title: Red-excitation dispersive Raman spectroscopy is a suitable technique for solid-state analysis of respirable pharmaceutical powders.
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.
authors.affiliation: Nektar Therapeutics, San Carlos, California 94070, USA.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Vehring
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols / Q000032:analysis* / Q000737:chemistry; D002116:Calcitonin / Q000008:administration & dosage / Q000032:analysis* / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008353:Mannitol / Q000032:analysis / Q000737:chemistry; D010316:Particle Size; D004364:Pharmaceutical Preparations / Q000008:administration & dosage / Q000032:analysis* / Q000737:chemistry; D011208:Powders / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013059:Spectrum Analysis, Raman / Q000295:instrumentation* / Q000379:methods; D013678:Technology, Pharmaceutical / Q000295:instrumentation* / Q000379:methods
chemical_list: D000336:Aerosols; D004364:Pharmaceutical Preparations; D011208:Powders; D008353:Mannitol; C028815:salmon calcitonin; D002116:Calcitonin