Dena System Performance Test on ‘Formulation A1' by Durham University
The Dena system was used by a major pharmaceuticals manufacturer during tests on a new formulation. System performance was measured by the size distribution characteristics of resulting batches after different milling periods. All particle size data was provided by a Malvern laser particle sizer package.
Sample Preparation The material processed, ‘Formula A', was composed of the following:
- Methocel E5-50g
- Sodium Lauryl Sulphate-2g
- Drug-100g
- Purified Water-1000ml
For each trial, a pre-milling slurry was prepared by stirring the ingredients vigorously together.
Method
The Dena system used features D3, S2 & SS reactors and the SPS polishing system. It was powered by compressed air at 84psi maximum; the material was pumped through the system by a 1:1 ratio diaphragm pump.
Five samples of identical raw material were processed during the trial. One sample of raw material was kept for reference. The samples were processed for a single pass, and 15, 30, 120 & 240 minutes respectively.
Results
The figure below shows the particle size distribution of each sample, after the respective period of milling, the Dena system made the size distribution of the particles significantly narrower. The narrow width of the distribution makes the drug more bio-available, allowing smaller doses and faster, more accurate ingestion and treatment.
Analysis
The Microsoft Excel spreadsheet package was used to analyse the particle size data from the Malvern sizer and to produce Figure 1, Excel was also used to produce standard d10, d50 and d measurements, the most pertinent of which are shown below.
Milling Times (mins) d50 Width (d90-d10)
Raw Materials 35.41 microns 243.52 microns 240 mins 0.37 micron 0.64 micron
Conclusion
After 240 minutes of milling, the Dena system reduced Formula A1 to the indicated particle size range. The extremely narrow size distribution obtained created a 300% increase in the drug's bioavailability, compared to that obtained through conventional milling.