex-actuator pMDI plume at a frequency of 10kHz. The laser beam was configured as a vertical sheet of light which passed through the ex-actuator plume in the opposite direction to the plume trajectory. The plane of light was aligned slightly in front of the nozzle so that any heating affects caused by the high intensity light source would not affect the atomisation process or distort the actuator orifice. The video camera was focused precisely on the laser light plane. Results Introduction Conclusions Acknowledgements and References