1. Conventional particle size analysis methods cannot determine the particle size of specific components in final drug products. 2. It is important to measure the particle size distribution of active pharmaceutical ingredients in final dosage forms as it is a critical quality attribute. 3. Modern techniques like Morphologi G3-ID, solid state NMR, 2D-XRD, CLSM, and SEM-EDX allow determining the particle sizes of individual components in pharmaceutical formulations.

1. Measurement of component specific particle size in
pharmaceuticals: Challenges and solutions
National Institute of Pharmaceutical Education and Research
S.A.S. Nagar
Thum Akhila
M.S.(Pharm)
Department of Pharmaceutics

2. Introduction
Rationale of
particle size
measurement
Techniques for
Particle size
determination
Challenges and
solutions
Current
statusSummary
End of
Presentation
Flow of Presentation

3. API and
Excipients
Modifies Particle
size
Manufacturing
process
Decrease or increase in
size,
Polymorphic conversions,
Recrystallisation,
Agglomerates formation
Should be well
characterized
Introduction
Final Dosage forms
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
Wardrop J. et.al., 2006. J Pharm Sci 95(11):2380-2392. 1

4. Solubility and Dissolution Rate
Flow Property and Compression behavior
Content uniformity
Bioavailability
Rationale of Particle Size Measurement
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
Sun J. et.al., 2012. Int J Nanomed 7:5733. 2

5. Particle size determination techniques
Overall particle size distribution
Measurement of
particles in micron
range
- Laser Diffraction
- Digital Image
Processing
- Microscopy
- SEM
- TEM
- Scanning Probe
Microscope
- Atomic Force
Microscopy
Component Specific particle size
analysis
- Morphologi G3-ID
- solid state NMR
- 2D-XRD
- CLSM
- SEM-EDX
Measurement of
particles in nano
range
Techniques
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
Shekunov BY. et.al., 2007. Pharm Res 24(2):203-227. 3

6. Not suitable to measure the particle
size of the API in the final tablet
dosage form
Restricted to assume that the
particles being measured are
spherical in shape
Most of techniques based on using
powder samples
To measure nanoparticles with
these methods the particles should
be dispersed in a liquid
limitations with conventional methods of particle size measurement
0.5µm to
1000µm
30µm to
30mm
Down
to 1 nm
0.01nm
to 0.1nm
1nm to
8µm
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
4

7. 01
02
03
04
05
Detecting contaminants at low concentration in drug
product
To detect any physical conversions of the API that
occurs during processing
To identify the contaminants and differentiate
chemically between the actives and contaminant
Identification and quantification of one or more
individual components in counterfeit pharmaceutical
product
To determine the particle size of the drug in the matrix
in solid state
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
5
Challenges

8. SSNMR
SEM-EDX
CLSM
2D-XRD
Morphologi G3-ID 2D-XRD can only be used for grain size
estimation of crystalline samples with
known crystal structure
CLSM determines the drug crystal size in
solid state
It can be used to determine the drug
crystal size of only auto fluorescent drug
in a powder mixture
In SEM-EDX different molecules in the
mixture should contain different types of
atoms
Solutions
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
6

9.  Particle size range: 1µm to 1000µm
 Particle properties measured: size, shape, count, location and chemical identification
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
http://www.malvern.com/( Accessed on 15 October 2017)
Component specific particle size Morphologi G3-ID
Contd…
7

10. MorphologiG3-IDLaser from spectrometer through
Morphologi G3-ID objective down to
particles
2. Raman spectral acquisition
Active correlation
0.955
Operating Principle
Raman scattered light goes back
through Morphologi G3-ID objective
to Raman Spectrometer
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
http://www.malvern.com/ (Accessed on 15 October 2017)
1. Morphological
imaging
3. Chemical identification analysis
8

11. Shows the overlay of the particle size distributions (PSDs) for the individual active and excipient
components as well as for the overall nasal spray formulation in terms of number (where every particle
has equal weighing).
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
http://www.malvern.com/ (Accessed on 10 october 2017)
Case Study
9
Component specific particle sizing in orally inhaled and nasal drug products (OINDPs)

12. NMR parameters used in particle size analysis
Chemical shift Proton spin lattice relaxation Line width and peak area
Presence of certain Excipients
increases the line widths of
peaks of API
Schematic of 13C ssNMR
Spectrum of Ibuprofen and
mannitol
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
http://kuscholarworks.ku.edu.com (Accessed on 10 October 2017)
Component specific particle size solid sate NMR (ssNMR)
Highly defective crystalline
particles of API generated by
milling shows broader line widths
than as received API
10

13. Transfer of energy that occurs from the excited nuclei to the surroundings
Spin diffusion – Process through which nuclear magnetization is transferred through the sample to reach
relaxation sink
Proton spin lattice relaxation
Rate of spin diffusion
< d2 > = 6Dt
D – spin diffusion coefficient
t- time during which diffusion process occurs
d- distance from source of magnetization to the
relaxation sink
Rigid systems with long 1HT1 times (>10sec),time
t in equation corresponds to spin lattice
relaxation time and d corresponds to particle
size
Particle size
Increases
Decreases
1HT1 time increases
“d” will be longer
1HT1 time decreases
‘d ‘will be smaller
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
http://kuscholarworks.ku.edu.com (Accessed on 10 October 2017) 11

14. Determination of particle size of Dicoumarol by solid state NMR
• Same number of peaks at same chemical shift
indicating no polymorphic conversions occurred
upon milling. The line widths of the peaks in the
three spectra are also very similar
• 1HT1 time of Dicoumarol cryoground for 4 min
was 13 s
• 10 min cryoground material was 8 s
• 1H T1 of the received material 1500 s
• As The grinding decreased the size of the
particles, the 1HT1 time of crystalline Dicoumarol
decreased
13C NMR spectra of
a) Dicoumarol ( before cryogrond)
b) Dicoumarol ( cryoground for 4min)
c) Dicoumarol ( cryoground for 10min)
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
http://kuscholarworks.ku.edu.com (Accessed on 10 October 2017)
Case Study
12

15. Grain size of API in marketed formulation can be
determined by gamma profile of Debye rings in
2D-XRD diffraction frames
Suitable for crystallite sizes from as large as tens of
μm down to 100 nm with a small X-ray beam size
2D- XRD pattern from the sample with fine crystal
size shows a smooth diffraction ring and larger
crystals shows spotty diffraction rings
Based on spot intensities in a photographic film, the
grain size is calculated
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
Thakral S. et.al., 2017..J Pharm Sci.
Component specific particle size 2D-XRD
13
Contd…

16. 14
AFM images and XRD2 patterns of samples crystallized from
organic glass with large and small particle sizes
He. et.al., 2014. Powder Diffraction 29.2 : 113-117.
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
• d is the average diameter of the crystallite
particles (µm)
• Mhkl is multiplicity of diffracting plane
• A0 is the cross-section of the incident X-ray
beam
• β is the divergence of the incident X-ray
beam (rad)
• θ is angle between source and sample
surface (rad)
• ∆γ is the measured range of diffraction ring
• µ is the linear attenuation coefficient (µm-1)
• Ns number of crystallites contributing to the
diffraction pattern

17. Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
15
Comparison of the particle size of sucrose determined by the Laser
Diffraction and γ-integration methods
a-particle size outside the measurement range. See text for
details.
b-sample was a mixture of fines and grains
• Compacts prepared with sucrose
particles of size < 150 µm are not
effected by compression
• Compacts prepared with > 150µm
sucrose particles shows
continuous diffraction frames
• Shows that the compression leads
to formation of fine grains in it
Estimation of component specific particle size in intact tablets by 2D-XRD
Case Study
Thakral S,. et.al., 2017.J Pharm Sci.

18. • Single beam scanning microscopy
• Used with flourescence optics
Fluorescent light passes through pinhole at the focal
point
It is picked up by the detector
Fluorescence emitting sample fluoresces in all
directions under excitation from the laser
Part of fluorescence becomes focused at the focal
point of objective
Laser from light source passes through pinhole
aperture
Encounters dichromatic mirror and reflected at 90
degrees onto the objective lens
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
Pygall SR. et.al., 2007. Adv Drug Deliv Rev 59(14):1434-1452.
Component specific particle size CLSM
16

19. de Waard Hans. et al., 2011. Pharm Res 28.10 (2011): 2567-2574.
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
17
• Crystalline solid dispersion of dipyridamole was prepared
using mannitol and TBA
• Fluorescent dipyridamole signal separated from the
mannitol signal
• Deconvolution is carried out to get the clear image
• Images were converted into binary images. using ImageJ
1.41n (National Institutes of Health, USA)
• Volume-based particle size distribution was calculated
from the binary images
Case Study
Determining the size of drug crystals in solid dispersions

20. • EDX analysis performed in a SEM can be used for API molecules that contain elements responsive to EDX
Used for
imaging
Gives characteristic
chemical information
of the emitting
atoms
Generated with specific
energies for each element
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
Katewongsa P. et.al., 2017. J Pharma Invest 47(3):249-262.
Component specific particle size SEM-EDX
18

21. Current status
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
• Apotex developed a generic product Mometasone Furoate Nasal Spray
• The team at Malvern supported Apotex in their in vitro demonstration of bioequivalence for their generic
mometasone furoate nasal spray, accepted by the FDA in lieu of a clinical endpoint study
• Apotex used the Malvern Morphologi G3-ID, which applies the technique of MDRS to simultaneously
analyze the size, shape and chemical ID of individual particles within their nasal spray suspensions
• This unique capability enabled Apotex to confirm the form of the drug and its particle size and enabled the
FDA to bypass their requirement for a clinical-endpoint bioequivalence study
FDA highlights Malvern’s innovative Morphologi directed Raman
spectroscopy (MDRS) technology for Complex Generic drug product
development
http://www.materials-talks.com/ (Accessed on 10 November2017) 19

22. 1
Conventional methods available are limited to determine the overall particle size
distribution and not suitable for determining specific component particle size in final
dosage form
2
3
Summary
Measurement of component specific particles size in pharmaceuticals: Challenges and solutions
20
PSD of API is a Critical Quality Attribute (CQA) of the formulation, it is important to measure
this property in the final dosage form
Techniques like Morphologi G3-ID, ssNMR, 2D-XRD, CLSM and SEM-EDX are used to
determined the component specific particle size analysis in pharmaceuticals