Pharmaceutical powders can be characterized using particle size distribution analysis. Mean or median particle diameters of pharmaceutical powders are often correlated to their dosage sizes and efficacy. Rapid particle size analysis by means of laser light scattering is often used to monitor pharmaceutical production.
Instrumentation and Experimental Procedure
High-resolution particle size distribution analyses can be rapidly performed using the Saturn DigiSizer®. This experiment demonstrates monitoring product quality by performing particle size analysis on commercially available powdered aspirin samples using the Saturn DigiSizer®.
Powdered aspirin samples were procured at different local pharmacies at different times in order to analyze different lots of powdered aspirin samples so that the differences between production lots can be determined. In addition, differences within a lot were assessed by analyzing a number of packets within the given lot.
Moreover, differences in particle size distribution between packages and brands from the same lot were analyzed by procuring two packages of a single lot of a second aspirin brand. Finally, multiple packets were investigated from both packages.
The Liquid Sample Handling Unit of the Saturn DigiSizer was filled with the samples in dry condition. Then, odorless mineral spirits were added to disperse the samples for two minutes by means of ultrasonic treatment utilizing the probe integrated into the Saturn DigiSizer®. The powder dispersion was aided by adding a small quantity of Micromeritics SediSperse A-11.
All samples were subjected to repeated analysis from three to eight times each. The average of the individual analyses were utilized in the below mentioned comparisons. The below mentioned control charts were generated using the SPC features of the DigiSizer software.
Figures 1 through 3 depict the control charts illustrating the analysis results for four packets obtained from each of three different lots of BC powdered aspirin, along with 3σ control limits and mean values.
Figure 1. Median diameter for 12 analyses of BC powder, 4 packets from three different production lots.
Figure 2. 90th percentile for 12 analyses of BC powder, 4 packets from three different production lots.
Figure 3. 10th percentile for 12 analyses of BC powder, 4 packets from three different production lots.
From the results, the variation between packets is more in the first lot (first four files) when compared to the other two lots, especially because of the second packet investigated from the first lot. The comparison of results obtained from repeated analyses of a single sample demonstrates the repeatability of the analyses.
An overlay of eight individual analyses of a packet of BC powder as well as the average of the eight analyses is presented in Figure 4.
Figure 4. Overlay of 8 individual tests of one packet of BC powder, along with the average result of the 8 tests.
Like the BC powder, six packets from each of two boxes of the same lot of Goody’s powdered aspirin were studied. Figures 5 through 7 show the control charts presenting the same statistics.
Figure 5. Median diameter for 12 analyses of Goody’s aspirin,6 packets from each of 2 packages of the same lot.
Figure 6. 90th percentile for 12 analyses of Goody’s aspirin, 6 packets from each of 2 packages of the same lot.
Figure 7. 10th percentile for 12 analyses of Goody’s aspirin, 6 packets from each of 2 packages of the same lot.
Figure 8 depicts an overlay comparing the particle size distributions for the BC and Goody’s aspirin powders.
Figure 8. Overlay of analyses of BC and Goody’s powdered aspirin.
The data presented in this article is not intended to compare the quality of the products analyzed. This data is provided to demonstrate the effectiveness of laser scattering particle size analysis in the characterization of these powders in order to monitor and control their production processes.
This information has been sourced, reviewed and adapted from materials provided by Micromeritics Instrument Corporation.
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