after preparing of nanocapsules and determining of size and PDI value, I want to know how to interpret value
(PdI) = the square of the standard deviation / mean diameter. For example, a
particle with a Z-Average value of 100 nm and a PdI of 0.1 would have a standard deviation of 31.6 nm.
PDI value ragnges from 0-1 and indicates:
0-0.08 : Nearly monodisperse sample
0.08 to 0.7: Mid-range value
0.7-1: very broad distribution of particle sizes
In case of pharmaceutical nanoparticles, PDI below 0.3 is desired
useful links:
http://149.171.168.221/partcat/wp-content/uploads/Malvern-Zetasizer-LS.pdf
http://50.87.149.212/sites/default/files/nanoComposix%20Guidelines%20for%20DLS%20Measurements%20and%20Analysis.pdf
(PdI) = the square of the standard deviation / mean diameter. For example, a
particle with a Z-Average value of 100 nm and a PdI of 0.1 would have a standard deviation of 31.6 nm.
PDI value ragnges from 0-1 and indicates:
0-0.08 : Nearly monodisperse sample
0.08 to 0.7: Mid-range value
0.7-1: very broad distribution of particle sizes
In case of pharmaceutical nanoparticles, PDI below 0.3 is desired
useful links:
http://149.171.168.221/partcat/wp-content/uploads/Malvern-Zetasizer-LS.pdf
http://50.87.149.212/sites/default/files/nanoComposix%20Guidelines%20for%20DLS%20Measurements%20and%20Analysis.pdf
In pharmmaceutical PDI should be less than 0.3 indicate monodispersity.
more than 0.3 indicates polydispersed.
according to various literature we are following.
(PdI) = the square of the standard deviation / mean diameter
As PdI as dimensionless, it cannot be defined as Saed Abbasi stated, for it would be a number of nanometers.
The actual definition of PdI according to Malvern (referring directly to the ISO 13321:1996 norm) is based on the Cumulants analysis that is performed to fit the correlation function: Ln(C(tau))=a+b*tau+c*tau², a third order fit where PdI=2c/b².
(see slide 23 in cme.nuk.edu.tw/files/personal_subject/420_0f8d97a2.ppt)
Eventually, in the theoretical case of size distribution made of a single gaussian peak, the PdI may also be computed by sigma²/mean², which Saed Abbasi was rather close to.
(see p.18 in http://ncl.cancer.gov/NCL_Method_NIST-NCL_PCC-1.pdf)
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