Substandard and falsified medicine screening technologies

AAPS Open

Table 1 Summary of vibrational screening technologies

Characteristic	Infrared	Near Infrared	Raman
Principle	Fundamental absorptions	Overtone and combination absorptions	Emissions
Chemical sensitivity	Polar bonds	Polar bonds	Nonpolar bonds
Inherent selectivity	High	Low (modeling often required)	High
Sampling mode	Diamond ATR	Diffuse reflectance	180^o backscattering
Sampling configuration	Intimate contact with sample required	Stand-off detection possible but can be challenging	Stand-off
Excitation source	Broadband IR	Broadband IR	Monochromatic NIR i.e., 785 and 1064 nm
Interferences	Water and any packaging	Water, particle size/packing variability and opaque packaging	Fluorescence and opaque packaging
Minimum sample size required	At least 1 mg	~ 20–50 mg	~ 1 mg
Approximate penetration depths for solid dosage forms	~ 1–5 μm	~ 1–5 mm	~ 10–15 μm

Content from table 1 is pulled from the following references – Kauffman et al. (2010), Neospectra (2019), Rodriguez et al. (2014), Shimadzu (2019) and Zou et al. (2018)