PSD Method Validation or Particle Size Method Validation guidance is provided here for Pharmaceutical professionals and Pharma Industry.
Particle Size Distribution (PSD) Introduction
“PSD (Particle size distribution)” is an index (means of expression) indicating what sizes (particle size) of particles are present in what proportions (relative particle amount as a percentage where the total amount of particles is 100 %) in the sample particle group to be measured. Laser diffraction methods are used for Particle size distribution.
These methods depend upon an analysis of the “halo” of diffracted light produced when a laser beam passes through a dispersion of particles in the air or in a liquid. The angle of diffraction increases as particle size decreases so this method is particularly good for measuring sizes between 0.02 and 2000μm. This technique is relatively fast and can be performed on very small samples.
A particular advantage is that the technique can generate a continuous measurement for analyzing process streams. Laser diffraction measures particle size distributions by measuring the angular variation in the intensity of light scattered as a laser beam passes through a dispersed particulate sample. Large particles scatter light at small angles relative to the laser beam and small particles scatter light at large angles. The angular scattering intensity data is then analyzed to calculate the size of the particles responsible for creating the scattering pattern, using the Mie theory of light scattering.
PSD Method Validation Procedure
The PSD Method Validation procedure is commonly two types (Wet & Dry). The procedures are provided here for easy understanding.
Particle Size Distribution Wet Method Validation
The PSD Method Validation procedure and parameters for the Wet method was given below.
Precision:
It is the degree of reproducibility or repeatability of the method.
Reproducibility:
Reproducibility is measured by taking 6 consecutive measurements for 6 preparations of the same sample.
Perform the sample analysis as per the Method of analysis.
Repeatability:
Repeatability is measured by taking 6 consecutive measurements for a single preparation of the sample. Perform the sample analysis as per the Method of analysis.
Calculate the %RSD at 10%, at 50%, and at 90%.
The % RSD should be followed as per USP <429>.
Ruggedness/ Intermediate precision:
It is the degree of the method with inter-laboratory variations with the same experimental parameters.
Demonstrate and perform the repeatability and reproducibility exercises with the second analyst on another day.
Perform the sample analysis as per the Method Validation protocol.
Calculate the %RSD At 10%, At 50%, and At 90%.
The %RSD should be followed as per USP <429>.
Solution Stability:
The sample was prepared as per the Protocol and measured at Initial (`O’ min), 5 min, 15 min, 30 min, 45 min, and 60 min individually. Calculate the %RSD at 10%, at 50%, and at 90% and observe the stability of the sample-dispersed solution.
The %RSD should be followed as per USP <429>.
Batch Analysis:
Take a minimum of two batches and prepare the sample as per the STP.
Analyze the batches each once and tabulate the results.
Refer to the attached model Method Verification Protocol for the Wet technique.
Particle Size Distribution Dry Method Validation
The PSD Method Validation procedure and parameters for the Dry method was given below.
Precision:
It is the degree of reproducibility of the method.
Reproducibility:
Reproducibility is measured by taking 6 consecutive measurements for 6 preparations of the same sample.
Perform the sample analysis as per the Method of analysis.
Calculate the %RSD At 10%, At 50%, and At 90%.
The %RSD should be followed as per USP <429>.
Ruggedness/ Intermediate precision:
It is the degree of the method with inter-laboratory variations with the same experimental parameters. Repeatability and reproducibility exercises can demonstrate by performing with a second analyst on another day. Perform the sample analysis as per the Method Validation protocol.
Calculate the %RSD at 10%, at 50%, and at 90%.
The %RSD should be followed as per USP <429>.
Batch Analysis:
Take a minimum of two batches and prepare the sample as per the STP.
Analyze the batches each once and tabulate the results.
Read never before articles only at Pharmaelix Particle Size Wet Method Latest Guidance, Particle Size Dry Method Latest Guidance 2023
PSD Method Validation and Conclusion
Make a consolidated conclusion report, by including any precaution statements if applicable.
Note: If more than one method (For Example Milled, Micronized, Non-Micronized) is available for the same product, each method shall validate separately.
Validation laser diffraction particle size reference
As per USP <429> USP method validation, the %RSD is as follows.
If the material has d (0.5) > 10µm then the %RSD for d (0.1), d (0.9) should not be more than 15% and d(0.5) should not be more than 10%.
If the d (0.5) <10µm these maximum values are doubled.
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