Abstract

Dispersive Raman spectroscopy with excitation by a red diode laser is suitable for quantitative crystallinity measurements in powders for pulmonary drug delivery. In spray-dried mixtures of salmon calcitonin and mannitol, all three crystalline polymorphs of mannitol and amorphous mannitol were unambiguously identified and their mass fractions were measured with a limit of quantification of about 5%. The instrument design offered high sensitivity and adequate background suppression, resulting in a low limit of detection in the range of 0.01% to 1%. This spectroscopy method has significant advantages over established techniques regarding specificity, sensitivity, and sample requirements.

The Spectroscopy of Shock-Excited Powdered Solids

R. W. Nicholls, W. H. Parkinson, and E. M. Reeves
Appl. Opt. 2(9) 919-930 (1963)

Simple Crystal Powder Source for Raman Spectroscopy

Marvin C. Tobin
J. Opt. Soc. Am. 49(9) 850-853 (1959)

Improved detection sensitivity of D-mannitol crystalline phase content using differential spectral phase shift terahertz spectroscopy measurements

Jean-François Allard, Alain Cornet, Christophe Debacq, Marc Meurens, Daniel Houde, and Denis Morris
Opt. Express 19(5) 4644-4652 (2011)

Multi-excitation Raman spectroscopy technique for fluorescence rejection

Scott T. McCain, Rebecca M. Willett, and David J. Brady
Opt. Express 16(15) 10975-10991 (2008)

Raman spectroscopy: techniques and applications in the life sciences

Dustin W. Shipp, Faris Sinjab, and Ioan Notingher
Adv. Opt. Photon. 9(2) 315-428 (2017)